LT3922EUFD LINEAR | Alldatasheet
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Technical content
3922fFor more information www.linear .com/L T3922 Typical applicaTion FeaTures DescripTion 36V, 2A Synchronous Step-Up LED Driver The LT®3922 is a monolithic, synchronous, step-up DC/ DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. The LT3922 will maintain ±2% current regulation through an external sense resistor over a wide range of output voltages. The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional Spread Spectrum Frequency Modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922 also includes a driver for an external high- side PFET for PWM dimming and an internal PWM signal generator for analog control of PWM dimming when an external signal is not available. Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions, and thermal shutdown. 2MHz, 93% Efficient 10W (30V, 333mA) Boost LED Driver Efficiency vs VIN
applicaTions
n ±2% LED Current Regulation n ±2% Output Voltage Regulation n 5000:1 PWM Dimming at 100Hz n 128:1 Internal PWM Dimming n Spread-Spectrum Frequency Modulation n Silent Switcher® Architecture for Low EMI n Operates in Boost, Buck Mode and Buck-Boost Mode n 2.8V to 36V Input Voltage Range n Up to 34V LED String Voltage n 2A, 40V Internal Switches n 200kHz to 2MHz with SYNC Function n Analog or Duty Cycle LED Current Control n Open/Short LED Protection and Fault Indication n Thermally Enhanced 28-Pin (4mm × 5mm) QFN n Automotive and Industrial Lighting n Machine Vision L, LT, LT C, LT M, Linear Technology, the Linear logo and Silent Switcher are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7199560, 7321203, and other patents pending. VINVIN 8V TO 27V 365k 59.0k 100k EN/UVLO OVLO VREF CTRLANALOG DIM PWM DIM PWM SYNC/SPRD INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA01a
33.2k 100k 10k 1nF 1µF 0.1µFL1 4.7µH 300m/uni03A9 4.7µF 0.47µF 0.47µF 30V 333mA LED SS 45.3k 2MHz 2.2µF 10nF 4.7µF V LED = 30V f SW = 2MHz 100% PWM Duty Cycle V IN (V) 100 EFFICIENCY (%)
3922 TA01b
3922f For more information www.linear .com/L T3922 pin conFiguraTionabsoluTe MaxiMuM raTings I IS V S BS INT Operating Junction Temperature Range (Notes 3, 4) 60 to 150°C (Note 1) 9 10 TOP VIEW UFD PACKAGE 28-LEAD (4mm × 5mm) PLASTIC QFN 11 12 13 28 27 26 25 GND 1SW BST INTVCC VIN EN/UVLO OVLO VREF CTRL GND VOUT PWMTG PWM RP SYNC/SPRD RT FAUL T SW SW NC NC V OUT GND ISP ISN VC FB SS ISMON 8 15 θJA = 34°C/W EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB elecTrical characTerisTics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted. LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3922EUFD#PBF LT3922EUFD#TRPBF 3922 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3922IUFD#PBF LT3922IUFD#TRPBF 3922 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3922HUFD#PBF LT3922HUFD#TRPBF 3922 28-Lead (4mm × 5mm) Plastic QFN –40°C to 150°C Consult L TC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. PARAMETER CONDITIONS MIN TYP MAX UNITS Input Voltage Range 2.8 36 V VIN Pin Quiescent Current VEN/UVLO = 1.5V, Not Switching VEN/UVLO = 0.1V, Shutdown 2.9 4 mA µA EN/UVLO Threshold (Falling) 1.260 1.330 1.400 V EN/UVLO Rising Hysteresis 25 mV EN/UVLO Pin Current VEN/UVLO = 1.2V 2 µA Input OVLO Threshold (Rising) 1.145 1.205 1.265 V Input OVLO Falling Hysteresis 50 mV OVLO Pin Current VOVLO = 1.0V –100 100 nA orDer inForMaTion http://www.linear.com/product/LT3922#orderinfo
3922fFor more information www.linear .com/L T3922
elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS Reference VREF Voltage IVREF = 0µA IVREF = 500µA l 1.97 1.985 2.03 2.015 V V V REF Pin Current Limit VREF = 0V, Current Out of Pin 3.2 mA LED Current Regulation CTRL-Off Threshold (Falling) l 200 210 220 mV CTRL-Off Rising Hysteresis 15 mV CTRL Pin Current VCTRL = 2V −100 100 nA Sense Voltage (VISP−VISN) (Analog Input) VCTRL = 2V (100%), VISP = 24V VCTRL = 0.75V (50%), VISP = 24V VCTRL = 0.3V (5%), VISP = 24V l l l 48.5 100 102 51.5 mV mV mV ISP Pin Current V ISP = 24.1V, VISN = 24V, VCTRL = 2V 75 µA ISN Pin Current VISP = 24.1V, VISN = 24V , VCTRL = 2V 75 µA Current Error Amplifier T ransconductance V ISP = 24V 140 µA/V Duty Cycle Control of LED Current Sense Voltage (VISP−VISN) (Duty Cycle Input) CTRL Duty = 75% (100%), VISP = 24V CTRL Duty = 37.5% (50%), VISP = 24V CTRL Duty = 15% (5%), VISP = 24V 100 101 mV mV mV CTRL Pulse Input High (V IH) 1.6 V CTRL Pulse Input Low (VIL) 0.4 V CTRL Pulse Input Frequency Range 10 200 kHz Voltage Regulation FB Regulation Voltage VCTRL = 2V l 1.175 1.200 1.225 V FB Pin Current FB in Regulation −100 100 nA Voltage Error Amplifier T ransconductance 1000 µA/V INTVCC Regulator INTVCC Voltage 2.7 3 3.3 V INTVCC Pin Current Limit VINTVCC = 0V, Current Out of Pin 20 mA Power Stage Peak Current Limit 2.0 2.3 2.6 A Bottom Switch Minimum Off-Time l 15 25 35 ns Bottom Switch On-Resistance 140 mΩ Top Switch On-Resistance 155 mΩ Oscillator Programmed Switching Frequency (f SW) R T = 45.3k, VSYNC/SPRD = 0V RT = 499k, VSYNC/SPRD = 0V l l 1880 175 2000 210 2120 245 kHz kHz Spread Spectrum Frequency Range R T = 45.3k, VSYNC/SPRD = 3V RT = 499k, VSYNC/SPRD = 3V 1880 175 2650 306 kHz kHz RT Pin Current Limit V RT = 0V, Current Out of Pin 75 µA SYNC/SPRD Threshold (Rising) 1.4 1.5 V SYNC/SPRD Falling Hysteresis 0.2 V SYNC/SPRD Pin Current VSYNC/SPRD = 5V −100 100 nA The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted.
