LT1933_1 LINER | Alldatasheet
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FEATURES
APPLICATIONS
DESCRIPTION
600mA, 500kHz Step-Down Switching Regulator in SOT- 23 and DFN Packages The L T®1933 is a current mode PWM step-down DC/DC converter with an internal 0.75A power switch, packaged in a tiny 6-lead SOT-23. The wide input range of 3.6V to 36V makes the L T1933 suitable for regulating power from a wide variety of sources, including unregulated wall transformers, 24V industrial supplies and automotive batteries. Its high operating frequency allows the use of tiny, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple. Cycle-by-cycle current limit provides protection against shorted outputs, and soft-start eliminates input current surge during start up. The low current (<2μA) shutdown provides output disconnect, enabling easy power manage- ment in battery-powered systems. 3.3V Step-Down Converter n Wide Input Range: 3.6V to 36V n 5V at 600mA from 16V to 36V Input n 3.3V at 600mA from 12V to 36V Input n 5V at 500mA from 6.3V to 36V Input n 3.3V at 500mA from 4.5V to 36V Input n Fixed Frequency 500kHz Operation n Uses Tiny Capacitors and Inductors n Soft-Start n Internally Compensated n Low Shutdown Current: <2μA n Output Adjustable Down to 1.25V n Low Profi le (1mm) SOT-23 (ThinSOT™) and (2mm x 3mm x 0.75mm) 6-Pin DFN Packages n Automotive Battery Regulation n Industrial Control Supplies n Wall T ransformer Regulation n Distributed Supply Regulation n Battery-Powered Equipment L, L T , L TC and L TM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Effi ciency VIN 4.5V TO 36V OFF ON 0.1μF 22μH 1N4148 MBRM140 10k 16.5k 22μF
1933 TA01a
2.2μF VOUT 3.3V/500mA VIN BOOST GND FB SHDN SW L T1933 LOAD CURRENT (mA) 300 400
1933 TA01b
EFFICIENCY (%) VIN = 12V VOUT = 5V VOUT = 3.3V
Operating Temperature Range (Note 2) (Note 1) TOP VIEW FB GND SHDN BOOST V IN SW DCB PACKAGE 6-LEAD (2mm × 3mm) PLASTIC DFN θJA = 73.5°C/W , θJC = 12°C/W EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB BOOST 1 GND 2 FB 3 6 SW
5 VIN
4 SHDN
θJA = 165°C/W , θJC = 102°C/W PIN CONFIGURATION ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1933IDCB#PBF L T1933IDCB#TRPBF LCGM 6-Lead (2mm × 3mm) Plastic DFN –40°C to 125°C L T1933HDCB#PBF L T1933HDCB#TRPBF LCGN 6-Lead (2mm × 3mm) Plastic DFN –40°C to 150°C L T1933ES6#PBF L T1933ES6#TRPBF L TAGN 6-Lead Plastic TSOT-23 –40°C to 85°C L T1933IS6#PBF L T1933IS6#TRPBF L TAGP 6-Lead Plastic TSOT-23 –40°C to 125°C L T1933HS6#PBF L T1933HS6#TRPBF L TDDQ 6-Lead Plastic TSOT-23 –40°C to 150°C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1933IDCB L T1933IDCB#TR LCGM 6-Lead (2mm × 3mm) Plastic DFN –40°C to 125°C L T1933HDCB L T1933HDCB#TR LCGN 6-Lead (2mm × 3mm) Plastic DFN –40°C to 150°C L T1933ES6 L T1933ES6#TR L TAGN 6-Lead Plastic TSOT-23 –40°C to 85°C L T1933IS6 L T1933IS6#TR L TAGP 6-Lead Plastic TSOT-23 –40°C to 125°C L T1933HS6 L T1933HS6#TR L TDDQ 6-Lead Plastic TSOT-23 –40°C to 150°C Consult L TC Marketing for parts specifi ed with wider operating temperature ranges. For more information on lead free part marking, go to: http://www.linear .com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear .com/tapeandreel/ Maximum Junction Temperature Lead Temperature, S6 Package
ELECTRICAL CHARACTERISTICS
