3433EFE

LT3433 LINER

Document overview

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Technical content

n Automatic Step-Up and Step-Down Conversion n Uses a Single Inductor n Wide 4V to 60V Input Voltage Range n VOUT from 3.3V to 20V n Dual Internal 500mA Switches n 100mA No-Load Quiescent Current n Low Current Shutdown n –1% Output Voltage Accuracy n 200kHz Operating Frequency n Boosted Supply Pin to Saturate High Side Switch n Frequency Foldback Protection n Current Limit Foldback Protection n Current Limit Unaffected by Duty Cycle n 16-lead Thermally Enhanced TSSOP Package n 12V Automotive Systems n Wall Adapter Powered Systems n Battery Power Voltage Buffering , LTC and LT are registered trademarks of Linear Technology Corporation. FEATURES DESCRIPTIONU APPLICATIO SU TYPICAL APPLICATIO U Burst Mode is a registered trademark of Linear Technology Corporation. The LT 3433 is a 200kHz fixed-frequency current mode switching regulator that provides both step-up and step- down regulation using a single inductor. The IC operates over a 4V to 60V input voltage range making it suitable for use in various wide input voltage range applications such as automotive electronics that must withstand both load dump and cold crank conditions. Internal control circuitry monitors system conditions and converts from single switch buck operation to dual switch bridged operation when required, seamlessly changing between step-down and step-up voltage conversion. Optional Burst Mode operation reduces no-load quies- cent current to 100mA and maintains high efficiencies with light loads. Current limit foldback and frequency foldback help pre- vent inductor current runaway during start-up. Program- mable soft-start helps prevent output overshoot at start-up. The LT3433 is available in a 16-lead thermally enhanced TSSOP package. VBST SW_H VIN BURST_EN V C VFB SW_L PWRGND VOUT VBIAS SHDN SS SGND LT3433 1N4148 0.1µF 68k 100k 0.5% 305k 0.5% 1nF100pF 2.2µF VIN 4V TO 60V 0.01µF

3433 TA01

0.1µF 1N4148 100µH CoEv DU1352-101M B120A 47µF VOUT 4V ≤ VIN ≤ 8.5V: 125mA 8.5V ≤ VIN ≤ 60V: 350mA B160A 4V to 60V to 5V DC/DC Converter with Burst Mode Operation Final Electrical Specifications 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. OUTPUT CURRENT (mA) EFFICIENCY (%) 0.1 10 100 1000

3433 TA01b

VIN = 13.8V VIN = 4V Efficiency VIN (V) MAXIMUM OUTPUT CURRENT (mA) 100 200 300 400 500 10 20 30 40

3433 TA01c

VOUT = 5V Maximum Output Current vs VIN

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Operating Voltage Range l 46 0 V VIN(UVLO) Undervoltage Lockout Enable Threshold l 3.4 3.95 V Undervoltage Lockout Hysteresis 160 mV VOUT Operating Voltage Range l 3.3 20 V VBST Operating Voltage Range V BST < VSW_H + 20V l 75 V VBST – VSW_H l 3.3 20 V IVIN Normal Operation (Notes 2, 3) l 580 940 mA Burst Mode Operation V VC < 0.6V l 100 190 mA Shutdown V SHDN < 0.4V l 10 25 mA VBIAS Internal Supply Output Voltage l 2.6 2.9 V Operating Voltage Range l 20 V IVBIAS Normal Operation l 660 990 mA Burst Mode Operation V VC < 0.6V 0.1 mA Shutdown V SHDN < 0.4V 0.1 mA Short-Circuit Current Limit 4.5 mA RSWH(ON) Boost Supply Switch On-Resistance I SW = 500mA l 0.8 1.2 W RSWL(ON) Output Supply Switch On-Resistance I SW = 500mA l 0.6 1 W VSHDN Shutdown Pin Thresholds Disable l 0.4 V Enable l 1V IVBST/ISW Boost Supply Switch Drive Current High Side Switch On, I SW = 500mA l 30 50 mA/A IVOUT/ISW Output Supply Switch Drive Current Low Side Switch On, I SW = 500mA l 30 50 mA/A ILIM Switch Current Limit l 0.5 0.7 0.9 A Foldback Current Limit V FB = 0V 0.35 A ISS Soft-Start Output Current l 359 mA VFB Feedback Reference Voltage 1.224 1.231 1.238 V l 1.215 1.245 V (Note 1) (VBST(MAX) = 80V) Feedback Voltage (V Operating Junction Temperature Range (Note 5) ABSOLUTE MAXIMUM RATINGSW WW U PACKAGE/ORDER INFORMATIONW UU ORDER PART NUMBER LT3433EFE LT3433IFE FE PART MARKING 3433EFE 3433IFE TJMAX = 125°C, qJA = 40°C/W, qJC = 10°C/W EXPOSED PAD (PIN 17) MUST BE SOLDERED TO SGND The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 13.8V, VFB = 1.25V, VOUT = 5V, VBURST_EN = 0V, VBST – VIN = 5V, unless otherwise noted. Consult LTC Marketing for parts specified with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS

V BST SW_H VIN BURST_EN VC VFB SGND SGND SW_L PWRGND V OUT VBIAS SHDN SS SGND

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS DVFB Feedback Reference Line Regulation 5.5V £ VIN £ 60V l 0.002 0.01 %/V IFB VFB Pin Input Bias Current l 35 100 nA gm Error Amplifier Transconductance l 200 270 330 umhos AV Error Amplifier Voltage Gain 66 dB ISW/VVC Control Voltage to Switch Transconductance 0.55 A/V fO Operating Frequency V FB > 1V 185 200 215 kHz l 170 230 kHz Foldback Frequency V FB = 0V 50 kHz tON(MIN) Minimum Switch On Time R L = 35W (Note 4) l 250 450 ns tOFF(MIN) Minimum Switch Off Time R L = 35W (Note 4) l 500 800 ns The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 13.8V, VFB = 1.25V, VOUT = 5V, VBURST_EN = 0V, VBST – VIN = 5V, unless otherwise noted. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Supply current specification does not include switch drive currents. Actual supply currents will be higher. Note 3: “Normal Operation” supply current specification does not include IBIAS currents. Powering the VBIAS pin externally reduces ICC supply current. Note 4: Minimum times are tested using the high side switch with a 35W load to ground. Note 5: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 6: The LT3433E 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 LT3433I is guaranteed over the full –40°C to 125°C operating junction temperature range. TYPICAL PERFOR A CE CHARACTERISTICS UW TEMPERATURE (°C) –50 2.2 VBIAS OUTPUT VOLTAGE (V)2.4 2.6 2.8 05 0

3433 G01

VIN (V) IVIN (µA) 620 590 560 530 500

3433 G02

TA = 25°C VIN (V) MAXIMUM OUTPUT CURRENT (mA) 100 200 300 400 500 10 20 30 40

3433 G11

V OUT = 5V Maximum Output Current vs VIN

TEMPERATURE (°C) –50 OSCILLATOR FREQUENCY (kHz) 210 205 200 195 190 05 0

3433 G06

VFB (V) OSCILLATOR FREQUENCY (kHz) 100 150 0.8

3433 G07

0.2 0.4 0.6 1.0 200 TA = 25°C TYPICAL PERFOR A CE CHARACTERISTICS UW Error Amp Reference vs Temperature Switch Current Limit vs VFB TEMPERATURE (°C) –50 1.228 1.229ERROR AMP REFERENCE (V) 1.230 1.231 1.232 05 0

3433 G04

VFB (V) SWITCH CURRENT LIMIT (mA) 500 600 0.8

3433 G05

0.2 0.4 0.6 1.0 700 TA = 25°C Oscillator Frequency vs Temperature Oscillator Frequency vs VFB TEMPERATURE (°C) –50 CURRENT LIMIT (mA) 750 725 700 675 650 05 0

3433 G08

Maximum Boost Supply Switch Drive Current vs Boost Supply Voltage VBST – VSW_H (V) IBST/ISW (mA/A) 79 1 2

