LT3498 LINER
Document overview
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Technical content
LED CURRENT (mA) 0.1 100 250 300 400 200 100 150 350 EFFICIENCY (%) POWER LOSS (mW)
3498 TA01b
VIN = 3.6V VOUT2 = 16V POWER LOSS FROM VOUT2 TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
OLED Driver with Integrated Schottky in 3mm x 2mm DFN The LT®3498 is a dual output boost converter featuring a 2.3MHz PWM LED Driver and PFM OLED Driver. It includes an internal power switch and Schottky diode for each driver. Both converters can be independently shut down and modulated. This highly integrated power solution is ideal for dual display electronic devices. The 2.3MHz step-up converter is designed to drive up to six white LEDs in series from a Li-Ion cell. The device features a unique high side LED current sense that enables the part to function as a “one-wire” current source—one side of the LED string can be returned to ground anywhere. Traditional LED drivers use a grounded resistor to sense LED current, requiring a 2-wire connection to the LED string. The PFM OLED driver is a low noise boost converter that features a novel control technique. * The converter controls power delivery by varying both the peak inductor current and switch off time. This technique results in low output voltage ripple, as well as, high effi ciency over a wide load range. The off time of the switch is not allowed to exceed a fi xed level, guaranteeing a switching frequency that stays above the audio band. Li-Ion to Six White LEDs and OLED/LCD Bias ■ Dual Output Boost for Dual Display Devices ■ Drives Up to Six White LEDs and OLED/LCD Bias ■ Internal Power Switches and Schottky Diodes ■ Independent Dimming and Shutdown ■ 200mV High Side Sense on LED Driver Allows “One-Wire Current Source” ■ Wide Input Voltage Range: 2.5V to 12V ■ Wide Output Voltage Range: Up to 32V ■ 2.3MHz PWM Frequency for LED Driver ■ PFM for OLED Driver is Non-Audible Over Entire Load Range ■ Open LED Protection (27V Maximum on CAP1 Pin) ■ OLED Output Disconnect ■ Available in 12-Pin DFN Package ■ 1mm Tall Solution Height , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Patent Pending OLED Effi ciency SHUTDOWN AND DIMMING CONTROL SHUTDOWN AND CONTROL VIN 4.7µF 0.47 µF 16V 24mA 20mA 15µH15µH 1µF VIN = 3V TO 5V VOUT210Ω 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF ■ Cellular Phones ■ PDAs, Handheld Computers ■ Digital Cameras ■ MP3 Players ■ GPS Receivers
ELECTRICAL CHARACTERISTICS
V Operating Junction Temperature Range ...–40°C to 85°C (Notes 1, 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 2.5 V Maximum Operating Voltage 12 V Supply Current (LED Off, OLED Off) V IN = 3V, VCTRL1 = 0V, VCTRL2 = 0V 81 0 µ A Supply Current (LED On, OLED Off) V IN = 3V, VCTRL1 = 3V, VCTRL2 = 0V, VCAP1 = 24V, VLED1 = 23V 1.6 2 mA Supply Current (LED Off, OLED On) V IN = 3V, VCTRL1 = 0V, VCTRL2 = 3V, VFB2 = 3V 230 280 µA Supply Current (LED On, OLED On) V IN = 3V, VCTRL1 = 3V, VCTRL2 = 3V, VCAP1 = 24V, VLED1 = 23V 1.65 2.05 mA VCTRL1 for Full LED Current VCTRL2 for Full OLED Brightness
- 1.5 V VCTRL1 or VCTRL2 to Turn On IC ● 125 mV VCTRL1 and VCTRL2 to Shut Down IC ● 75 mV CTRL1, CTRL2 Pin Bias Current 100 nA LED Driver LED Current Sense Voltage (VCAP – VLED)V CAP1 = 24V, ISW = 200mA ● 190 200 210 mV CAP1, LED1 Pin Bias Current V CAP1 = 16V, VLED1 = 16V 20 30 µA VCAP1, VLED1 Common Mode Minimum Voltage 2.5 V Switching Frequency ● 1.8 2.3 2.8 MHz Maximum Duty Cycle 88 90 % Switch Current Limit ● 300 425 mA Switch VCESAT ISW = 200mA 250 mV TOP VIEW DDB PACKAGE 12-LEAD (3mm × 2mm) PLASTIC DFN LED1 CTRL1 GND1 GND2 CTRL2 FB2 CAP1 SW1 V IN SW2 CAP2 V OUT2 TJMAX = 125°C, θJA = 160°C/W EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER DDB PART MARKING LT3498EDDB LCQF Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C, VIN = 3V, VCTRL1 = VCTRL2 = 3V.