3922f For more information www.linear .com/L T3922 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Do not apply a positive or negative voltage source to these pins, otherwise permanent damage may occur. Note 3: The LT3922E is guaranteed to meet performance specifications from 0°C to 125°C junction temperature. Specifications over the −40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT3922I is guaranteed to meet performance specifications over the −40°C to 125°C operating junction temperature range. The LT3922H is guaranteed over the −40°C to 150°C operating junction temperature range. Operating lifetime is derated at junction temperatures greater than 125°C. Note 4: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum rated junction temperature will be exceeded when this protection is active. Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage the device. PARAMETER CONDITIONS MIN TYP MAX UNITS Soft-Start SS Pin Charging Current VSS = 1V 20 µA SS Pin Discharging Current VSS = 2V 2 µA SS Lower Threshold 0.2 V SS Higher Threshold 1.7 V Fault Detection Open-Circuit Threshold (FB Rising) V ISP = VISN = 20V l 1.117 1.140 1.163 V Open-Circuit Falling Hysteresis 50 mV LED Short-Circuit Threshold (VISP − VISN) V ISP = 20V 150 mV FAUL T Pull-Down Current VFAUL T = 0.2V, VFB = 1.25V 0.8 mA FAUL T Leakage Current VFAUL T = 3V, VFB = 0.7V −100 100 nA Overvoltage Protection FB Overvoltage Threshold (Rising) l 1.240 1.266 1.292 V FB Overvoltage Falling Hysteresis 22 mV LED Current Monitor ISMON Voltage V ISP − VISN = 100mV (100%), VISP = 24V VISP − VISN = 10mV (10%), VISP = 24V l l 0.980 1.000 100 1.020 120 V mV PWM Driver P WMTG Gate Drive (VOUT – VPWMTG) V OUT = 20V, VPWM = 1.5V 9 10 11 V PWM Threshold (Rising) 1.4 V PWM Falling Hysteresis 0.2 V PWM Pin Current VPWM = 2V −100 100 nA PWM to PWMTG Propagation Delay Turn-On Turn-Off CPWMTG = 2.1nF (Connected from VOUT to PWMTG) VOUT = 20V 110 140 ns ns Internal PWM Dimming P WM Voltage for 100% PWM Dimming R P = 28.7k, VREF = 2V 2.00 V PWM Voltage for 0% PWM Dimming R P = 28.7k, VREF = 2V 0.99 V PWM Dimming Accuracy RP = 28.7k, VREF = 2V, VPWM = 1.1V RP = 28.7k, VREF = 2V, VPWM = 1.9V 7.5 10.5 13.5 PWM Dimming Frequency R P = 28.7k, RT = 45.3k, VSYNC/SPRD = 0V RP = 332k, RT = 45.3k, VSYNC/SPRD = 0V 7.34 115 7.81 122 8.28 129 kHz Hz RP Pin Current Limit VRP = 0V, Current Out of Pin 65 µA The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VEN/UVLO = 2V unless otherwise noted.
3922fFor more information www.linear .com/L T3922 Typical perForMance characTerisTics VIN Shutdown Current VIN Quiescent Current INTVCC Voltage INTVCC Load Regulation VREF Voltage VREF Load Regulation EN/UVLO Thresholds EN/UVLO Pin Current OVLO Threshold V IN = 36V V IN = 12V V IN = 2.7V TEMPERATURE (°C) –45 –20 105 130 155 0.50 1.00 1.50 2.00 2.50 V IN SHUTDOWN CURRENT (µA)
3922 G04
–40°C 25°C 125°C 150°C INTV CC LOAD CURRENT (mA) 2.80 2.85 2.90 2.95 3.00 3.05 3.10 INTV CC VOL TAGE (V)
3922 G07
V EN/UVLO = 1.2V TEMPERATURE (°C) –45 –20 105 130 155 0.50 1.00 1.50 2.00 2.50 3.00 EN/UVLO PIN CURRENT (µA)
3922 G02
TEMPERATURE (°C) –45 –20 105 130 155 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 V IN QUIESCENT CURRENT (mA)
3922 G05
V IN = 36V V IN = 12V V IN = 2.7V TEMPERATURE (°C) –50 –25 100 125 150 1.97 1.98 1.99 2.00 2.01 2.02 V REF VOL TAGE (V)
3922 G08
TEMPERATURE (°C) –50 –25 100 125 150 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 INTV CC VOL TAGE (V)
3922 G06
V IN = 36V V IN = 12V V IN = 2.7V V REF LOAD CURRENT (µA) 200 400 600 800 1000 1.97 1.98 1.99 2.00 2.01 2.02 V REF VOL TAGE (V)
3922 G09
–40°C 25°C 125°C 150°C VIN = 12V, TA = 25°C, unless otherwise noted. RISING FALLING TEMPERATURE (°C) –45 –20 105 130 155 1.20 1.25 1.30 1.35 1.40 1.45 1.50 EN/UVLO THRESHOLD (V)
3922 G01
TEMPERATURE (°C) –45 –20 105 130 155 1.05 1.10 1.15 1.20 1.25 1.30 1.35 OVLO THRESHOLD (V)
3922 G03