3433 G09

Maximum Output Supply Switch Drive Current vs Output Supply Voltage VOUT (V) IVOUT/ISW (mA/A) 79 1 2

3433 G10

Soft-Start Current vs Temperature TEMPERATURE (°C) ISS (µA) 7.0 6.5 6.0 5.5 5.0 4.5 4.0

3433 G03

–50 0 50 100 125

VFB (Pin 7): Error Amplifier Inverting Input. The noninvert- ing input of the error amplifier is connected to an internal 1.231V reference. The VFB pin is connected to a resistor divider from the converter output. Values for the resistor connected from VOUT to VFB (RFB1) and the resistor con- nected from VFB to ground (RFB2) can be calculated to pro- gram converter output voltage (V OUT) via the following relation: VOUT = 1.231 • (RFB1 + RFB2)/RFB2 The VFB pin input bias current is 35nA, so use of extremely high value feedback resistors could cause a converter output that is slightly higher than expected. Bias current error at the output can be estimated as: DV OUT(BIAS) = 35nA • RFB1 The voltage on V FB also controls the LT3433 oscillator frequency through a “frequency-foldback” function. When the VFB pin voltage is below 0.8V, the oscillator runs slower than the 200kHz typical operating frequency. The oscilla- tor frequency slows with reduced voltage on the pin, down to 50kHz when V FB = 0V. The VFB pin voltage also controls switch current limit through a “current-limit foldback” function. At VFB = 0V, the maximum switch current is reduced to half of the normal value. The current limit value increases linearly until VFB reaches 0.6V when the normal maximum switch current level is restored. The frequency and current-limit foldback functions add robustness to short-circuit protection and help prevent inductor current runaway during start-up. SS (Pin 10): Soft Start. Connect a capacitor (C SS) from this pin to ground. The output voltage of the LT3433 error amplifier corresponds to the peak current sense amplifier output detected before resetting the switch output(s). The soft-start circuit forces the error amplifier output to a zero peak current for start-up. A 5mA current is forced from the SS pin onto an external capacitor. As the SS pin voltage ramps up, so does the LT3433 internally sensed peak cur- rent limit. This forces the converter output current to ramp from zero until normal output regulation is achieved. This function reduces output overshoot on converter start-up. SGND (Pins 1, 8, 9, 16): Low Noise Ground Reference. V BST (Pin 2): Boosted Switch Supply. This “boosted” sup- ply rail is referenced to the SW_H pin. Supply voltage is maintained by a bootstrap capacitor tied from the V BST pin to the SW_H pin. A 1mF capacitor is generally adequate for most applications. The charge on the bootstrap capacitor is refreshed through a diode, typically connected from the converter output (VOUT), during the switch-off period. Minimum off-time operation assures that the boost capacitor is refreshed each switch cycle. The LT3433 supports operational VBST sup- ply voltages up to 75V (absolute maximum) as referenced to ground. SW_H (Pin 3): Boosted Switch Output. This is the current return for the boosted switch and corresponds to the emitter of the switch transistor. The boosted switch shorts the SW_H pin to the V IN supply when enabled. The drive cir- cuitry for this switch is boosted above the V IN supply through the VBST pin, allowing saturation of the switch for maximum efficiency. The “ON” resistance of the boosted switch is 0.8W . VIN (Pin 4): Input Power Supply. This pin supplies power to the boosted switch and corresponds to the collector of the switch transistor.This pin also supplies power to most of the IC’s internal circuitry if the V BIAS pin is not driven externally. This supply will be subject to high switching transient currents so this pin requires a high quality bypass capacitor that meets whatever application-specific input ripple current requirements exist. See Applications Infor- mation. BURST_EN (Pin 5): Burst Mode Enable Pin. Shorting this pin to SGND enables Burst Mode operation. If Burst Mode operation is not desired, connecting this pin to V BIAS or VOUT will disable the burst function. VC (Pin 6): Error Amplifier Output. The voltage on the VC pin corresponds to the maximum switch current per oscil- lator cycle. The error amplifier is typically configured as an integrator circuit by connecting an RC network from this pin to ground. This circuit typically creates the dominant pole for the converter regulation feedback loop. Specific in- tegrator characteristics can be configured to optimize tran- sient response. See Applications Information.