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: The LT3498 is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C junction operating temperature range are assured by design, characterization and correlation with statistical process controls. PARAMETER CONDITIONS MIN TYP MAX UNITS Switch Leakage Current V SW1 = 16V 0.1 5 µA CAP1 Pin Overvoltage Protection 26 27 28 V Schottky Forward Voltage I SCHOTTKY1 = 100mA 0.8 V Schottky Reverse Leakage V REVERSE1 = 20V 6 µA OLED Driver Feedback Voltage V CTRL2 = 3V (Note 3) ● 1.18 1.215 1.25 V Feedback Resistor ● 177 182 186 k Ω Minimum Switch Off Time After Start-Up 150 ns Minimum Switch Off Time During Start-Up (Note 4) 1 µs Maximum Switch Off Time V FB2 = 1.5V ● 15 20 30 µs Switch Current Limit 180 300 400 mA Switch VCESAT ISW2 = 200mA 260 mV Switch Leakage Current V SW2 = 16V 0.1 5 µA Schottky Forward Voltage I SCHOTTKY2 = 100mA 800 mV Schottky Reverse Leakage V REVERSE2 = 20V 2 µA PMOS Disconnect VCAP2 – VOUT2 IOUT2 = 10mA, VCAP2 = 5V 250 mV CTRL2 to FB2 Offset V CTRL2 = 0.5V 8 15 mV Maximum Shunt Current V FB2 = 1.3V 220 µA ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C, VIN = 3V, VCTRL1 = VCTRL2 = 3V. Note 3: Internal reference voltage is determined by fi nding VFB2 voltage level which causes quiescent current to increase 20µA above “Not Switching” level. Note 4: If CTRL2 is overriding the internal reference, start-up mode occurs when VFB2 is less then half the voltage on CTRL2. If CTRL2 is not overriding the internal reference, start-up mode occurs when VFB2 is less then half the voltage of the internal reference.
TEMPERATURE (°C) –50 –25
300 CURRENT LIMIT (mA)350
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VIN (V) OUTPUT CLAMP VOLTAGE (V) 2 468
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T = –50°C T = 150°C T = 25°C VIN (V) SHUTDOWN CURRENT (µA) 2 468
1635 G07
T = –50°C T = 125°C T = 25°C SWITCH CURRENT (mA) SWITCH SATURATION VOLTAGE (mV)50 150 200 250 500 350 100 200 250 100 400 450 300 50 150 300 350 400
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T = –50°C T = 125°C T = 25°C SCHOTTKY FORWARD DROP (mV) SCHOTTKY FORWARD CURRENT (mA) 150 200 250 600 1000 100 200 400 800 300 350 400
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T = –50°C T = 125°C T = 25°C VCTRL1 (mV) SENSE VOLTAGE (mV) 120 160 200 240 500 1000 1500 2000
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T = 25°C T = –50°C T = 125°C TEMPERATURE (°C) –50 –25
186 SENSE VOLTAGE (mV)
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T = –50°C CAP1 VOLTAGE (V) SENSE VOLTAGE (mV) 198 202 206 194 190 186 5 10 15 25
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T = 125°C T = 25°C TYPICAL PERFORMANCE CHARACTERISTICS Shutdown Current (VCTRL1 = VCTRL2 = 0V) LED Switch Saturation Voltage (V CESAT1) LED Schottky Forward Voltage Drop Sense Voltage (V CAP1 – VLED1) vs VCTRL1 Sense Voltage (VCAP1 – VLED1) vs Temperature Sense Voltage (VCAP1 – VLED1) vs VCAP1 LED Current Limit vs Temperature Open Circuit Output Clamp Voltage Input Current in Output Open Circuit T A = 25°C, unless otherwise specifi ed. VIN (V) INPUT CURRENT (mA) 468 1 0 12
