T1074HV

LT1074 LINER

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Technical content

, LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO SU

FEATURES

1074 is a 5A (LT1076 is rated at 2A) monolithic bipolar switching regulator which requires only a few external parts for normal operation. The power switch, all oscillator and control circuitry, and all current limit com- ponents, are included on the chip. The topology is a classic n Buck Converter with Output Voltage Range of 2.5V to 50V n Tapped-Inductor Buck Converter with 10A Output at 5V n Positive-to-Negative Converter n Negative Boost Converter n Multiple Output Buck Converter n 5A Onboard Switch (LT1074) n 100kHz Switching Frequency n Greatly Improved Dynamic Behavior n Available in Low Cost 5 and 7-Lead Packages n Only 8.5mA Quiescent Current n Programmable Current Limit n Operates Up to 60V Input n Micropower Shutdown Mode positive “buck” configuration but several design innova- tions allow this device to be used as a positive-to-negative converter, a negative boost converter, and as a flyback converter. The switch output is specified to swing 40V below ground, allowing the LT1074 to drive a tapped- inductor in the buck mode with output currents up to 10A. The LT1074 uses a true analog multiplier in the feedback loop. This makes the device respond nearly instanta- neously to input voltage fluctuations and makes loop gain independent of input voltage. As a result, dynamic behav- ior of the regulator is significantly improved over previous designs. On-chip pulse by pulse current limiting makes the LT1074 nearly bust-proof for output overloads or shorts. The input voltage range as a buck converter is 8V to 60V, but a self- boot feature allows input voltages as low as 5V in the inverting and boost configurations. The LT1074 is available in low cost TO-220 or TO-3 packages with frequency pre-set at 100kHz and current limit at 6.5A (LT1076 = 2.6A). A 7-pin TO-220 package is also available which allows current limit to be adjusted down to zero. In addition, full micropower shutdown can be programmed. See Application Note 44 for design details. A fixed 5V output, 2A version is also available. See LT1076-5. Buck Converter Efficiency Basic Positive Buck Converter + + VSWVIN VCGND FB LT1074 500µF 2.8k 2.21k MBR745* 10V TO 40V 200µF 2.7k 0.01µF L1** 50µH (LT1074) 100µH (LT1076) USE MBR340 FOR LT1076 COILTRONICS #50-2-52 (LT1074) #100-1-52 (LT1076) PULSE ENGINEERING, INC. #PE-92114 (LT1074) #PE-92102 (LT1076) HURRICANE #HL-AK147QQ (LT1074) #HL-AG210LL (LT1076) RIPPLE CURRENT RATING ‡ I OUT/2 LT1074•TA01 25V OUTPUT LOAD CURRENT (A) EFFICIENCY (%) 123 4 LT1074•TPC27 5 6 100 L = 50µH TYPE 52 CORE DIODE = MBR735 V = 5V, V = 15VOUT IN V = 12V, V = 20VOUT IN LT1074

ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W (Note 1) *Assumes package is soldered to 0.5 IN2 of 1 oz. copper over internal ground plane or over back side plane. LT1076CQ LT1076IQ LT1076CR LT1076IR LT1076HVCR LT1076HVIR LT1074CT7 LT1074HVCT7 LT1074IT7 LT1074HVIT7 LT1076CT7 LT1076HVCT7 LT1074CT LT1074HVCT LT1074IT LT1074HVIT LT1076CT LT1076HVCT LT1076IT LT1076HVIT LT1074CK LT1074HVCK LT1074MK LT1074HVMK LT1076CK LT1076HVCK LT1076MK LT1076HVMK Input Voltage Switch Voltage with Respect to Input Voltage Switch Voltage with Respect to Ground Pin (VSW Negative) Maximum Operating Ambient Temperature Range Maximum Operating Junction Temperature Range ORDER PART NUMBER ORDER PART NUMBER LT1076: qJC = 4°C, qJA = 30°C/W LT1076: qJC = 4°C, qJA = 30°C/W LT1074: qJC = 2.5°C, qJA = 50°C/W LT1076: qJC = 4°C, qJA = 50°C/W LT1074: qJC = 2.5°C, qJA = 35°C/W LT1076: qJC = 4°C, qJA = 35°C/W LT1074: qJC = 2.5°C, qJA = 50°C/W LT1076: qJC = 4°C, qJA = 50°C/W Q PACKAGE 5-LEAD PLASTIC DD FRONT VIEW VIN VSW GND VC FB/SENSE R PACKAGE 7-LEAD PLASTIC DD FRONT VIEW SHDN V C FB/SENSE GND I LIM VSW VIN VC VIN VSW CASE IS GND FB K PACKAGE 4-LEAD TO-3 METAL CAN BOTTOM VIEW T PACKAGE 5-LEAD PLASTIC TO-220 LEADS ARE FORMED STANDARD FOR STRAIGHT LEADS, ORDER FLOW 06 VIN VSW GND VC FB FRONT VIEW T7 PACKAGE 7-LEAD PLASTIC TO-220 SHDN VC FB GND I LIM VSW VIN FRONT VIEW TAB IS GND TAB IS GND TAB IS GND TAB IS GND