3922f For more information www.linear .com/L T3922 Typical perForMance characTerisTics RT and RP Pin Current Limits SS Currents SS Threshold Voltages Switching Frequency Internal PWM Frequency Internal PWM Duty Cycle VREF Line Regulation INTVCC and VREF UVLO Falling Thresholds Minimum Off Time V IN VOL TAGE (V) 1.990 1.992 1.994 1.996 1.998 2.000 2.002 2.004 2.006 2.008 2.010 VOL TAGE (V)
3922 G10
TEMPERATURE (°C) –45 –20 105 130 155 MAXIMUM PIN CURRENT (µA)
3922 G13
R T = 45.3k R T = 499k TEMPERATURE (°C) –45 –20 105 130 155 1400 1500 1600 1700 1800 1900 2000 2100 2200 180 190 200 210 220 230 240 250 260 SWITCHING FREQUENCY (kHz)
3922 G16
V REF UVLO TEMPERATURE (°C) –45 –20 105 130 155 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 THRESHOLD VOL TAGE (V)
3922 G11
TEMPERATURE (°C) –45 –20 105 130 155 CURRENT (µA)
3922 G14
R T = 45.3k R P = 28.7k R P = 332k TEMPERATURE (°C) –45 –20 105 130 155 6400 6784 7168 7552 7936 8320 110 116 122 128 134 140 INTERNAL PWM FREQUENCY (Hz)
3922 G17
TEMPERATURE (°C) –45 –20 105 130 155 MINIMUM OFF TIME (ns)
3922 G12
TEMPERATURE (°C) –45 –20 105 130 155 0.4 0.8 1.2 1.6 2.0 THRESHOLD VOL TAGE (V)
3922 G15
R T = 45.3k R P = 332k TEMPERATURE (°C) –45 –20 105 130 155 10.0 10.1 10.2 10.3 10.4 10.5 INTERNAL PWM DUTY CYCLE (%)
3922 G18
18.2k 22.1k VIN = 12V, TA = 25°C, unless otherwise noted.
3922fFor more information www.linear .com/L T3922 Typical perForMance characTerisTics 100% Current Regulation 5% Current Regulation ISMON Voltage Peak SW Current Limit ILED vs VIN ILED vs VOUT VISP – VISN vs VCTRL VISP – VISN vs DCTRL VISP – VISN vs VFB V CTRL (V) 0.25 0.50 0.75 1.25 1.50 1.75 100 125 V ISP – V ISN (mV)
3922 G19
f SW = 2MHz L = 4.7µH
12 LEDs (V
~ 36V)
6 LEDs (V
~ 18V) DUTY CYCLE (%) 100 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 PEAK SW CURRENT (A)
3922 G25
PULSE FREQUENCY AT CTRL PIN = 20kHz D CTRL (%) 12.5 37.5 62.5 87.5 100 100 125 V ISP – V ISN (mV)
3922 G20
f SW = 2MHz R SNS = 0.3/uni03A9
11 LEDs (VOUT ~33V)
V IN (V) 100 150 200 250 300 350 400 I LED (mA)
3922 G26
V FB (V) 1.17 1.18 1.19 1.20 1.21 1.22 100 125 V ISP – V ISN (mV)
3922 G21
–40°C 25°C 125°C V ISP – V ISN (mV) 100 200 400 600 800 1000 ISMON (mV)
3922 G24
f SW = 2MHz VIN = 8V R SNS = 0.3/uni03A9 R FB_TOP = 1M R FB_BOT = 34.8k V FB OVERVOL TAGE PROTECTION LIMITED V OUT (V) 100 150 200 250 300 350 400 I LED (mA)
3922 G27
N = 355 V CTRL = 2V V ISP = 24V 150°C 25°C –40°C ISP–ISN VOL TAGE (mV) 98.6 99.3 100 100.7 101.4 100 150 200 250 300 350 NUMBER OF UNITS
3922 G22
N = 355 V CTRL = 0.3V V ISP = 24V 150°C 25°C –40°C ISP–ISN VOL TAGE (mV) 4.2 4.6 5.4 5.8 120 160 200 NUMBER OF UNITS
3922 G23
VIN = 12V, TA = 25°C, unless otherwise noted.
3922f For more information www.linear .com/L T3922 Typical perForMance characTerisTics Efficiency vs VIN Efficiency vs ILED Regulated FB Voltage PWMTG ON Voltage PWM Driver Propagation Delay FB OVLO Threshold FB OPENLED Threshold VISP – VISN SHORTLED Threshold Power Switch On-Resistance RISING FALLING TEMPERATURE (°C) –45 –20 105 130 155 0.90 0.95 1.00 1.05 1.10 1.15 1.20 FB OPENLED THRESHOLD (V)
3922 G28
I LED = 400mA
11 LEDs (V
~ 33V) f SW = 400kHz f SW = 2MHz V IN (V) 100 EFFICIENCY (%)
3922 G31
TEMPERATURE (°C) –45 –20 105 130 155 V OUT – V PWMTG (V)
3922 G34
TEMPERATURE (°C) –45 –20 105 130 155 120 130 140 150 160 170 180 V ISP – V ISN SHORTLED THRESHOLD (mV)
3922 G29
V IN = 12V f SW = 2MHz
6 LED (V
~ 18V)
9 LED (V
~ 27V)
12 LED (V
~ 36V) I LED (mA) 200 400 600 800 1000 100 EFFICIENCY (%)
3922 G32
C PWMTG = 2.2nF (C0G type) TURN OFF TURN ON TEMPERATURE (°C) –45 –20 105 130 155 120 160 200 PROPAGATION DELAY (ns)
3922 G35
TEMPERATURE (°C) –45 –20 105 130 155 100 150 200 250 300 350 POWER SWITCH ON–RESISTANCE (m/uni03A9)
3922 G30
TEMPERATURE (°C) –45 –20 105 130 155 1.18 1.19 1.20 1.21 1.22 1.23 FB VOL TAGE (V)
3922 G33
TEMPERATURE (°C) –45 –20 105 130 155 1.18 1.21 1.24 1.27 1.30 1.33 FB OVLO THRESHOLD VOL TAGE (V)
3922 G36
VIN = 12V, TA = 25°C, unless otherwise noted.