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T = –50°C T = 150°C T = 25°C
TEMPERATURE (°C) –5 0 LED SWITCHING FREQUENCY (MHz) 2.5
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2.2 2.0 –2 5 0 5 0 1.9 1.8 2.6 2.4 2.3 2.1 75 100 125 SWITCH CURRENT (mA) SWITCH SATURATION VOLTAGE (mV) 100 150 200 300 50 100 150 200
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T = –50°C T = 125°C T = 25°C SCHOTTKY FORWARD DROP (mV) SCHOTTKY FORWARD CURRENT (mA) 150 200 250 600 12001000 100 200 400 800 300 350 400
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T = –50°C T = 125°C T = 25°C CTRL2 VOLTAGE (V) VOUT2 VOLTAGE (V) 1000 2000 500 1500
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TEMPERATURE (°C) –50 –25 OUTPUT VOLTAGE CHANGE (%) 0 50 75
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LOAD CURRENT (mA) VOUT2 VOLTAGE CHANGE (%) –0.5 0.5 30 50 –1.0 –1.5 –2.0 10 20 40 1.0 1.5 2.0
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TEMPERATURE (°C) –5 0 SWITCHING FREQUENCY (kHz)
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–2 5 0 5 0 75 100 125 LOAD CURRENT (mA) 0.1 SWITCHING FREQUENCY (kHz) 800 1000 1200 1 10 100
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TEMPERATURE (°C) –5 0 PEAK INDUCTOR CURRENT (mA) 550
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–2 5 0 5 0 250 200 600 500 450 350 75 100 125 TYPICAL PERFORMANCE CHARACTERISTICS LED Switching Frequency vs Temperature OLED Switch Saturation Voltage (V CESAT2) OLED Schottky Forward Voltage Drop V OUT2 vs VCTRL2 (VOUT2 = 16V) VOUT2 vs Temperature (VOUT2 = 16V) V OUT2 Load Regulation OLED Minimum Switching Frequency OLED Switching Frequency vs Load Current Peak Inductor Current T A = 25°C, unless otherwise specifi ed.
TYPICAL PERFORMANCE CHARACTERISTICS LED Switching Waveforms LED Transient Response OLED Switching Waveforms with No Load OLED Switching Waveforms with 4mA Load OLED Switching Waveforms with 35mA Load OLED Switching Waveforms During Start-Up PIN FUNCTIONS LED1 (Pin 1): Connection Point Between the Anode of the Highest LED and the Sense Resistor. The LED current can be programmed by: I mV RLED SENSE 200= CTRL1 (Pin 2): Dimming and Shutdown Pin. Connect this pin below 75mV to disable the white LED driver. As the pin voltage is ramped from 0V to 1.5V, the LED current ramps from 0 to (I LED1 = 200mV / RSENSE1). GND1, 2 (Pins 3, 4): Ground. Tie directly to local ground plane. GND1 and GND2 are connected internally. CTRL2 (Pin 5): Dimming and Shutdown Pin. Connect it below 75mV to disable the low noise boost converter. As the pin voltage is ramped from 0V to 1.5V, the output ramps up to the programmed output voltage. FB2 (Pin 6): Feedback Pin. Reference voltage is 1.215V. There is an internal 182kΩ resistor from FB2 to GND. To achieve desired output voltage, choose R FB2 according to the following formula: R V kFB OUT 2182 1 215 1=− ⎛ ⎠⎟• . Ω TA = 25°C, unless otherwise specifi ed. 500ns/DIV VSW 10V/DIV VCAP1 50mV/DIV IL 100mA/ DIV