The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Tj = 25°C, VIN = 25V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Switch “On” Voltage (Note 2) LT1074 I SW = 1A, Tj ‡ 0°C 1.85 V ISW = 1A, Tj < 0°C 2.1 V ISW = 5A, Tj ‡ 0°C 2.3 V ISW = 5A, Tj < 0°C 2.5 V LT1076 I SW = 0.5A l 1.2 V ISW = 2A l 1.7 V Switch “Off” Leakage LT1074 V IN £ 25V, VSW = 0 5 300 mA VIN = VMAX, VSW = 0 (Note 8) 10 500 mA LT1076 V IN = 25V, VSW = 0 150 mA VIN = VMAX, VSW = 0 (Note 8) 250 mA Supply Current (Note 3) V FB = 2.5V, VIN £ 40V l 8.5 11 mA 40V < VIN < 60V l 91 2 m A VSHUT = 0.1V (Device Shutdown) (Note 9) l 140 300 mA Minimum Supply Voltage Normal Mode l 7.3 8 V Startup Mode (Note 4) l 3.5 4.8 V Switch Current Limit (Note 5) LT1074 I LIM Open l 5.5 6.5 8.5 A RLIM = 10k (Note 6) 4.5 A RLIM = 7k (Note 6) 3 A LT1076 I LIM Open l 2 2.6 3.2 A RLIM = 10k (Note 6) 1.8 A RLIM = 7k (Note 6) 1.2 A Maximum Duty Cycle l 85 90 % Switching Frequency 90 100 110 kHz Tj £ 125°C l 85 120 kHz Tj > 125°C l 85 125 kHz VFB = 0V through 2kW (Note 5) 20 kHz Switching Frequency Line Regulation 8V £ VIN £ VMAX (Note 8) l 0.03 0.1 %/V Error Amplifier Voltage Gain (Note 7) 1V £ VC £ 4V 2000 V/V Error Amplifier Transconductance 3700 5000 8000 mmho Error Amplifier Source and Sink Current Source (V FB = 2V) 100 140 225 mA Sink (VFB = 2.5V) 0.7 1 1.6 mA Feedback Pin Bias Current V FB = VREF l 0.5 2 mA Reference Voltage V C = 2V l 2.155 2.21 2.265 V Reference Voltage Tolerance V REF (Nominal) = 2.21V –0.5 –1.5 % All Conditions of Input Voltage, Output l –1 –2.5 % Voltage, Temperature and Load Current Reference Voltage Line Regulation 8V £ VIN £ VMAX (Note 8) l 0.005 0.02 %/V VC Voltage at 0% Duty Cycle 1.5 V Over Temperature l –4 mV/ °C Multiplier Reference Voltage 24 V Shutdown Pin Current V SH = 5V l 51 0 2 0 mA VSH £ VTHRESHOLD (@2.5V) l 50 mA Shutdown Thresholds Switch Duty Cycle = 0 l 2.2 2.45 2.7 V Fully Shut Down l 0.1 0.3 0.5 V Thermal Resistance Junction to Case LT1074 2.5 °C/W LT1076 4.0 °C/W

ELECTRICAL CHARACTERISTICS

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: To calculate maximum switch “on” voltage at currents between low and high conditions, a linear interpolation may be used. Note 3: A feedback pin voltage (VFB) of 2.5V forces the VC pin to its low clamp level and the switch duty cycle to zero. This approximates the zero load condition where duty cycle approaches zero. Note 4: Total voltage from V IN pin to ground pin must be ‡ 8V after start- up for proper regulation. Note 5: Switch frequency is internally scaled down when the feedback pin voltage is less than 1.3V to avoid extremely short switch on times. During testing, VFB is adjusted to give a minimum switch on time of 1ms. Note 6: ILIM » (LT1074), ILIM » (LT1076). Note 7: Switch to input voltage limitation must also be observed. Note 8: VMAX = 40V for the LT1074/76 and 60V for the LT1074HV/76HV. Note 9: Does not include switch leakage. RLIM – 1k RLIM – 1k 5.5k -POWER SHUTDOWN µ