3922fFor more information www.linear .com/L T3922 Typical perForMance characTerisTics Internal PWM Duty Cycle (90%) Input Voltage T ransient Response Input Voltage T ransient Response Turn ON and OFF Performance Start-Up with 10% Internal PWM Start-Up with 50% Internal PWM C/10 Threshold Case Temperature Rise Internal PWM Duty Cycle (10%) TEMPERATURE (°C) –45 –20 105 130 155 V ISP – V ISN C/10 THRESHOLD (mV)
3922 G37
V LED = 30V I LED = 333mA T ROOM = 25°C f SW = 2MHz f SW = 400kHz V IN (V) CASE TEMPERATURE RISE (°C)
3922 G38
N = 359 150°C 25°C –40°C PWM DUTY CYCLE (%) 8.6 9.4 10.2 11.0 11.8 100 150 200 250 300 350 NUMBER OF UNITS
3922 G39
N = 359 150°C 25°C –40°C PWM DUTY CYCLE (%) 90.2 90.6 91.4 92.2 93.0 93.4 100 150 200 250 300
3922 G40
6.5V to 18V INPUT VOL TAGE TRANSIENT VLED = 30V I LED = 333mA 5ms/DIV I LED 100mA/DIV V IN 5V/DIV
3922 G41
18V to 6.5V INPUT VOL TAGE TRANSIENT I LED = 333mA 5ms/DIV I LED 100mA/DIV V IN 5V/DIV
3922 G42
VLED = 30V FRONT PAGE APPLICATION I LED = 333mA 500µs/DIV I LED 100mA/DIV V IN 10V/DIV
3922 G43
VLED = 30V FRONT PAGE APPLICATION WITH PWM = 1.1V I LED = 333mA 5ms/DIV I LED 100mA/DIV V IN 10V/DIV V OUT 10V/DIV
3922 G44
VLED = 30V FRONT PAGE APPLICATION WITH PWM = 1.5V I LED = 333mA 5ms/DIV I LED 100mA/DIV V IN 10V/DIV V OUT 10V/DIV
3922 G45
VLED = 30V VIN = 12V, TA = 25°C, unless otherwise noted.
3922f For more information www.linear .com/L T3922 pin FuncTions SW: Switch Pins. These pins are internally connected to the power devices and drivers. They should always be tied together. In normal operation, the voltage of these pins will switch between the output voltage and zero at the programmed frequency. Do not force any voltage on these pins. BST: Boost Pin. This pin supplies the top power switch GATE driver. Connect a 100nF capacitor between this pin and SW close to the package. An internal diode from INTV CC to BST will charge the capacitor when the SW pin switches low. INTVCC: Internally Regulated, Low-Voltage Supply Pin. This pin provides the power for the converter switch GATE drivers. Do not force any voltage on this pin. Place a 2.2µF bypass capacitor to GND close to the package. V IN: Input Voltage Pin. This pin supplies power to the internal, high-performance analog circuitry. Connect a bypass capacitor between this pin and GND. EN/UVLO: Enable and Undervoltage Lockout Pin. A volt- age at this pin greater than 1.33V will enable switching, and a voltage less than 0.1 V is guaranteed to shut down the internal current bias and sub-regulators. A resistor network between this pin and ground can be used to set the pin voltage and automatically lockout the part when V IN is below a certain level. No internal components pull up or down on this pin, so it requires an external voltage bias for normal operation. This pin may be tied directly to V IN. OVLO: Input Overvoltage Lockout Pin. When the voltage at this pin rises above 1.205V, the system disables switch- ing and resets the soft-start capacitor. Do not leave this pin open. Tie this pin to GND when the OVLO function is not used. VREF: Reference Voltage Pin. This pin provides a buffered 2V reference capable of 3mA drive. It can be used to supply resistor networks for setting the voltages at the CTRL and PWM pins. Bypass with a 1μF capacitor to GND. CTRL: Control Pin. An analog voltage from 250mV to 1.25V at this pin programs the regulated voltage between ISP and ISN (and therefore, the regulated current supplied to the load). Alternatively, a digital pulse at this pin with duty cycle from 12.5% to 62.5% can be used to program the regulated voltage. Below 200mV or 10% duty cycle, the CTRL pin voltage disables switching. For more detail, see Typical Performance Characteristics and Applications Information sections. ISP: Positive Current Sense Pin. This pin is one of the inputs to the internal current sense error amplifier. It should be connected to the positive side of the external sense resis- tor. Use Kelvin connection for accurate current sensing. ISN: Negative Current Sense Pin. This pin is one of the inputs to the internal current sense error amplifier. It should be connected to the negative side of the external sense resistor. Use Kelvin connection for accurate cur - rent sensing. V C: Compensation Pin. A resistor and capacitor connected in series from this pin to GND stabilize the current and voltage regulation. Typical resistor and capacitor values are from 0k to 100k and from 0.1nF to 10nF, respectively. FB: Feedback Pin. When the voltage at this pin is near 1.2V the regulated current is automatically reduced from the programmed value. A resistor network between this pin and V OUT can be used to set a limit for the output voltage. If the voltage at the FB pin reaches 1.266V, a FB overvolt- age lockout comparator disables switching. SS: Soft-Start Pin. At startup and recovery from fault conditions, a 20μA current charges the capacitor and the FB voltage tracks the rising voltage at this pin until the load current reaches its programmed level. Typical values for the capacitor are 10nF to 100nF. Using a single resistor from SS to INTV CC, the LT3922 can be set in two differ - ent fault modes for the shorted LED conditions: hiccup (no resistor ) and latchoff (100k). Refer to the Application Information section for a detailed explanation. ISMON: Output Current Monitoring Pin. This pin provides a buffered voltage output equal to 10mV for every 1mV between ISP and ISN.