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 L T1933E is guaranteed to meet performance specifi cations from 0°C to 70°C. Specifi cations over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The L T1933I specifi cations are PARAMETER CONDITIONS MIN TYP MAX UNITS Undervoltage Lockout 3.35 3.6 V Feedback Voltage l 1.225 1.245 1.265 V FB Pin Bias Current V FB = Measured VREF + 10mV (Note 4) l 40 120 nA Quiescent Current Not Switching 1.6 2.5 mA Quiescent Current in Shutdown V SHDN = 0V 0.01 2 μA Reference Line Regulation V IN = 5V to 36V 0.01 %/V Switching Frequency V FB = 1.1V 400 500 600 kHz VFB = 0V 55 kHz Maximum Duty Cycle l 88 94 % Switch Current Limit (Note 3) 0.75 1.05 A Switch V CESAT ISW = 400mA, S6 Package ISW = 400mA, DCB6 Package 370 370 500 mV mV Switch Leakage Current 2μ A Minimum Boost Voltage Above Switch I SW = 400mA 1.9 2.3 V BOOST Pin Current I SW = 400mA 18 25 mA SHDN Input Voltage High 2.3 V SHDN Input Voltage Low 0.3 V SHDN Bias Current V SHDN = 2.3V (Note 5) VSHDN = 0V 0.01 0.1 μA μA The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V , VBOOST = 17V , unless otherwise noted. (Note 2) guaranteed over the –40°C to 125°C temperature range. The L T1933H specifi cations are guaranteed over the –40°C to 150°C temperature range. Note 3: Current limit guaranteed by design and/or correlation to static test. Slope compensation reduces current limit at higher duty cycle. Note 4: Current fl ows out of pin. Note 5: Current fl ows into pin.
TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency, VOUT = 5V Effi ciency, V OUT = 3.3V Switch Current Limit Maximum Load Current Maximum Load Current Switch Voltage Drop Feedback Voltage Undervoltage Lockout Switching Frequency LOAD CURRENT (mA) 100 300 400
1933 G01
EFFICIENCY (%) VIN = 24V VIN = 12V TA = 25°C VOUT = 5V D1 = MBRM140 L1 = Toko D53LCB 33 μH LOAD CURRENT (mA) 100 300 400
1933 G02
EFFICIENCY (%) VIN = 24V VIN = 12V VIN = 5V TA = 25°C VOUT = 3.3V D1 = MBRM140 L1 = Toko D53LCB 22 μH DUTY CYCLE (%) SWITCH CURRENT LIMIT (mA) 600 800 1200 1000
1933 G03
TA = 25°C INPUT VOL TAGE (V) LOAD CURRENT (mA) 600 700
1933 G04
L = 22μH L = 33μH TA = 25°C VOUT = 5V INPUT VOL TAGE (V) LOAD CURRENT (mA) 600 700
1933 G05
L = 22μH L = 15μH TA = 25°C VOUT = 3.3V SWITCH CURRENT (A) SWITCH VOL TAGE (mV) 100 200 300 400 600 500 0.2 0.4
1933 G06
0.60.1 0.3 0.5 TA = 85°C TA = 25°C TA = –40°C TEMPERATURE (°C) FEEDBACK VOL TAGE (V) 1.260 1.255 1.250 1.240 1.230 1.245 1.235
1933 G07
–50 –25 0 25 50 75 100 150 125 TEMPERATURE (°C) UVLO (V) 3.8 3.6 3.4 3.2 3.0
1933 G08
–50 –25 0 25 50 75 100 150 125 TEMPERATURE (°C) SWITCHING FREQUENCY (kHz) 600 550 500 450 400
1933 G09
–50 –25 0 25 50 75 100 150 125
TYPICAL PERFORMANCE CHARACTERISTICS Frequency Foldback Soft-Start SHDN Pin Current Typical Minimum Input Voltage Typical Minimum Input Voltage Switch Current Limit Operating Waveforms Operating Waveforms, Discontinuous Mode FB PIN VOLTAGE (V) 0.0 SWITCHING FREQUENCY (kHz) 700 600 300 100 400 500 200 0.5
1933 G10
1.0 1.5 TA = 25°C SHDN PIN VOLTAGE (V) SWITCH CURRENT LIMIT (A) 1.4 1.2 0.6 0.2 0.8 1.0 0.4
1933 G11
TA = 25°C DC = 30% SHDN PIN CURRENT (μA) 200 150 100
1933 G12
SHDN PIN VOLTAGE (V) TA = 25°C LOAD CURRENT (mA) INPUT VOLTAGE (V)
1933 G13
VOUT = 5V TA = 25°C L = 33μH TO START TO RUN 1 10 100 LOAD CURRENT (mA) 4.5 INPUT VOLTAGE (V) 5.0 5.5 6.0
1933 G14
3.0 3.5 4.0 VOUT = 3.3V TA = 25°C L = 22μH TO START TO RUN 1 10 100 TEMPERATURE (°C) –50 SWITCH CURRENT LIMIT (A) 1.4 1.2 1.0 0.6 0.2 0.8 0.4 –25 0 25
1933 G15
VIN = 12V , VOUT = 3.3V , IOUT = 400mA, L = 22μH, COUT = 22μF
1933 G16
1.8V VOUT2 1.2V VSW 10V/DIV VIN = 12V , VOUT = 3.3V , IOUT = 20mA, L = 22μH, COUT = 22μF
1933 G17
1.8V VOUT2 1.2V VSW 10V/DIV