The time from VSS = 0V to maximum available current can be calculated given a capacitor CSS as: tSS = (2.7 • 105)CSS or 0.27s/mF SHDN (Pin 11): Shutdown. If the SHDN pin is externally pulled below 0.5V, low current shutdown mode is initiated. During shutdown mode, all internal functions are disabled, and I CC is reduced to 10mA. This pin is intended to receive a digital input, however, there is a small amount of input hysteresis built into the SHDN circuit to help assure glitch- free mode switching. If shutdown is not desired, connect the SHDN pin to V IN. VBIAS (Pin 12): Internal Local Supply. Much of the LT3433 circuitry is powered from this supply, which is internally regulated to 2.5V through an on-board linear regulator. Current drive for this regulator is sourced from the VIN pin. The VBIAS supply is short-circuit protected to 5mA. The VBIAS supply only sources current, so forcing this pin above the regulated voltage allows the use of external power for much of the LT3433 circuitry. When using external drive, this pin should be driven above 3V to assure the internal supply is completely disabled. This pin is typically diode- connected to the converter output to maximize conversion efficiency. This pin must be bypassed with at least a 0.1mF ceramic capacitor to SGND. V OUT (Pin 13): Converter Output Pin. This pin voltage is compared with the voltage on V IN internally to control operation in single or 2-switch mode. When the ratios of the two voltages are such that a >75% duty cycle is required for regulation, the low side switch is enabled. Drive bias for the low side switch is also derived directly from this pin. PWRGND (Pin 14): High Current Ground Reference. This is the current return for the low side switch and corresponds to the emitter of the low side switch transistor. SW_L (Pin 15): Ground Referenced Switch Output. This pin is the collector of the low side switch transistor. The low side switch shorts the SW_L pin to PWRGND when enabled. The series impedance of the ground-referenced switch is 0.6W .

SW_L VBST VIN BURST_EN VBIAS SW_H VFB GND VC OSCILLATOR 200kHz BOOSTED DRIVER COMPARATOR DRIVER 1.231V SHUTDOWN 5µA 0.7V 3433 BD 15% LOAD ERROR AMPLIFIER30% LOAD Burst Mode CONTROL SHDN SGND VOUT VOUT 1, 8, 9,16 SS MODE CONTROL SENSE AMPLIFIER 1.25V