3922fFor more information www.linear .com/L T3922 pin FuncTions FAUL T: Fault Pin. Connect to INTVCC through a resistance of 100k. An internal switch pulls this pin low when any of following conditions happen: 1. Open LED: VFB > 1.14V and (VISP – VISN) < 10mV 2. Shorted LED: (VISP – VISN) > 150mV for more than 300us, or (VISP – VISN) > 0.7V, or VOUT < (VIN – 2V) RT: Timing Resistor Pin. A resistor from this pin to GND programs the switching frequency between 200kHz and 2MHz. Do not leave this pin open. SYNC/SPRD: Synchronization Pin. To override the pro - grammed switching frequency, drive this pin with an external clock having a frequency between 200 kHz and 2MHz. Even when using the external clock, select an R T resistor that corresponds to the desired switching fre - quency. Tie the pin to INTVCC to enable Spread Spectrum Frequency Modulation. This pin should be tied to GND when not in use. RP: PWM Resistor Pin. Connect a resistor from this pin to GND to set the frequency of the internal PWM signal. Do not use a resistor larger than 1MΩ. If using an external PWM pulse for LED dimming, tie this pin to GND. Refer to the Application Information section for a detailed explanation. PWM: PWM Input Pin. With the RP pin tied to GND, drive this pin with a digital pulse to control PWM dimming of the LEDs. Alternatively, when using a resistor on the RP pin to GND, set the voltage of this pin between 1V and 2V to generate an internal pulse with duty cycle between 0% and 100%. When using an analog signal, place a 1µF bypass capacitor between this pin and GND. Tie this pin high when PWM dimming is not required. PWMTG: PWM Driver Output Pin. This pin can drive the gate of an external high-side PMOS device for PWM dim- ming of LEDs. Do not force any voltage on this pin. V OUT: Output Pins. Connect to the output and place output capacitors between these pins and GND as close as pos- sible to the package. Refer to the Application Information section for the recommended capacitor placements. GND (Pin 22, 23, 25, Exposed Pad Pin 29): Ground Pins. All GND pins must be soldered to the board ground plane. NC: No Connect Pins. These pins can be left open or con- nected to the ground.
3922f For more information www.linear .com/L T3922 block DiagraM 3 282 27 1 INTERNAL VCC REGULATOR UVLO AND OVLO 2V REFERENCE 59.0k 10µF VIN 2.2µF 0.1µF 4.7µH SYNCHRONOUS CONTROLLER S R Q 1µF 356k EN/UVLO VIN INTVCC BST MTSW MBSW 200m/uni03A9 SW OVLO VOUT GNDVREF SYNC/SPRD CTRL 200kHz TO 2MHz OSCILLATOR GND (EXPOSED PAD) 0.47µF 4.7µF VOUT ISN 3922 BD ISP FB 0.47µF RT SS 25 26 N/C N/C VC RP 1.4V 1.205V 20µA 2µA 45.3k 33.2k 2.5k 100k 2.5k S/H S/H VOUT – 10V REGULATOR INTERNAL PWM SIGNAL SOFT-START AND LED FAUL T CONTROL gm = 140µA/V CURRENT REGULATION AMPLIFIER V/I CONVERTER gm = 1000µA/V VOL TAGE REGULATION AMPLIFIER PEAK CURRENT COMPARATOR 1.25V 0.25V PWMTG DRIVER PWM PWMTG ISMON FAUL T INTVCC 10× CONTROL BUFFER 25k A/D DETECTOR 1nF 10nF 10k
3922fFor more information www.linear .com/L T3922 operaTion The LT3922 is a step-up LED driver that utilizes a fixed- frequency peak current control to accurately regulate the current through a string of LEDs. It includes two power switches, their drivers, and a diode for providing power to the top switch driver. The switches connect an external inductor at the SW pin alternately to the ground and then to the output (V OUT). The inductor current rises and falls accordingly and the peak current can be regulated by adjusting the duty ratio of the power switches through the combined effect of the other circuit blocks. The synchronous controller ensures the power switches do not conduct at the same time, and a programmable oscillator turns on the bottom switch at the beginning of each switching cycle. The frequency of this oscillator is set by an external resistor at the RT pin and can be overrid - den by external pulses at the SYNC/SPRD pin. The SYNC/ SPRD pin can also be used to command spread spectrum frequency modulation (SSFM), which reduces radiated and conducted electromagnetic interference (EMI). The bottom switch is turned off by the peak current com- parator which waits during the on-time for the increasing inductor current to exceed the target set by the voltage at the V C pin. This target is modified by a signal from the oscillator which stabilizes the inductor current. A network of passive components at the VC pin is necessary to stabilize this regulation loop. The target for the inductor current is derived from the desired LED current programmed by the voltage at the CTRL pin. The analog-to-digital detector and the control buffer convert either a DC voltage or duty cycle of pulses at the CTRL pin into the input for the current regulation amplifier. The other input to this amplifier comes from the ISP and ISN pin voltages. An external current sense resistor between these pins should be placed in series with the string of LEDs such that the voltage across it provides the feedback to regulate the LED current. The current regulation amplifier then compares the