10 Aµ 320 Aµ

2.35V 0.3V CURRENT LIMIT SHUTDOWN 4.5V 10k S CURRENT LIMIT COMP 15400+ R/S LATCH R R Q X Y ERROR AMP FB V 100kHz OSCILLATOR ANALOG MULTIPLIER XY Z FREQ SHIFT SYNC PULSE WIDTH COMPARATOR 24V (EQUIVALENT) 2.21V SWITCH OUTPUT (V ) 0.04 250 500 INPUT SUPPLY SHUTDOWN* I * 6V TO ALL CIRCUITRY LIM Ω Ω SW Ω Ω VIN C LT1074 • BD01 100 SWITCH OUTPUT (V ) 0.1 Ω SW Ω 3V(p-p) LT1076 LT1074 *AVAILABLE ON PACKAGES WITH PIN COUNTS GREATER THAN 5. BLOCK DIAGRA W

A switch cycle in the LT1074 is initiated by the oscillator setting the R/S latch. The pulse that sets the latch also locks out the switch via gate G1. The effective width of this pulse is approximately 700ns, which sets the maximum switch duty cycle to approximately 93% at 100kHz switch- ing frequency. The switch is turned off by comparator C1, which resets the latch. C1 has a sawtooth waveform as one input and the output of an analog multiplier as the other input. The multiplier output is the product of an internal reference voltage, and the output of the error amplifier, A1, divided by the regulator input voltage. In standard buck regulators, this means that the output voltage of A1 required to keep a constant regulated output is indepen- dent of regulator input voltage. This greatly improves line transient response, and makes loop gain independent of input voltage. The error amplifier is a transconductance type with a G M at null of approximately 5000mmho. Slew current going positive is 140 mA, while negative slew current is about 1.1mA. This asymmetry helps prevent overshoot on start-up. Overall loop frequency compensa- tion is accomplished with a series RC network from V C to ground. Switch current is continuously monitored by C2, which resets the R/S latch to turn the switch off if an overcurrent condition occurs. The time required for detection and switch turn off is approximately 600ns. So minimum switch “on” time in current limit is 600ns. Under dead shorted output conditions, switch duty cycle may have to be as low as 2% to maintain control of output current. This would require switch on time of 200ns at 100kHz switch- ing frequency, so frequency is reduced at very low output voltages by feeding the FB signal into the oscillator and creating a linear frequency downshift when the FB signal drops below 1.3V. Current trip level is set by the voltage on the I LIM pin which is driven by an internal 320mA current source. When this pin is left open, it self-clamps at about 4.5V and sets current limit at 6.5A for the LT1074 and 2.6A for the LT1076. In the 7-pin package an external resistor can be connected from the I LIM pin to ground to set a lower current limit. A capacitor in parallel with this resistor will soft-start the current limit. A slight offset in C2 guarantees that when the I LIM pin is pulled to within 200mV of ground, C2 output will stay high and force switch duty cycle to zero. The “Shutdown” pin is used to force switch duty cycle to zero by pulling the ILIM pin low, or to completely shut down the regulator. Threshold for the former is approximately 2.35V, and for complete shutdown, approximately 0.3V. Total supply current in shutdown is about 150mA. A 10mA pull-up current forces the shutdown pin high when left open. A capacitor can be used to generate delayed start- up. A resistor divider will program “undervoltage lockout” if the divider voltage is set at 2.35V when the input is at the desired trip point. The switch used in the LT1074 is a Darlington NPN (single NPN for LT1076) driven by a saturated PNP. Special patented circuitry is used to drive the PNP on and off very quickly even from the saturation state. This particular switch arrangement has no “isolation tubs” connected to the switch output, which can therefore swing to 40V below ground. BLOCK DIAGRA WDESCRIPTIO U