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VIN = 3.6V FRONT PAGE APPLICATION 1ms/DIV VCAP1 5V/DIV VCTRL1 5V/DIV IL 200mA/ DIV
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VIN = 3.6V FRONT PAGE APPLICATION 5µs/DIV VOUT2 10mV/DIV AC COUPLED SW2 VOLTAGE 10V/DIV INDUCTOR CURRENT 50mA/DIV
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VIN = 3.6V VOUT2 = 16V
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2µs/DIV VOUT2 10mV/DIV AC COUPLED SW2 VOLTAGE 10V/DIV INDUCTOR CURRENT 200mA/DIV VIN = 3.6V VOUT2 = 16V
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VIN = 3.6V VOUT2 = 16V
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500µs/DIV VOUT2 VOLTAGE 5V/DIV CAP2 VOLTAGE 5V/DIV INDUCTOR CURRENT 100mA/DIV VIN = 3.6V VOUT2 = 16V
VOUT2 (Pin 7): Drain of Output Disconnect PMOS. Place a bypass capacitor from this pin to GND. See the Applications Information section. CAP2 (Pin 8): Output of the OLED Driver. This pin is connected to the cathode of the internal Schottky diode. Place a bypass capacitor from this pin to GND. SW2 (Pin 9): Switch Pin. This is the collector of the in- ternal NPN power switch. Minimize the metal trace area connected to this pin to minimize EMI. VIN (Pin 10): Input Supply Pin. Must be locally by- passed. SW1 (Pin 11): Switch Pin. Connect the inductor of the white LED driver at this pin. Minimize metal trace area at this pin to minimize EMI. CAP1 (Pin 12): Output of the White LED Driver. This pin is connected to the cathode of the internal Schottky. Connect the output capacitor to this pin and the sense resistor from this pin to the LED1 pin. Exposed Pad (Pin 13): Ground. The Exposed Pad must be soldered to the PCB. + – 6 5 Σ 11109 4 2 3 RAMP GENERATOR 2.3MHz OSCILLATORSWITCH CONTROL START-UP CONTROL VREF R S Q OVERVOLTAGE PROTECTION DISCONNECT CONTROL SHUNT CONTROL 3498 BD DRIVER DRIVER COMPARATORSW2 CAP1 LED1 VIN RSENSE1 10Ω VOUT2 CAP2 RC CC 1µF 0.47µF RFB2 2.21MΩ 10µF 10µF SW1 GND2 FB2 CTRL2 CTRL1 GND1 R 182kΩ CIN 4.7µF 15µF
by referring to the Block Diagram. CTRL1 is pulled lower than 75mV.
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4 LEDs
Figure 1. Switching Waveforms with
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output voltage by monitoring the voltage on the FB2 pin. will servo during regulation. the inductor current remains under control. effi ciency at higher load levels. function is often required in power supplies. inductors is shown in Figure 2. Figure 2. Effi ciency Comparison of Different Inductors are suffi cient for most applications.
Figure 3. Transient Response with The LT3498 LED Driver has a built-in Schottky diode.