actual LED current to the desired LED current and adjusts V C as necessary. The voltage regulation amplifier overrides the current regulation amplifier when the FB pin voltage is higher than an internal 1.2V reference. An external resistor network from the LED string to the FB pin provides an indication of the LED string voltage and allows the voltage amplifier to prevent overvoltage of the LED string. The ISP, ISN, and FB pin voltages are also monitored to detect fault conditions like open and short circuits, which are then reported by pulling FAUL T pin low. The response to a fault can be selected either to try hiccup restarts or to latchoff by the choice of an external resistor connected to the SS pin. Refer to the Applications Information section for a detailed explanation of fault responses. Finally, pulse-width modulation (PWM) of the LED current is achieved by turning on and off an external PMOS switch between the V OUT and the string of LEDs. An external pulse at the PWM pin controls the state of the PWM driver or a DC voltage at the PWM pin dictates the duty ratio of an internal PWM pulse, whose frequency is programmed with an external resistor at the RP pin. After each pulse, when the PMOS switch opens, the LT3922 preserves the voltages of the capacitors at V C and VOUT to ensure a rapid recovery for the next pulse. applicaTions inForMaTion The following is a guide to selecting the external com - ponents and configuring the LT3922 according to the requirements of an application. Programming LED Current with the CTRL Pin The primary function of the LT3922 is to regulate the cur- rent in a string of LEDs. This current should pass through a series current sense resistor . The voltage across this resistor is sensed by the current regulation amplifier through the ISP and ISN pins and regulated to a level pro- grammed by the CTRL pin. The maximum resistor voltage that can be programmed is 100 mV which corresponds to 1A through the LED string when a 100mΩ current sense resistor is used. To allow for this maximum current, the CTRL pin may be connected directly to the V REF pin which provides
greater than 1.6V. The low level must be less than 0.4V. will vary with the duty ratio of the pulse as shown in Figure 2. increase switching power losses and radiated EMI. Table 1. RT Resistance Range Figure 1. Analog CTRL Range Figure 2. Duty Cycle CTRL Range Figure 3. Setting CTRL with NTC Resistors
3922 F01
3922 F02
3922 F03
measurements are with select typical application circuits. Figure 4. Typical Conducted Peak EMI of the LT3922 with 2MHz should correspond to the frequency of the external clock. T resistor to set the frequency. SSFM is required, connect SYNC/SPRD to GND. various standard industrial tests related to interference. of 2A over the duty cycle without sub-harmonic oscillations.
3922 F04
suming 90% efficiency for the given conditions. are recommended sources of inductors. Table 2. Inductor Manufacturers capacitor types over wide voltage and temperature ranges. ditional bulk electrolytic capacitance may be necessary. capacitors are listed in Table 3. Table 3. Capacitor Manufacturers to VC pin create the dominant pole of the control loop. over wide voltage and temperature ranges. OUT should be bypassed with three capacitors.
Figure 5. Placement of Output Capacitors
3922 F05
age until the FB pin voltage approaches 1.2V. affected noticeably by gate charging loss or transition loss. Table 4. PMOS Manufacturers
Table 5. Internal PWM Dimming Frequencies capacitor near PWM pin to ground. has reached approximately 10% of the full-scale current. Figure 7. FB Resistor Configuration Figure 6. ISMON Filter Configuration to maintain the charge on the capacitors at those pins. if PWM was low for a very long time. 10k resistor would limit the ripple on ISMON to 1%. the output voltage and the FB pin as shown in Figure 7.
3922 F06
3922 F07
Figure 8. FAUL T Resistor Configuration the 1.266V FB overvoltage lockout threshold.
3922 F08
when the LEDs are conducting a large current. other parts to be connected and share a single resistor. until the part successfully restarts.
Figure 10. Fault Responses: (a) Latchoff and (b) Hiccup Figure 11. EN/UVLO Threshold and Hysteresis Voltages old can be accurately set by an external resistor divider. threshold and the rising hysteresis voltages in LT3922.
3922 F10
Figure 9. SS Capacitor and Resistor Configuration
3922 F09
drive the LED at the commanded current level.
3922 F11
Figure 12. OVLO Threshold and Hysteresis Voltages Figure 13. EN/UVLO–OVLO Threshold and Hysteresis Voltages voltage is below the threshold. package are necessary to dissipate heat. their connections should be made on that layer. the second layer dissipates heat, but also reduces noise. excessive inductance in the LED string. demo board layout of the LT3922 for more information. single resistor string consisting of three series resistors. hysteresis voltages for EN/UVLO and OVLO. used. Do not leave these pins open. to be higher than the operational temperature of the part.