APPLICATIO S I FOR ATIOWU UU Overview The LT3433 is a high input voltage range, step-up/step- down DC/DC converter IC using a 200kHz constant fre- quency, current mode architecture. Dual internal switches allow the full input voltage to be imposed across the switched inductor, such that both step-up and step-down modes of operation can be realized using the same single inductor topology. The LT3433 has provisions for high efficiency, low load operation for battery-powered applications. Burst Mode operation reduces average quiescent current to 100mA in no load conditions. A low current shutdown mode can also be activated, reducing total quiescent current to 10mA. Much of the LT3433’s internal circuitry is biased from an internal low voltage linear regulator. The output of this regulator is brought out to the V BIAS pin, allowing bypass- ing of the internal regulator. The associated internal circuitry can be powered directly from the output of the converter, increasing overall converter efficiency. Using externally derived power also eliminates the IC’s power dissipation associated with the internal V IN to V BIAS regulator. Theory of Operation (See Block Diagram) The LT3433 senses converter output voltage via the V FB pin. The difference between the voltage on this pin and an internal 1.231V reference is amplified to generate an error voltage on the VC pin which is, in turn, used as a threshold for the current sense comparator. During normal operation, the LT3433 internal oscillator runs at 200kHz. At the beginning of each oscillator cycle, the switch drive is enabled. The switch drive stays enabled until the sensed switch current exceeds the V C-derived threshold for the current sense comparator and, in turn, disables the switch driver. If the current comparator threshold is not obtained for the entire oscillator cycle, the switch driver is disabled at the end of the cycle for 250ns. This minimum off-time mode of operation assures regen- eration of the V BST bootstrapped supply. If the converter input and output voltages are close together, proper operation in normal buck configuration would require high duty cycles. The LT3433 senses this condition as requiring a duty cycle greater than 75%. If such a condition exists, a second switch is enabled during the switch on time, which acts to pull the output side of the inductor to ground. This “bridged” operation allows volt- age conversion to continue when V OUT approaches or exceeds VIN. Shutdown The LT3433 incorporates a low current shutdown mode where all IC functions are disabled and the VIN current is reduced to 10mA. Pulling the SHDN pin down to 0.4V or less activates shutdown mode. Burst Mode Operation The LT3433 employs low current Burst Mode functionality to maximize efficiency during no load and low load condi- tions. Burst Mode function is disabled by shorting the BURST_EN pin to either V BIAS or V OUT. Burst Mode function is enabled by shorting BURST_EN to SGND. When the required switch current, sensed via the VC pin voltage, is below 30% of maximum, the Burst Mode function is employed. When the voltage on VC drops below the 30% load level, that level of sense current is latched into the IC. If the output load requires less than this latched current level, the converter will overdrive the output slightly during each switch cycle. This overdrive condition forces the voltage on the V C pin to continue to drop. When the voltage on VC drops below the 15% load level, switching is disabled, and the LT3433 shuts down most of its internal circuitry, reducing quiescent current to 100mA. When the voltage on the V C pin climbs back to 20% load level, the IC returns to normal operation and switching resumes. Antislope Compensation Most current mode switching controllers use slope com- pensation to prevent current mode instability. The LT3433 is no exception. A slope compensation circuit imposes an artificial ramp on the sensed current to increase the rising slope as duty cycle increases. Unfortunately, this addi- tional ramp corrupts the sensed current value, reducing the achievable current limit value by the same amount as the added ramp represents. As such, current limit is typically reduced as duty cycles increase.

The LT3433 contains circuitry to eliminate the current limit reduction associated with slope-compensation, or anti- slope compensation. As the slope compensation ramp is added to the sensed current, a similar ramp is added to the current limit threshold reference. The end result is that current limit is not compromised so the LT3433 can provide full power regardless of required duty cycle. Mode Switching The LT3433 senses operational duty cycle by directly monitoring V IN and VOUT. Voltage drops associated with pass and catch diodes are estimated internally such that mode switching occurs when the duty cycle required for continuous buck operation is greater than 75%. If such a condition exists, a second switch is enabled during the switch on time, changing operation to a dual switch bridged configuration. Because the voltage available across the switched inductor is greater in bridged mode, duty cycle will decrease. The output current in bridged mode is not continuous, so switch currents are considerably higher than while oper- ating in buck mode. In order to maximize available output power, continuous operation and low ripple currents are recommended. Switch currents will increase by a factor of 1/(1 – DC) during bridged mode, so this mode of operation is typically the gating item for converter drive capability. I OUT(MAX) = ISW(MAX) • (1 –␣ DC) where DIL is the ripple current in the inductor. It is also important to note that IOUT cannot be considered equivalent to ILOAD during bridged operation. Most of the converter’s switch drive power is derived from the gener- ated output supply, so IOUT must also accommodate this current requirement. During single-switch buck opera- tional conditions, switch drive current is negligible in terms of output current; however, during bridged opera- tion, these currents can become significant. These output derived switch drive currents will increase the current loading on V IN by the same 1/(1 – DC) factor as the switch currents. As maximum switch current is referenced to that coming from the V IN supply, the available maximum switch current will be reduced by this required drive current. IDRIVE = DC • 2 • ISW(MAX) • ISWDRIVE(MAX) Using 50mA/A for the required drive current for each switch yields the portion of switch current used to drive the switches is: ISW(DRIVE) = DC • 2 • ISW(MAX) • 0.05/(1 – DC) Removing drive currents from the available maximum switch current yields: ISW(MAX)'=I SW(MAX) • [1 – DC • 2 • ISW(MAX) • 0.05/(1 – DC)] where ISW(MAX)' is maximum switch current available to the load during bridged operation. The maximum load current can then be calculated as: ILOAD(MAX) = ISW(MAX)' • (1 – DC) which reduces to: ILOAD(MAX) = [0.5A – (DIL/2)] • (1 – 1.1 • DC) Design Equations APPLICATIO S I FOR ATIOWU UU SW_H LT3433 VIN VOUT