BOOST (Pin 1): The BOOST pin is used to provide a drive voltage, higher than the input voltage, to the internal bipolar NPN power switch. GND (Pin 2/Pin 5 and Exposed Pad, Pin 7): Tie the GND pin to a local ground plane below the L T1933 and the circuit components. Return the feedback divider to this pin. FB (Pin 3/Pin 6): The L T1933 regulates its feedback pin to 1.245V . Connect the feedback resistor divider tap to this pin. Set the output voltage according to V OUT = 1.245V (1 + R1/R2). A good value for R2 is 10k. SHDN (Pin 4): The SHDN pin is used to put the L T1933 in shutdown mode. Tie to ground to shut down the L T1933. Tie to 2.3V or more for normal operation. If the shutdown feature is not used, tie this pin to the V IN pin. SHDN also provides a soft-start function; see the Applications Infor- mation section. V IN (Pin 5/Pin 2): The V IN pin supplies current to the L T1933’s internal regulator and to the internal power switch. This pin must be locally bypassed. SW (Pin 6): The SW pin is the output of the internal power switch. Connect this pin to the inductor , catch diode and boost capacitor . (SOT-23/DFN) BLOCK DIAGRAM Σ R DRIVER Q1S OSC SLOPE COMP FREQUENCY FOLDBACK INT REG AND UVLO VC gm 1.245V 1933 BD Q Q BOOST SW FB R2 R1 VOUT C1D1 VIN VIN ON OFF GND SHDN
OPERATION (Refer to Block Diagram) The L T1933 is a constant frequency, current mode step down regulator . A 500kHz oscillator enables an RS fl ip- fl op, turning on the internal 750mA power switch Q1. An amplifi er and comparator monitor the current fl owing between the V IN and SW pins, turning the switch off when this current reaches a level determined by the voltage at V C. An error amplifi er measures the output voltage through an external resistor divider tied to the FB pin and servos the V C node. If the error amplifi er’s output increases, more current is delivered to the output; if it decreases, less cur- rent is delivered. An active clamp (not shown) on the V C node provides current limit. The VC node is also clamped to the voltage on the SHDN pin; soft-start is implemented by generating a voltage ramp at the SHDN pin using an external resistor and capacitor . An internal regulator provides power to the control cir- cuitry. This regulator includes an undervoltage lockout to prevent switching when V IN is less than ~3.35V . The SHDN pin is used to place the L T1933 in shutdown, dis- connecting the output and reducing the input current to less than 2μA. The switch driver operates from either the input or from the BOOST pin. An external capacitor and diode are used to generate a voltage at the BOOST pin that is higher than the input supply. This allows the driver to fully saturate the internal bipolar NPN power switch for effi cient opera- tion. The oscillator reduces the L T1933’s operating frequency when the voltage at the FB pin is low. This frequency foldback helps to control the output current during startup and overload. APPLICATIONS INFORMATION FB Resistor Network The output voltage is programmed with a resistor divider between the output and the FB pin. Choose the 1% resis- tors according to: R1 = R2(V OUT/1.245 – 1) R2 should be 20k or less to avoid bias current errors. Reference designators refer to the Block Diagram. Input Voltage Range The input voltage range for L T1933 applications depends on the output voltage and on the absolute maximum rat- ings of the V IN and BOOST pins. The minimum input voltage is determined by either the L T1933’s minimum operating voltage of ~3.35V , or by its maximum duty cycle. The duty cycle is the fraction of time that the internal switch is on and is determined by the input and output voltages: DC = (V OUT + VD)/(VIN – VSW + VD) where VD is the forward voltage drop of the catch diode (~0.4V) and VSW is the voltage drop of the internal switch (~0.4V at maximum load). This leads to a minimum input voltage of: V IN(MIN) = (VOUT + VD)/DCMAX – VD + VSW with DCMAX = 0.88 The maximum input voltage is determined by the absolute maximum ratings of the VIN and BOOST pins and by the minimum duty cycle DC MIN = 0.08 (corresponding to a minimum