3922 F12
3922 F13
3922f For more information www.linear .com/L T3922 Typical applicaTions 333mA Boost LED Driver Using External PWM and Strobe 5000:1 External PWM Dimming 100µs Strobe/1s Period 100:1 External PWM Dimming 100µs Strobe/100s Period 500ns/DIV ILED 100mA/DIV VPWM 2V/DIV
3922 TA02b
VIN = 18V fPWM = 100Hz 20µs/DIV ILED 100mA/DIV VPWM 2V/DIV
3922 TA02c
V IN = 18V fPWM = 100Hz 20µs/DIV ILED 100mA/DIV VPWM 2V/DIV
3922 TA02d
V IN = 18V fPWM = 1Hz 20µs/DIV ILED 100mA/DIV VPWM 2V/DIV
3922 TA02e
V IN = 18V fPWM = 0.01Hz VINVIN 8V TO 27V 365k 59.0k EN/UVLO OVLO VREF PWM CTRL SYNC/SPRD INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA02a
33.2k 100k 51k 1nF 1µF 0.1µFL1 2.2µH 300m/uni03A9 10µF 0.47µF 0.47µF 30V 333mA LED SS 45.3k 2MHz10nF 2.2µF L1: WURTH 74437324022 M1: VISHAY Si2319CDS 4.7µF
3922fFor more information www.linear .com/L T3922 Typical applicaTions 333mA Boost LED Driver Using Internal PWM and Analog CTRL Dimming 128:1 Internal PWM Dimming 128:1 Internal PWM with 20:1 Analog CTRL Dimming 10:1 Internal PWM Dimming 10:1 Internal PWM with 20:1 Analog CTRL Dimming 10µs/DIV ILED 100mA/DIV
3922 TA03b
VCTRL = 2V VIN = 12V fPWM = 122Hz 200µs/DIV ILED 100mA/DIV
3922 TA03c
VCTRL = 2V VIN = 12V fPWM = 122Hz 10µs/DIV ILED 10mA/DIV
3922 TA03d
VCTRL = 0.3V VIN = 12V fPWM = 122Hz 200µs/DIV ILED 10mA/DIV
3922 TA03e
VCTRL = 0.3V VIN = 12V fPWM = 122Hz VINVIN 8V TO 27V 365k 59.0k EN/UVLO OVLO VREF PWM CTRLVCTRL SYNC/SPRD INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA03a
33.2k 100k 97.6k 100k 10k 1nF 1µF 0.1µF (OPTION) 0.1µFL1 4.7µH 300m/uni03A9 4.7µF 0.47µF 0.47µF 30V 333mA LED SS 45.3k 2MHz 332k 122Hz 10nF 2.2µF L1: WURTH 74437324047 M1: VISHAY Si2319CDS 4.7µF
3922f For more information www.linear .com/L T3922 Typical applicaTions 333mA Boost LED Driver Using External PWM Dimming and SSFM 122Hz 10:1 External PWM Dimming with and without SSFM 2ms/DIV ILED (SSFM) 200mA/DIV ILED (NO SSFM) 200mA/DIV
3922 TA04b
4.7µF 365k 59.0k EN/UVLO OVLO VREF PWM CTRL SYNC/SPRD SSFM INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA04a
33.2k 100k 10k 1nF 1µF 0.1µFL1 4.7µH 300m/uni03A9 4.7µF 0.47µF 0.47µF 30V 333mA LED SS 45.3k 2MHz10nF 2.2µF L1: WURTH 74437324047 M1: VISHAY Si2319CDS
3922fFor more information www.linear .com/L T3922 Typical applicaTions Low EMI 400kHz, 96% Efficient 10W (30V, 333mA) Boost LED Driver with SSFM Efficiency vs VIN Peak Radiated EMI Performance (CISPR25) Average Radiated EMI Performance (CISPR25) V LED = 30V f SW = 400kHz WITHOUT EMI FIL TERS WITH EMI FIL TERS V IN (V) 100 EFFICIENCY (%)
3922 TA05b
FREQUENCY (MHz) 100 200 300 400 500 600 700 800 900 1000 –15 –10 AMPLITUDE (dBµV/m)
3922 TA05c
FREQUENCY (MHz) 100 200 300 400 500 600 700 800 900 1000 –15 –10 AMPLITUDE (dBµV/m)
3922 TA05d
27V 4.7µF 365k 59.0k EN/UVLO OVLO VREF PWMPWM DIM ANALOG DIM CTRL SYNC/SPRD INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA05a
33.2k 100k 10k 10µF 0.1µF 0402 33µF 1nF 1µF 0.1µFL1 22µH 300m/uni03A9 4.7µF 2.2µF 0.47µF 0.47µF FB2 OUTPUT EMI FIL TER INPUT EMI FIL TER FB1 30V 333mA LED SS 249k 400kHz 10nF 2.2µF L1: COILCRAFT XAL5050-223MEB M1: VISHAY Si2319CDS FB1: WURTH 742792040 FB2: WURTH 742792097 D1: NXP PMEG4010CEJ 0402 0.1µF
3922f For more information www.linear .com/L T3922 Typical applicaTions 500mA Boost LED Driver Using Pulse Duty Cycle CTRL Input VCTRL Duty Cycle Stepped from 15% to 75% VCTRL Duty Cycle Stepped from 75% to 15% 1ms/DIV ILED 200mA/DIV VCTRL 2V/DIV
3922 TA06b
3922 TA06c
4.7µF 348k 84.5k EN/UVLO OVLO VREF CTRL PWM SYNC/SPRD 3V , 10kHz PULSE INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA06a
33.2k 100k 10k 1nF 1µF 0.1µFL1 6.8µH 200m/uni03A9 4.7µF 0.47µF 0.47µF 24V 500mA LED SS 45.3k 2MHz 10nF 2.2µF L1: WURTH 74437324068 M1: VISHAY Si2319CDS
3922fFor more information www.linear .com/L T3922 Efficiency vs VIN Typical applicaTions 2MHz, 95% Efficient 15W (15V, 1A) Buck Mode LED Driver VINVIN 20V TO 36V VIN 20V TO 36V 33µF 51.1k 34.8k EN/UVLO OVLO SYNC/SPRD INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA07a
33.2k 100k 1µF 4.7nF 0.1µF 4.7µH 100m/uni03A9 22µF 0.47µF 0.47µF 15V LED SS 45.3k 2MHz100nF 2.2µF L1: WURTH 74437324047 M1: VISHAY Si2319CDS Q1: ZETEX FMMT591A 20k 20k VREF PWMPWM DIM ANALOG DIM CTRL 100k1µF V IN (V) 100 EFFICIENCY (%)
3922 TA07b
3922f For more information www.linear .com/L T3922 Typical applicaTions Efficiency I LOAD (mA) 100 200 300 400 500 100 EFFICIENCY (%)
3922 TA08b