3433 AI01

SW_L L Constants: VSWH = voltage drop across boosted switch VSWL = voltage drop across grounded switch VF = forward drop of external Schottky diodes f0 = operating frequency Duty Cycle (continuous operation): DCBUCK = (VOUT + 2VF)/(VIN – VSWH + VF) DCBRIDGED = (VOUT + 2VF)/(VOUT + VIN + 2VF – VSWH – VSWL)

Ripple current: D= +() -() -I VVD C LfLP P OUT F O Inductor Selection The primary criterion for inductor value selection in LT3433 applications is the ripple current created in that inductor. Design considerations for ripple current are the amount of output ripple and the ability of the internal slope compen- sation waveform to prevent current mode instability. The LT3433 maximizes available dynamic range using a slope compensation generator that generates a continu- ously increasing slope as duty cycle increases. The slope compensation waveform is calibrated at 80% duty cycle to compensate for ripple currents up to 12.5% of I MAX, or ~ 60mA. Ripple current can be calculated as: D= +() -() -I VVD C LfLP P OUT F O This relation can be used to determine minimum induc- tance sizes for various values of VOUT using the DC = 80% calibration: LMIN = (VOUT + 1.5V) • (1 – 0.8) 60mA • 200kHz) VOUT LMIN 4V 92 mH 5V 108 mH 9V 175 mH 12V 225 mH APPLICATIO S I FOR ATIOWU UU Discontinuous operation occurs when the ripple current in the inductor is greater than twice the load current (ILOAD) in buck mode, or greater than I LOAD/(1 – DC) during bridged mode. Current mode instability is not a concern during discontinuous operation so inductor values smaller than LMIN can be used. If such a small inductor is used, however, it must be assured that the converter never enters continuous operation at duty cycles greater than 50% to prevent current mode instability. Design Example VIN(MIN) = 4V, VOUT = 5V, L = 150mH Using VF = 0.75V yields: DC = (V OUT + 2VF)/(VOUT + VIN + 2VF – VSWH – VSWL) = 0.69 DI L = (VOUT + 2VF) • (1 – DC) • (L •␣ f0)–1 = 67mA ILOAD(MAX) = ISW(MAX) • (1 – 1.1 • DC)

Burst Only Low Noise 5V Maintenance Supply VBST SW_H VIN BURST_EN V C VFB SW_L PWRGND VOUT VBIAS SHDN SS SGND LT3433 1N4148 0.1µF C6 100pF 510k 2.2M V IN 4V TO 60V

3433 TA03

0.1µF 10µF 1N4148 33µH DS2 B160A 2.2µF VOUT 10mA 2.2µF DS1 B160A LT1761-5 GND OUTIN BYPSHDN 0.01µF UPACKAGE DESCRIPTIO 16-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1663) Exposed Pad Variation BB TYPICAL APPLICATIO U FE16 (BB) TSSOP 0203 0.09 – 0.20 (.0036 – .0079) 0° – 8° 0.45 – 0.75 (.018 – .030) 4.30 – 4.50* (.169 – .177) 6.40 BSC 13 4 5 6 7 8 10 9 4.90 – 5.10* (.193 – .201) 16 1514 13 12 11 1.10 (.0433) MAX 0.05 – 0.15 (.002 – .006) 0.65 (.0256) BSC 2.94 (.116) 0.195 – 0.30 (.0077 – .0118) 2RECOMMENDED SOLDER PAD LAYOUT 0.45 –0.05

0.65 BSC

4.50 –0.10 6.60 –0.10 1.05 –0.10 2.94 (.116) 3.58 (.141) 3.58 (.141) MILLIMETERS (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. DIMENSIONS ARE IN 3. DRAWING NOT TO SCALE SEE NOTE 4 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT

Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com ª LINEAR TECHNOLOGY CORPORA TION 2003 LT/TP 0903 1K REV A • PRINTED IN USA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1076/LT1076HV 1.6A (I OUT), 100kHz High Efficiency Step-Down DC/DC Converters V IN: 7.3V to 45V/64V, VOUT(MIN): 2.21V, IQ: 8.5mA, ISD: 10mA, DD5/DD7, TO220-5/TO220-7 LT1676 60V, 440mA (I OUT), 100kHz High Efficiency Step-Down V IN: 7.4V to 60V, VOUT(MIN): 1.24V, IQ: 3.2mA, DC/DC Converter I SD: 2.5mA, SO-8 LT1765 25V, 2.75A (I OUT), 1.25MHz High Efficiency Step-Down V IN: 3V to 25V, VOUT(MIN): 1.20V, IQ: 1mA, DC/DC Converter I SD: 15mA, SO-8, TSSOP16E LT1766/LT1956 60V, 1.2A (I OUT), 200kHz/500kHz High Efficiency Step-Down V IN: 5.5V to 60V, VOUT(MIN): 1.20V, IQ: 2.5mA, DC/DC Converters I SD: 25mA, TSSOP16/TSSOP16E LT1767 25V, 1.2A (I OUT), 1.25MHz High Efficiency Step-Down V IN: 3V to 25V, VOUT(MIN): 1.20V, IQ: 1mA, DC/DC Converter I SD: 6mA, MS8/MS8E LT1776 40V, 550mA (I OUT), 200kHz High Efficiency Step-Down V IN: 7.4V to 40V, VOUT(MIN): 1.24V, IQ: 3.2mA, DC/DC Converter I SD: 30mA, N8, SO-8 LT1976 60V, 1.2A (I OUT), 200kHz High Efficiency Micropower (IQ < 100mA) V IN: 3.3V to 60V, VOUT(MIN): 1.20V, IQ: 100mA, Step-Down DC/DC Converter I SD: <1mA, TSSOP16E LT3010 80V, 50mA Low Noise Linear Regulator V IN: 1.5V to 80V, VOUT(MIN): 1.28V, IQ: 30mA, ISD: <1mA, MS8E LTC3412/LTC3414 2.5A (I OUT), 4MHz Synchronous Step-Down DC/DC Converters V IN: 2.5V to 5.5V, VOUT(MIN): 0.8V, IQ: 60mA, ISD: <1mA, TSSOP16E LTC3414 4A (I OUT), 4MHz Synchronous Step-Down DC/DC Converter V IN: 2.3V to 5.5V, VOUT(MIN): 0.8V, IQ: 64mA, ISD: <1mA, TSSOP20E LTC3727/LTC3727-1 36V, 500kHz High Efficiency Step-Down DC/DC Controllers V IN: 4V to 36V, VOUT(MIN): 0.8V, IQ: 670mA, ISD: 20mA, QFN32, SSOP28 LT3430/LT3431 60V, 2.75A (I OUT), 200kHz/500kHz High Efficiency Step-Down V IN: 5.5V to 60V, VOUT(MIN): 1.20V, IQ: 2.5mA, DC/DC Converters I SD: 30mA, TSSOP16E LTC3440 600mA (I OUT), 2MHz Synchronous Buck-Boost DC/DC Converter V IN: 2.5V to 5.5V, VOUT(MIN): 2.5V, IQ: 25mA, with 95% Efficiency I SD: <1mA, MS10 4V-60V to 5V at 100mA DC/DC Converter Burst Disabled VBST SW_H VIN BURST_EN V C VFB SW_L PWRGND VOUT VBIAS SHDN SS SGND LT3433 1N4148 0.1µF R1 68k 305k 0.5% 100k 0.5% C5 1nF C4 100pF VIN 4V TO 60V 0.01µF

3433 TA02

0.1µF 1N4148 100µH DS2 B160A 47µF VOUT 100mA 2.2µF DS1 B160A TYPICAL APPLICATIO U