on time of 130ns): V IN(MAX) = (VOUT + VD)/DCMIN – VD + VSW Note that this is a restriction on the operating input voltage; the circuit will tolerate transient inputs up to the absolute maximum ratings of the V IN and BOOST pins. Inductor Selection and Maximum Output Current A good fi rst choice for the inductor value is: L = 5 (V OUT + VD) where VD is the voltage drop of the catch diode (~0.4V) and L is in μH. With this value the maximum load current will be above 500mA. The inductor’s RMS current rating must be greater than your maximum load current and its
Table 1.Inductor Vendors Vendor URL Part Series Inductance Range (μH) Size (mm) MSS5131 10 to 22 3.1 × 5.1 × 5.1 MSS6122 10 to 33 2.2 × 6.1 × 6.1 CDRH4D28 10 to 33 3.0 × 5.0 × 5.0 CDRH5D28 22 to 47 3.0 × 5.7 × 5.7 D53LC 22 to 47 3.0 × 5.0 × 5.0 WE-PD4 S 10 to 22 2.9 × 4.5 × 6.6 WE-PD2 S 10 to 47 3.2 × 4.0 × 4.5 saturation current should be about 30% higher . For robust operation in fault conditions the saturation current should be ~1A. To keep effi ciency high, the series resistance (DCR) should be less than 0.2Ω. Table 1 lists several vendors and types that are suitable. Of course, such a simple design guide will not always re- sult in the optimum inductor for your application. A larger value provides a slightly higher maximum load current, and will reduce the output voltage ripple. If your load is lower than 500mA, then you can decrease the value of the inductor and operate with higher ripple current. This allows you to use a physically smaller inductor , or one with a lower DCR resulting in higher effi ciency. There are several graphs in the Typical Performance Characteristics section of this data sheet that show the maximum load current as a function of input voltage and inductor value for several popular output voltages. Low inductance may result in discontinuous mode operation, which is OK, but further reduces maximum load current. For details of maximum output current and discontinuous mode opera- tion, see Linear Technology Application Note 44. Finally, for duty cycles greater than 50% (V OUT/VIN > 0.5), there is a minimum inductance required to avoid subharmonic oscillations. Choosing L greater than 3(V OUT + V D) μH prevents subharmonic oscillations at all duty cycles. Catch Diode A 0.5A or 1A Schottky diode is recommended for the catch diode, D1. The diode must have a reverse voltage rating equal to or greater than the maximum input voltage. The ON Semiconductor MBR0540 is a good choice; it is rated for 0.5A forward current and a maximum reverse voltage of 40V . The MBRM140 provides better effi ciency, and will handle extended overload conditions. Input Capacitor Bypass the input of the L T1933 circuit with a 2.2μF or higher value ceramic capacitor of X7R or X5R type. Y5V types have poor performance over temperature and ap- plied voltage, and should not be used. A 2.2μF ceramic is adequate to bypass the L T1933 and will easily handle the ripple current. However , if the input power source has high impedance, or there is signifi cant inductance due to long wires or cables, additional bulk capacitance may be necessary. This can be provided with a low performance electrolytic capacitor . Step-down regulators draw current from the input sup- ply in pulses with very fast rise and fall times. The input capacitor is required to reduce the resulting voltage ripple at the L T1933 and to force this very high frequency