Shutdown Pin Characteristics VC Pin Characteristics V C Pin Characteristics Feedback Pin Characteristics Shutdown Pin Characteristics I LIM Pin Characteristics TYPICAL PERFOR A CE CHARACTERISTICSUW –150 CURRENT (mA) 100 150 200 1234 LT1074•TPC01 –200 –100 5 6 789 VOLTAGE (V) –50 V ≤ 2VFB SLOPE ≈ 400kΩ V ADJUSTED FOR I = 0 AT V = 2V FB CC –1.5 CURRENT (mA)–0.5 0.5 1.0 1.5 2.0 1234 LT1074•TPC02 –2.0 –1.0 5 6 789 V ‡ 2.5V FB VOLTAGE (V) –400 CURRENT (µA) –200 1 234 LT1074•TPC03 –500 –300 5 6 78 1 0 9 –100 100 200 300 400 500 VOLTAGE (V) START OF FREQUENCY SHIFTING VOLTAGE (V) –40 CURRENT (µA) 20 40 LT1074•TPC04 30 50 60 70 80 –30 –20 –10 VIN = 50V THIS POINT MOVES INWITH V DETAILS OF THIS AREA SHOWN IN OTHER GRAPH VOLTAGE (V) –40 CURRENT (µA) 1.0 2.0 LT1074•PC05 –35 –30 –25 –20 –15 –10 SHUTDOWN THRESHOLD CURRENT FLOWS OUT OF SHUTDOWN PIN = 25°CTj 0.5 –2 –350 CURRENT (µA) –250 –150 0 12 LT1074•TPC06 –400 –300 3 4 5 –200 –100 –50 100 VOLTAGE (V) –1 6 7 8 T = 25°Cj INPUT VOLTAGE (V) INPUT CURRENT (mA) 20 30 60 LT1074•TPC11 10 40 50 V C = 1V DEVICE NOT SWITCHING

Reference Shift with Ripple Voltage Feedback Pin Frequency Shift Supply Current (Shutdown) Reference Voltage vs Temperature Switch “On” Voltage Error Amplifier Phase and GM Switching Frequency vs Temperature Current Limit vs Temperature* TYPICAL PERFOR A CE CHARACTERISTICSUW INPUT VOLTAGE (V) INPUT CURRENT (µA) 100 150 200 250 300 30 50 60 LT1074•TPC13 10 20 40 JUNCTION TEMPERATURE (°C) –50 2.19 VOLTAGE (V)2.20 2.21 2.22 2.23 2.24 2.25 –25 0 25 50 LT1074•TPC14 2.18 2.17 75 100 125 150 0 “ON” VOLTAGE (V) 3.0 2.5 2.0 1.5 1.0 0.5 123 LT1074•TPC28 4 56 SWITCH CURRENT (A) T = 25°Cj LT1074 LT1076 SQUARE WAVE PEAK-TO-PEAK RIPPLE AT FB PIN (mV) –80 CHANGE IN REFERENCE VOLTAGE (mV)–70 –60 –50 –40 –30 20 40 60 80 LT1074•TPC16 100 120 140 160 180 200 –20 –10 TRI WAVE FREQUENCY (Hz) (µmho) 1k 100k 1M 10M 10k TRANSCONDUCTANCE 200 150 100 –50 PHASE (°) q MG –100 –150 –200 LT1074•TPC17 JUNCTION TEMPERATURE (°C) –50 FREQUENCY (kHz) 100 105 110 115 120 –25 0 25 50 LT1074•TPC18 75 100 125 150 FEEDBACK PIN VOLTAGE (V) SWITCHING FREQUENCY (kHz) 1.0 1.5 3.0 LT1074•TPC19 0.5 2.0 2.5 160 100 120 140 –55°C 25°C 150°C JUNCTION TEMPERATURE (°C) LT1074•TPC22 –50 –25 0 25 50 75 100 125 150 OUTPUT CURRENT LIMIT (A) *MULTIPLY CURRENTS BY 0.4 FOR LT1076 I PIN OPENLIM R = 10kΩLIM R = 5kΩLIM

Figure 1. Input Capacitor Ripple Figure 2. Proper Ground Pin Connection inductance. Use radial lead capacitors. more sensitive to large ripple voltages at the feedback pin. output divider is connected. See the “Error Amplifier” section for more details. special testing if shutdown mode input current is critical.

Figure 5. Shutdown Circuitry Figure 6. Undervoltage Lockout Figure 7. Adding Hysteresis Undervoltage lockout point is set by R1 and R2 in Figure␣ 6. should replace VSH with VSH – (10mA)(R2).

10 Aµ 300 Aµ

shutdown divider from altering current limit. to operate until VIN drops to 15V. Let R2 = 2.32k.

Figure 10. Error Amplifier input) when the reactance of CC is small compared to RC. frequency “zero” is determined solely by RC and CC. The error amplifier has asymmetrical peak output current. by area scaling Q1 and Q2 at 1.8:1.