Short-LED Robust Boost LED Driver 500mA, 5V to 12V Boost Converter with Accurate Input Current Limit Shorted LED Protection without RSS: Hiccup Mode Shorted LED Protection with RSS: Latchoff Mode 20ms/DIV ILED 1A/DIV VPWMTG 20V/DIV VSS 2V/DIV VFAUL TB 2V/DIV
3922 TA09b
3922 TA09c
2.2µF 84.5k 182k EN/UVLO OVLO INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISN GND GND ISP PWMTG ISMON
3922 TA08a
60.4k 100k 10k 1nF 0.1µFL1 4.7µH 10µF VOUT 12V 500mA0.47µF 0.47µF SS 45.3k 2MHz 10nF 2.2µF 56m/uni03A9 L1: WURTH 744316470 SYNC/SPRD VREF PWMPWM DIM ANALOG DIM CTRL 100k1µF VINVIN 8V TO 18V 4.7µF 226k 80.6k EN/UVLO OVLO INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA09a
33.2k 100k 10k 1nF 0.1µFL1 4.7µH M1 D1 200m/uni03A9 4.7µF 0.47µF 0.47µF 21V 500mA LED SS 45.3k 2MHz RSS 100k OPTIONAL 332k 122Hz 10nF2.2µF L1: WURTH 74437324047 M1: VISHAY Si2319CDS D1: NXP PMEG4010CEJ SYNC/SPRD VREF PWMPWM DIM ANALOG DIM CTRL 100k1µF
3922fFor more information www.linear .com/L T3922 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. package DescripTion Please refer to http://www.linear.com/product/LT3922#packaging for the most recent package drawings. 4.00 ±0.10 (2 SIDES)
2.50 REF
5.00 ±0.10 (2 SIDES) NOTE: 1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WXXX-X). 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT , SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONL Y A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE PIN 1 TOP MARK (NOTE 6) 0.40 ±0.10 27 28 BOTTOM VIEW—EXPOSED PAD
3.50 REF
0.75 ±0.05 R = 0.115 TYP R = 0.05 TYP PIN 1 NOTCH R = 0.20 OR 0.35 × 45° CHAMFER 0.25 ±0.05
0.50 BSC
0.200 REF
0.00 – 0.05 (UFD28) QFN 0506 REV B RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPL Y SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0.70 ±0.05 0.25 ±0.05 4.10 ±0.05 5.50 ±0.05 2.65 ±0.05 3.10 ±0.05 4.50 ±0.05 PACKAGE OUTLINE 2.65 ±0.10 3.65 ±0.10 3.65 ±0.05 28-Lead Plastic QFN (4mm × 5mm) (Reference LTC DWG # 05-08-1712 Rev B)
3922f For more information www.linear .com/L T3922 LINEAR TECHNOLOGY CORPORATION 2016 LT 0816 • PRINTED IN USA Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com/L T3922 relaTeD parTs Typical applicaTion PART NUMBER DESCRIPTION COMMENTS LT3952 60V, 4A LED Driver with 4000:1 PWM Dimming with Spread Spectrum VIN: 3V to 42V, V OUT(MAX) = 60V, 4000:1 PWM , 20:1 Analog, I SD < 1µA, LT3518 2.3A, 2.5MHz High Current LED Driver with 3000:1 Dimming with PMOS Disconnect FET Driver VIN: 3 V to 30V, V OUT(MAX) = 45V, 3000:1 PWM Dimming, I SD < 1μA, 4mm × 4mm QFN-16 and TSSOP-16E Packages LT3755 /LT3755-1/ LT3755-2 40VIN, 75V OUT, 1MHz Non-Synchronous Boost LED Controller VIN: 4.5V to 40V, V OUT: V IN to 75V, ±4% Current Accuracy, 3mm × 3mm QFN-16 and MSE-16 LT3761 60VIN, 80V OUT, 1MHz Non-Synchronous Boost LED Controller with Internal PWM Generator VIN: 4.5V to 60V, VOUT: VIN to 80V, ±3% Current Accuracy, External and Internal PWM Dimming, MSE-16 LT3763 60V, 1MHz Synchronous Buck LED Controller V IN: 6V to 60V, VOUT: 0V to VIN –2V, ±6% Current Accuracy, TSSOP-28 LT3744 36V, 1 MHz Synchronous Buck LED Controller with Four-State Control VIN: 3.3V to 36V, V OUT: 0V to 36V, ±2% Current Accuracy, Fast Four-State Current Control, 5mm × 6mm QFN-36 LT3795 110V, 1MHz Non-Synchronous Boost LED Controller with Spread Spectrum Frequency Modulation VIN: 4.5V to 110V, V OUT: V IN to 110V, ±3% Current Accuracy, Internal Spread Spectrum, TSSOP-28 LT8391 60V, 650kHz Synchronous 4-Switch Buck-Boost LED Controller with Spread Spectrum VIN: 4V to 60V, VOUT: 0V to 60V, ±3% Current Accuracy, External and Internal PWM Dimming, Spread Spectrum, TSSOP-28 and 4mm × 5mm QFN-28 Low EMI 2MHz, 333mA Boost LED Driver with SSFM Peak Radiated EMI Performance (CISPR25) Average Radiated EMI Performance (CISPR25) CLASS 5 PEAK LIMIT L T3922 2MHz f SW PEAK EMI FREQUENCY (MHz) 100 200 300 400 500 600 700 800 900 1000 –15 –10 AMPLITUDE (dBµV/m)
3922 TA10b
FREQUENCY (MHz) 100 200 300 400 500 600 700 800 900 1000 –15 –10 AMPLITUDE (dBµV/m)
3922 TA10c
4.7µF 365k 59.0k EN/UVLO OVLO INTVCC FAUL T BST SW VOUT VOUT FB RP V CRT ISP GND GND ISN PWMTG ISMON
3922 TA10a
33.2k 24k 0.1µF 0402 33µF 0.22nF 0402 0.1µF 0.1µF 4.7µH M1 D1 300m/uni03A9 2.2µF 0.47µF 0.47µF FB2 OUTPUT EMI FIL TER FB1 INPUT EMI FIL TER 30V 333mA LED SS 45.3k 2MHz 332k 122Hz 100nF 2.2µF L1: WURTH 74437324047 M1: VISHAY Si2319CDS FB1: WURTH 7427920415 FB2: WURTH 742792097 D1: NXP PMEG4010 CEJ SYNC/SPRD VREF PWMPWM DIM ANALOG DIM CTRL 100k1µF 100k 2.2µF