switching current into a tight local loop, minimizing EMI. A 2.2μF capacitor is capable of this task, but only if it is placed close to the L T1933 and the catch diode; see the PCB Layout section. A second precaution regarding the ceramic input capacitor concerns the maximum input voltage rating of the L T1933. A ceramic input capacitor combined with trace or cable inductance forms a high quality (under damped) tank circuit. If the L T1933 circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the L T1933’s voltage rating. This situation is easily avoided; see the Hot Plugging Safely section. Output Capacitor The output capacitor has two essential functions. Along with the inductor , it fi lters the square wave generated by the L T1933 to produce the DC output. In this role it determines the output ripple, and low impedance at the switching frequency is important. The second function is to store energy in order to satisfy transient loads and stabilize the L T1933’s control loop. Ceramic capacitors have very low equivalent series re- sistance (ESR) and provide the best ripple performance. A good value is C OUT = 60/VOUT where COUT is in μF . Use X5R or X7R types, and keep in mind that a ceramic capacitor biased with V OUT will have less than its nominal capacitance. This choice will provide low output ripple and good transient response. T ransient performance can be improved with a high value capacitor , but a phase lead capacitor across the feedback resistor R1 may be required to get the full benefi t (see the Compensation section). High performance electrolytic capacitors can be used for the output capacitor . Low ESR is important, so choose one that is intended for use in switching regulators. The ESR should be specifi ed by the supplier , and should be 0.1Ω or less. Such a capacitor will be larger than a ceramic capacitor and will have a larger capacitance, because the capacitor must be large to achieve low ESR. Table 2 lists several capacitor vendors. Table 2.Inductor Vendors Vendor Phone URL Part Series Comments Panasonic (714) 373-7366 www.panasonic.com Ceramic, Polymer , Tantalum EEF Series Kemet (864) 963-6300 www.kemet.com Ceramic, Tantalum T494, T495 Sanyo (408) 749-9714 www.sanyovideo.com Ceramic, Polymer , Tantalum POSCAP Murata (404)436-1300 www.murata.com Ceramic AVX www.avxcorp.com Ceramic, Tantalum TPS Series Taiyo Yuden (864)963-6300 www.taiyo-yuden.com Ceramic
of the higher ESR of this capacitor . Figure 1. T ransient Load Response of the L T1933 with Different
1933 F01a
1933 F01b
1933 F01c
capacitor and a small Schottky diode (such as the BAT-54). voltage rating of the BOOST pin is not exceeded. Figure 2. T wo Circuits for Generating the Boost Voltage Figure 3. The Minimum Input Voltage Depends on Output Voltage, Load Current and Boost Circuit
1933 F02a
1933 F02b
1933 F03a
1933 F03b
the absolute maximum rating of the BOOST pin. input voltage to maintain regulation. can supply 60μA when the SHDN pin reaches 2.3V . Figure 4. To Soft-Start the L T1933, Add a Resistor and Capacitor to
1933 F04a
1933 F04b
a shorted or reversed input. Figure 5. Diode D4 Prevents a Shorted Input from Discharging a Backup
1933 F05
Figure 6. A Well Chosen Input Network Prevents Input Voltage Overshoot and
1933 F06
rings as high as 35V and the input current peaks at 20A. achieve low output ripple and small circuit size. test the stability using a transient load. Figure 7. Model for Loop Response
1933 F07
heat from the L T1933 to the ground plane. the thermal resistance of the L T1933. Figure 8. A Good PCB Layout Ensures Proper , Low EMI Operation
1933 F08a
1933 F08b
3.3V Step-Down Converter 12V Step-Down Converter VIN 4.5V TO 36V OFF ON 0.1μF 22μH 10k 16.5k 22μF 6.3V
1933 TA02b
2.2μF VOUT 3.3V/ 500mA VIN BOOST GND FB SHDN SW L T1933 VIN 14.5V TO 36V OFF ON 0.1μF D3, 6V 47μH 10k 86.6k 10μF
1933 TA02d
2.2μF VOUT 12V/ 450mA VIN BOOST GND FB SHDN SW L T1933