Tapped-Inductor Buck Converter Positive-to-Negative Converter with 5V Output TYPICAL APPLICATIO SU VSWVIN VCGND FB LT1074HV R1 2.8k 2.21k 35V 200 µF 50V 0.2µF L1* LT1074 •TA02 D1** 1N5819 4400µF (2 EA 2200 µF, 16V) 5µH 390 µF 16V 0.01µF PULSE ENGINEERING #PE–65282* MOTOROLA MBR2030CTL IF INPUT VOLTAGE IS BELOW 20V, MAXIMUM OUTPUT CURRENT WILL BE REDUCED. SEE AN44 V IN 20V† TO 35V VOUT 5V, 10A† R3* 2.74kVIN VSW VGND 1.82k* 1000µF 10V 25µH 5A†† D1† MBR745 R1 5.1k VC 0.1 µF C4 0.01 µF R2** 10k 220 µF 50V * = 1% FILM RESISTORS D1 = MOTOROLA-MBR745 C1 = NICHICON-UPL1C221MRH6 C2 = NICHICON-UPL1A102MRH6 L1 = COILTRONICS-CTX25-5-52 V 4.5V to 40V IN –5V,1A*** 200µF 10V OPTIONAL FILTER 5µH LOWER REVERSE VOLTAGE RATING MAY BE USED FOR LOWER INPUT VOLTAGES. LOWER CURRENT RATING IS ALLOWED FOR LOWER OUTPUT CURRENT. SEE AN44. R1, R2, AND C4 ARE USED FOR LOOP FREQUENCY COMPENSATION WITH LOW INPUT VOLTAGE, BUT R1 AND R2 MUST BE INCLUDED IN THE CALCULATION FOR OUTPUT VOLTAGE DIVIDER VALUES. LOWER CURRENT RATING MAY BE USED FOR LOWER OUTPUT CURRENT. SEE AN44. R3 = –2.37 (KΩ ) R1 = (R3) (1.86) R2 = (R3) (3.65) V OUT MAXIMUM OUTPUT CURRENT OF 1A IS DETERMINED BY MINIMUM INPUT VOLTAGE OF 4.5V. HIGHER MINIMUM INPUT VOLTAGE WILL ALLOW MUCH HIGHER OUTPUT CURRENTS. SEE AN44. LT1074 • TA03 LT1074 FB FOR HIGHER OUTPUT VOLTAGES, INCREASE R1, R2, AND R3 PROPORTIONATELY. FOR INPUT VOLTAGE > 10V, R1, R2, AND C4 CAN BE ELIMINATED, AND COMPENSATION IS DONE TOTALLY ON THE V PIN. C

(LTC DWG # 05-08-1311) Q Package 5-Lead Plastic DD Pak (LTC DWG # 05-08-1461) PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. K4(TO-3) 1098 72° 18° 0.490 – 0.510 (12.45 – 12.95) R 0.470 TP P.C.D. 0.167 – 0.177 (4.24 – 4.49) R 0.151 – 0.161 (3.84 – 4.09) DIA 2 PLC 0.655 – 0.675 (16.64 – 19.05) 1.177 – 1.197 (29.90 – 30.40) 0.038 – 0.043 (0.965 – 1.09) 0.060 – 0.135 (1.524 – 3.429) 0.320 – 0.350 (8.13 – 8.89) 0.420 – 0.480 (10.67 – 12.19) 0.760 – 0.775 (19.30 – 19.69) Q(DD5) 1098 0.028 – 0.038 (0.711 – 0.965) 0.143 +0.012 –0.020 ()3.632 +0.305 –0.508 0.067 (1.70) BSC 0.013 – 0.023 (0.330 – 0.584) 0.095 – 0.115 (2.413 – 2.921) 0.004+0.008 –0.004 ()0.102+0.203 –0.102 0.050 – 0.012 (1.270 – 0.305) 0.059 (1.499) TYP 0.045 – 0.055 (1.143 – 1.397) 0.165 – 0.180 (4.191 – 4.572) 0.330 – 0.370 (8.382 – 9.398) 0.060 (1.524) TYP 0.390 – 0.415 (9.906 – 10.541) 15° TYP 0.300 (7.620) 0.075 (1.905) 0.183 (4.648) 0.060 (1.524) 0.060 (1.524) 0.256 (6.502) BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK

5-Lead Plastic TO-220 (Standard) (LTC DWG # 05-08-1421) R Package 7-Lead Plastic DD Pak (LTC DWG # 05-08-1462) PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. R (DD7) 1098 0.026 – 0.036 (0.660 – 0.914) 0.143 +0.012 –0.020 ()3.632 +0.305 –0.508 0.050 (1.27) BSC 0.013 – 0.023 (0.330 – 0.584) 0.095 – 0.115 (2.413 – 2.921) 0.004+0.008 –0.004 ()0.102 +0.203 –0.102 0.050 – 0.012 (1.270 – 0.305) 0.059 (1.499) TYP 0.045 – 0.055 (1.143 – 1.397) 0.165 – 0.180 (4.191 – 4.572) 0.330 – 0.370 (8.382 – 9.398) 0.060 (1.524) TYP 0.390 – 0.415 (9.906 – 10.541) 15° TYP 0.300 (7.620) 0.075 (1.905) 0.183 (4.648) 0.060 (1.524) 0.060 (1.524) 0.256 (6.502) BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK T5 (TO-220) 0399 0.028 – 0.038 (0.711 – 0.965) 0.067 (3.429 – 4.191) 0.700 – 0.728 (17.78 – 18.491) 0.045 – 0.055 (1.143 – 1.397) 0.095 – 0.115 (2.413 – 2.921) 0.013 – 0.023 (0.330 – 0.584) 0.620 (15.75) TYP 0.155 – 0.195* (3.937 – 4.953) 0.152 – 0.202 (6.60 – 8.13) 0.165 – 0.180 (4.191 – 4.572) 0.147 – 0.155 (3.734 – 3.937) DIA 0.390 – 0.415 (9.906 – 10.541) 0.330 – 0.370 (8.382 – 9.398) 0.460 – 0.500 (11.684 – 12.700) 0.570 – 0.620 (14.478 – 15.748) 0.230 – 0.270 (5.842 – 6.858) BSC SEATING PLANE * MEASURED AT THE SEATING PLANE 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear-tech.com ª LINEAR TECHNOLOGY CORPORATION 1 994 1074fc LT/TP 0100 2K REV C • PRINTED IN USA RELATED PARTS PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. TYPICAL APPLICATIO U PART NUMBER DESCRIPTION COMMENTS LT1375/LT1376 1.5A, 500kHz Step-Down Switching Regulators V IN Up to 25V, IOUT Up to 1.25A, SO-8 LT1374/LT1374HV 4.5A, 500kHz Step-Down Switching Regulators V IN Up to 25V (32V for HV), IOUT Up to 4.25A, SO-8/DD LT1370 6A, 500kHz High Efficiency Switching Regulator 6A/42V Internal Switch, 7-Lead DD/TO-220 LT1676 Wide Input Range, High Efficiency Step-Down Regulator V IN from 7.4V to 60V, IOUT Up to 0.5A, SO-8 LT1339 High Power Synchronous DC/DC Controller V IN Up to 60V, IOUT Up to 50A, Current Mode Negative Boost Converter 7-Lead Plastic TO-220 (Standard) (LTC DWG # 05-08-1422) 0.050 (1.27) 0.026 – 0.036 (0.660 – 0.914) T7 (TO-220) 0399 0.135 – 0.165 (3.429 – 4.191) 0.700 – 0.728 (17.780 – 18.491) 0.045 – 0.055 (1.143 – 1.397) 0.165 – 0.180 (4.191 – 4.572) 0.095 – 0.115 (2.413 – 2.921) 0.013 – 0.023 (0.330 – 0.584) 0.620 (15.75) TYP 0.155 – 0.195* (3.937 – 4.953) 0.152 – 0.202 (6.604 – 8.128) 0.147 – 0.155 (3.734 – 3.937) DIA 0.390 – 0.415 (9.906 – 10.541) 0.330 – 0.370 (8.382 – 9.398) 0.460 – 0.500 (11.684 – 12.700) 0.570 – 0.620 (14.478 – 15.748) 0.230 – 0.270 (5.842 – 6.858) BSC SEATING PLANE *MEASURED AT THE SEATING PLANE 12.7k VIN VFB VGND 2.21k 1000µF 25VL1 25µH +C3 200µF 15V D1* 750Ω VC 0.01µF 100pF 1nF VOUT –15V**VIN –5V TO –15V MBR735 IOUT (MAX) = 1A TO 3A DEPENDING ON INPUT VOLTAGE. SEE AN44 LT1074 • TA04 LT1074 SW 100µF OPTIONAL OUTPUT FILTER 5µH