- –
- • exp – • 2 2 where L is the inductance, r is the DCR of the inductor and C is the output capacitance. Table 3 gives inrush peak currents for some component selections. Table 3: Inrush Peak Currents VIN (V) r ( Ω) L (µH) C OUT (µF) I P (A) 4.2 0.58 15 1 0.828 4.2 1.6 15 1 0.682 4.2 0.8 15 1 0.794 4.2 0.739 15 1 0.803 500µs/DIV IL 200mA/DIV VCAP1 10V/DIV
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given in the Typical Performance Characteristics. by a RC network and fed to the CTRL1 pin. SENSE selection are shown below. There are three different types of dimming control circuits. control is a variable DC voltage to adjust the LED current. it has no effect on the LED current. Figure 4. Dimming Control Using a Filtered PWM Signal
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changes the intensity of the LEDs, it also changes the color. dimming offers a wider dimming range to the user. typical human eye has a limit of ~60 frames per second. CTRL1 pin of the LT3498 and the gate of the MOSFET. waveforms for the circuit in Figure 5. Figure 7. PWM Dimming Effi ciency Figure 5. Li-Ion to Four White LEDs Figure 6. Direct PWM Dimming Waveforms
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Figure 8. Dimming Ratio vs Freqeuncy
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Figure 9. Li-Ion to Four White LEDs with
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information and for their entire selection of related parts. to fi nd the correct inductance value for your design. the LT3498 (or at least provides a good starting point). node will give excellent transient response and stability. Table 6 shows a list of several capacitor manufacturers. and for their entire selection of related parts. Table 6. Recommended Ceramic Capacitor Manufacturers internal 1.215V reference and an auxiliary reference input. reference, and supplying an external reference voltage.
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internal reference. Figure 10 shows this behavior. necting the load to the CAP2 pin instead of the VOUT2 pin. Figure 10. CTRL2 to FB2 Transfer Curve Figure 11. Feedback Connection Using Figure 12. Improved Effi ciency
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Maximum Output Load Current The maximum output current of a particular LT3498 circuit is a function of several circuit variables. The fol- lowing method can be helpful in predicting the maximum load current for a given circuit: Step 1: Calculate the peak inductor current: II V L ampsPK LIMIT IN=+ •• –400 10 9 where ILIMIT is 0.3A for the OLED driver. L is the induc- tance value in Henrys and V IN is the input voltage to the boost circuit. Step 2: Calculate the inductor ripple current: I VV L ampsRIPPLE OUT IN= +() 2 91 150 10–•• – where VOUT2 is the desired output voltage. If the inductor ripple current is less then the peak current, then the circuit will only operate in discontinuous conduc- tion mode. The inductor value should be increased so that I RIPPLE < IPK. An application circuit can be designed to operate only in discontinuous mode, but the output current capability will be reduced. Step 3: Calculate the average input current: II I ampsIN AVG PK RIPPLE () –= 2 Step 4: Calculate the nominal output current: I IV V ampsOUT NOM IN AVG IN OUT () •• . 