3.00 ±0.10 (2 SIDES) 2.00 ±0.10 (2 SIDES) NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (TBD) 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 1.65 ± 0.10 (2 SIDES) 0.75 ±0.05 R = 0.115 TYP R = 0.05 TYP 1.35 ±0.10 (2 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6)
0.200 REF
0.00 – 0.05 (DCB6) DFN 0405 0.25 ± 0.05
0.50 BSC
R0.20 OR 0.25 × 45° CHAMFER 0.25 ± 0.05 1.35 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.65 ±0.05 (2 SIDES) 2.15 ±0.05 0.70 ±0.05 3.55 ±0.05 PACKAGE OUTLINE 6-Lead Plastic DFN (2mm × 3mm) (Reference L TC DWG # 05-08-1715)
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. 1.50 – 1.75 0.25 – 0.50 TYP 6 PLCS NOTE 3 DATUM ‘A’ 0.09 – 0.20 (NOTE 3) S6 SOT-23 0502 2.80 – 3.10 (NOTE 4)
0.95 BSC
1.90 BSC
0.90 – 1.30 0.90 – 1.45 0.09 – 0.15 NOTE 3
0.20 BSC
0.35 – 0.55 REF PIN ONE ID NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ) ATTENTION: ORIGINAL SOT23-6L PACKAGE. MOST SOT23-6L PRODUCTS CONVERTED TO THIN SOT23 PACKAGE, DRAWING # 05-08-1636 AFTER APPROXIMATEL Y APRIL 2001 SHIP DATE
3.85 MAX
0.62 MAX 0.95 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 1.4 MIN2.62 REF
1.22 REF
(Reference L TC DWG # 05-08-1634)
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 0108 REV D • PRINTED IN USA RELATED PARTS TYPICAL APPLICATION PART NUMBER DESCRIPTION COMMENTS L T1074/L T1074HV 4.4A I OUT, 100kHz, High Effi ciency Step-Down DC/DC Converter VIN: 7.3V to 45V/64V , VOUT(MIN) = 2.21V , IQ = 8.5mA, ISD = 10μA, DD-5/DD-7, TO220-5/TO220-7 Packages L T1076/L T1076HV 1.6A I OUT, 100kHz, High Effi ciency Step-Down DC/DC Converter VIN: 7.3V to 45V/64V , VOUT(MIN) = 2.21V , IQ = 8.5mA, ISD = 10μA, DD-5/DD-7, TO220-5/TO220-7 Packages L T1676 60V , 440mA I OUT, 100kHz, High Effi ciency Step-Down DC/DC Converter VIN: 7.4V to 60V , VOUT(MIN) = 1.24V , IQ = 3.2mA, ISD = 2.5μA, L T1765 25V , 2.75mA I OUT, 1.25MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V , VOUT(MIN) = 1.2V , IQ = 1mA, ISD = 15μA, S8, TSSOP16E Packages L T1766 60V , 1.2A I OUT, 200kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V , VOUT(MIN) = 1.2V , IQ = 2.5mA, ISD = 25μA, S8, TSSOP16/TSSOP16E Packages L T1767 25V , 1.2A I OUT, 1.25MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V , VOUT(MIN) = 1.2V , IQ = 1mA, ISD = 6μA, S8, MS8/MS8E Packages L T1776 40V , 550mA I OUT, 200kHz, High Effi ciency Step-Down DC/DC Converter VIN: 7.4V to 40V , VOUT(MIN) = 1.24V , IQ = 3.2mA, ISD = 30μA, S8, N8, S8 Packages L T1940 25V , Dual 1.4A I OUT, 1.1MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3.6V to 25V , VOUT(MIN) = 1.25V , IQ = 3.8mA, ISD = <30μA, L T1956 60V , Dual 1.2A I OUT, 500kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V , VOUT(MIN) = 1.2V , IQ = 2.5mA, ISD = 25μA, TSSOP16/TSSOP16E Packages L T1976 60V , Dual 1.2A I OUT, 200kHz, High Effi ciency Step-Down DC/DC Converter with Burst Mode VIN: 3.3V to 60V , VOUT(MIN) = 1.2V , IQ = 100μA, ISD = <1μA, L T3010 80V , 50mA, Low Noise Linear Regulator V IN: 1.5V to 80V , VOUT(MIN) = 1.28V , IQ = 30μA, ISD = <1μA, L T3407 Dual 600mA I OUT, 1.5MHz, Synchronous Step-Down DC/DC Converter VIN: 2.5V to 5.5V , VOUT(MIN) =0.6V , IQ = 40μA, ISD = <1μA, L T3412 2.5A I OUT, 4MHz, Synchronous Step-Down DC/DC Converter VIN: 2.5V to 5.5V , VOUT(MIN) =0.8V , IQ = 60μA, ISD = <1μA, L TC3414 4A I OUT, 4MHz, Synchronous Step-Down DC/DC Converter V IN: 2.3V to 5.5V , VOUT(MIN) =0.8V , IQ = 64μA, ISD = <1μA, L T3430/L T3431 60V , 2.75A I OUT, 200kHz/500kHz, Synchronous Step-Down DC/DC Converter VIN: 5.5V to 60V , VOUT(MIN) =1.2V , IQ = 2.5mA, ISD = 30μA, Burst Mode is a registered trademark of Linear Technology Corporation. 2.5V Step-Down Converter VIN 3.6V TO 36V OFF ON 0.47μF 15μH 10k 10.5k 22μF
1933 TA03
2.2μF VOUT 2.5V/500mA VIN BOOST GND FB SHDN SW L T1933