07 5 Step 5: Derate output current: I OUT = IOUT(NOM) • 0.7 amps For low output voltages the output current capability will be increased. When using output disconnect (load current taken from V OUT2), these higher currents will cause the drop in the PMOS switch to be higher resulting in reduced output current capability than those predicted by the preceding equations. Inrush Current When V IN is stepped from ground to the operating voltage while the output capacitor is discharged, a higher level of inrush current will fl ow through the inductor and integrated Schottky diode into the output capacitor. Conditions that increase inrush current include a larger more abrupt voltage step at V IN, a larger output capacitor tied to the CAP2 pin, and an inductor with a low saturation current. While the internal diode is designed to handle such events, the inrush current should not be allowed to exceed 1A. For circuits that use output capacitor values within the recommended range and have input voltages of less than 5V, inrush cur- rent remains low, posing no hazard to the device. In cases where there are large steps at V IN (more than 5V) and/or a large capacitor is used at the CAP2 pin, inrush current should be measured to ensure safe operation. APPLICATIONS INFORMATION—OLED DRIVER
paid to the PCB board layout and component placement. proper layout of high frequency switching paths is essential. Figure 13. Recommended Board Layout
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Li-Ion to Two White LEDs and OLED/LCD Bias TYPICAL APPLICATIONS SHUTDOWN AND DIMMING CONTROL SHUTDOWN AND CONTROL VIN 0.47µF 16V 24mA 20mA 10µH 10µH V IN = 3V TO 5V VOUT2 RFB2 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF RSENSE1 10Ω CIN 4.7µF CIN, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING C1: TAIYO YUDEN GMK212BJ105KG C3: TAIYO YUDEN TMK316BJ106ML L1, L2: MURATA LQH32CN100K53 1µF LED Effi ciency VIN = 3.6V, 2 LEDs LED CURRENT (mA) 51 0 2 0 EFFICIENCY (%)
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0.47µF 16V 24mA 20mA 10µH 10µH V IN = 3V TO 5V VOUT2 RFB2 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF RSENSE1 10Ω CIN 4.7µF CIN, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING C1: TAIYO YUDEN GMK212BJ105KG C3: TAIYO YUDEN TMK316BJ106ML L1, L2: MURATA LQH32CN100K53 1µF LED Effi ciency VIN = 3.6V, 2 LEDs LED CURRENT (mA) 51 0 2 0 EFFICIENCY (%)
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Li-Ion to Two White LEDs and OLED/LCD Bias
LED CURRENT (mA) 51 0 2 0 EFFICIENCY (%)
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0.47µF 16V 24mA 20mA 10µH 15µH V IN = 3V TO 5V VOUT2 RFB2 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF RSENSE1 10Ω CIN 4.7µF CIN, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING C1: TAIYO YUDEN GMK212BJ105KG C3: TAIYO YUDEN TMK316BJ106ML L1: MURATA LQH32CN150K53 L2: MURATA LQH32CN100K53 1µF LED Effi ciency VIN = 3.6V, 3 LEDs Li-Ion to Three White LEDs and OLED/LCD Bias
Li-Ion to Four White LEDs and OLED/LCD Bias TYPICAL APPLICATIONS SHUTDOWN AND DIMMING CONTROL SHUTDOWN AND CONTROL VIN 0.47µF 16V 24mA 20mA 10µH 15µH V IN = 3V TO 5V VOUT2 RFB2 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF RSENSE1 10Ω CIN 4.7µF CIN, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING C1: TAIYO YUDEN GMK212BJ105KG C3: TAIYO YUDEN TMK316BJ106ML L1: MURATA LQH32CN150K53 L2: MURATA LQH32CN100K53 1µF LED Effi ciency VIN = 3.6V, 4 LEDs LED CURRENT (mA) 51 0 2 0 EFFICIENCY (%)
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0.47µF 24V 24m A 10µH 15µH D1 VIN = 3V TO 5V VOUT2 RFB2 2.21MΩ
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FB2CTRL1LED1 CTRL2 GND2GND1 10µF ONOFF ONOFF CIN 4.7µF CIN, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING C1: TAIYO YUDEN GMK212BJ105KG C3: TAIYO YUDEN TMK316BJ106ML D1: CENTRAL SEMICONDUCTOR CMDSH-3 L1: MURATA LQH32CN150K53 L2: MURATA LQH32CN100K53 RSENSE1 10Ω 1µF 20mA LED Effi ciency, VIN = 3.6V, 6 LEDs OLED Effi ciency and Power Loss VIN = 3.6V, VOUT2 = 16V Li-Ion to Six White LEDs and OLED/LCD Bias LED CURRENT (mA) 51 0 2 0 EFFICIENCY (%)
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LOAD CURRENT (mA) 250 300 400 200 100 150 350 EFFICIENCY (%) POWER LOSS (mW)
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0.1 10 1 100
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 12-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1723 Rev Ø) 2.00 ±0.10 (2 SIDES) NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 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 ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 0.40 ± 0.10 BOTTOM VIEW—EXPOSED PAD 0.64 ± 0.10 (2 SIDES) 0.75 ±0.05 R = 0.115 TYPR = 0.05 TYP 2.39 ±0.10 (2 SIDES) 3.00 ±0.10 (2 SIDES) 127 PIN 1 BAR TOP MARK (SEE NOTE 6)
0.200 REF
0 – 0.05 (DDB12) DFN 0106 REV Ø 0.23 ± 0.05
0.45 BSC
R = 0.20 OR 0.25 × 45° CHAMFER 0.25 ± 0.05 2.39 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0.64 ±0.05 (2 SIDES) 1.15 ±0.05 0.70 ±0.05 2.55 ±0.05 PACKAGE OUTLINE
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007 LT 0507 • PRINTED IN USA RELATED PARTS TYPICAL APPLICATION PART NUMBER DESCRIPTION COMMENTS LT1932 Constant-Current, 1.2MHz, High Effi ciency White LED Boost Regulator VIN: 1V to 10V; VOUT(MAX) = 34V; IQ = 1.2mA; ISD = <1µA; ThinSOTTM Package LT1937 Constant-Current, 1.2MHz, High Effi ciency White LED Boost Regulator VIN: 2.5V to 10V; VOUT(MAX) = 34V; IQ = 1.9µA; ISD = <1µA; ThinSOT and SC70 Packages LT3463/ LT3463A Dual Output, Boost/Inverter, 250mA ISW, Constant Off-Time, High Effi ciency Step-Up DC/DC Converter with Integrated Schottky Diodes V IN: 2.3V to 15V; VOUT(MAX) = ±40V; IQ = 40µA; ISD = <1µA; 3mm × 3mm LT3465/ LT3465A Constant-Current, 1.2/2.7MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode V IN: 2.3V to 16V; VOUT(MAX) = 40V; IQ = 40µA; ISD = <1µA; 3mm × 3mm LT3466/ LT3466-1 Dual Constant-Current, 2MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode V IN: 2.3V to 16V; VOUT(MAX) = 40V; IQ = 65µA; ISD = <1µA; 3mm × 2mm LT3471 Dual Output, Boost/Inverter, 1.3A ISW, 1.2MHZ, High Effi ciency Boost-Inverting DC/DC Converter VIN: 2.4V to 16V; VOUT(MAX) = ±40V; IQ = 2.5µA; ISD = <1µA; 3mm × 3mm LT3473/ LT3473A 40V, 1A , 1.2MHz Micropower Low Noise Boost Converter with Output Disconnect V IN: 2.2V to 16V; VOUT(MAX) = 36V; IQ = 150µA; ISD = <1µA; 3mm × 3mm LT3491 Constant-Current, 2.3MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode VIN: 2.5V to 12V; VOUT(MAX) = 27V; IQ = 12.6µA; ISD = <8µA; 2mm × 2mm DFN-6 and SC70 Packages LT3494/ LT3494A 40V, 180mA/350mA Micropower Low Noise Boost Converter with Output Disconnect V IN: 2.3V to 16V; VOUT(MAX) = 40V; IQ = 65µA; ISD = <1µA; 3mm × 2mm LT3497 Dual 2.3MHz, Full Function LED Driver with Integrated Schottky Diode and 250:1 True Color PWMTM Dimming VIN: 2.5V to 10V; VOUT(MAX) = 32V; IQ = 6mA; ISD = <12µA; 3mm × 2mm LT3591 Constant-Current, 1MHz, High Effi ciency White LED Boost Regulator with Integrated Schottky Diode and 80:1 True Color PWM Dimming V IN: 2.5V to 12V; VOUT(MAX) = 40V; IQ = 4mA; ISD = <9µA; 3mm × 2mm ThinSot and True Color PWM are trademarks of Linear Technology Corporation Output Voltage Ripple vs Load Current VOUT RFB2 VALUE REQUIRED (MΩ) MAXIMUM OUTPUT CURRENT AT 3V INPUT (mA) 25 3.57 12.5 24 3.40 13.4 23 3.24 14.4 22 3.09 15.6 21 2.94 16.8 20 2.80 18.1 19 2.67 19.6 18 2.49 21.2 17 2.37 22.5 16 2.21 24.2 15 2.05 26 LOAD CURRENT (mA) 0.1 1 100 VOUT2 PEAK-TO-PEAK RIPPLE (mV)