DATASHEET SEARCH SITE | WWW.ALLDATASHEET.COM
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 20
Technical content
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd TYPICAL APPLICATION
DESCRIPTION
Monolithic 3A, 1.25MHz Step-Down Switching Regulator The L T®1765 is a 1.25MHz monolithic buck switching regulator . A high effi ciency 3A, 0.09Ω switch is included on the die together with all the control circuitry required to construct a high frequency, current mode switching regulator . Current mode control provides fast transient response and excellent loop stability. New design techniques achieve high effi ciency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains con- sistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA improves effi ciency, especially at lower output currents. Shutdown reduces quiescent current to 15μA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator into the range of 1.6MHz to 2MHz. Full cycle-by-cycle current control and thermal shutdown are provided. High frequency operation allows the reduc- tion of input and output fi ltering components and permits the use of chip inductors. L, L T , L TC and L TM are registered trademarks of Linear Technology Corporation. *Patent Pending 5V to 3.3V Step-Down Converter
FEATURES
APPLICATIONS
n 3A Switch in a Thermally Enhanced 16-Lead TSSOP or 8-Lead SO Package n Constant 1.25MHz Switching Frequency n Wide Operating Voltage Range: 3V to 25V n High Effi ciency 0.09Ω Switch n 1.2V Feedback Reference Voltage n Uses Low Profi le Surface Mount Components n Low Shutdown Current: 15μA n Synchronizable to 2MHz n Current Mode Loop Control n Constant Maximum Switch Current Rating at All Duty Cycles* n Available in 8-Lead SO and 16-Lead Thermally Enhanced TSSOP Packages BOOST LT1765-3.3 VIN OUTPUT 3.3V 2.5A INPUT
1765 TA01
0.18μF 2.2nF UPS120 4.7μF CERAMIC 2.2μF CERAMIC CMDSH-3 1.5μH VSW FBSHDN ONOFF GND VCSYNC Effi ciency vs Load Current SWITCH CURRENT (A) EFFICIENCY (%) 2.0 1765 • TAO1a 0.5 1.0 1.5 VIN = 10V VOUT = 5V
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd ABSOLUTE MAXIMUM RATINGS (Note 1) FE PACKAGE 16-LEAD PLASTIC TSSOP TOP VIEW GND BOOST V IN VIN SW SW NC GND GND NC SYNC V C FB SHDN NC GND θJA = 45°C/W , θJC(PAD) = 10°C/W EXPOSED PAD (PIN 17) SOLDERED TO LARGE COPPER PLANE TOP VIEW SYNC VC FB SHDN BOOST V IN SW GND S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 125°C, θJA = 90°C/W , θJC(PIN 4) = 30°C/W GROUND PIN CONNECTED TO LARGE COPPER AREA PIN CONFIGURATION ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1765EFE#PBF L T1765EFE#TRPBF 1765EFE 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-1.8#PBF L T1765EFE-1.8#TRPBF 1765EFE-1.8 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-2.5#PBF L T1765EFE-2.5#TRPBF 1765EFE-2.5 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-3.3#PBF L T1765EFE-3.3#TRPBF 1765EFE-3.3 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-5#PBF L T1765EFE-5#TRPBF 1765EFE-5 16-Lead Plastic TSSOP –40°C to 125°C L T1765ES8#PBF L T1765ES8#TRPBF 1765 8-Lead Plastic SO –40°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1765EFE L T1765EFE#TR 1765EFE 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-1.8 L T1765EFE-1.8#TR 1765EFE-1.8 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-2.5 L T1765EFE-2.5#TR 1765EFE-2.5 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-3.3 L T1765EFE-3.3#TR 1765EFE-3.3 16-Lead Plastic TSSOP –40°C to 125°C L T1765EFE-5 L T1765EFE-5#TR 1765EFE-5 16-Lead Plastic TSSOP –40°C to 125°C L T1765ES8 L T1765ES8#TR 1765 8-Lead Plastic SO –40°C to 125°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/ Operating Junction Temperature Range
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd
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 T1765E is guaranteed to meet performance specifi cations from 0°C to 125°C. Specifi cations over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. PARAMETER CONDITIONS MIN TYP MAX UNITS Maximum Switch Current Limit 346 A Oscillator Frequency 3.3V < V IN < 25V l 1.1 1.25 1.6 MHz Switch On Voltage Drop I = 3A l 270 430 mV VIN Undervoltage Lockout (Note 3) l 2.47 2.6 2.73 V VIN Supply Current l 1 1.3 mA Shutdown Supply Current V SHDN = 0V, VIN = 25V, VSW = 0V l 15 35 μA μA Feedback Voltage 3V < V IN < 25V, 0.4V < VC < 0.9V (Note 3) L T1765 (Adj) l 1.182 1.176 1.2 1.218 1.224 V V L T1765-1.8 l 1.764 1.8 1.836 V L T1765-2.5 l 2.45 2.5 2.55 V L T1765-3.3 l 3.234 3.3 3.366 V L T1765-5 l 4.9 5 5.1 V FB Input Current L T1765 (Adj) l –0.25 –0.5 μA FB Input Resistance L T1765-1.8 L T1765-2.5 L T1765-3.3 L T1765-5 l l l l 10.5 14.7 27.5 kΩ kΩ kΩ kΩ FB Error Amp Voltage Gain 0.4V < V C < 0.9V 150 350 FB Error Amp T ransconductance ΔIVC = ±10μA l 500 850 1300 μMho VC Pin Source Current V FB = VNOM – 17% l 80 120 160 μA VC Pin Sink Current V FB = VNOM + 17% l 70 110 180 μA VC Pin to Switch Current T ransconductance 5A / V VC Pin Minimum Switching Threshold Duty Cycle = 0% 0.4 V VC Pin 3A ISW Threshold 0.9 V Maximum Switch Duty Cycle V C = 1.2V, ISW = 800mA, VIN = 6V l 90 % Minimum Boost Voltage Above Switch I SW = 3A l 1.8 2.7 V Boost Current I SW = 1A (Note 4) ISW = 3A (Note 4) l l 140 mA mA SHDN Threshold Voltage l 1.27 1.33 1.40 V SHDN Threshold Current Hysteresis l 47 1 0 μ A SHDN Input Current (Shutting Down) SHDN = 60mV Above Threshold l –7 –10 –13 μA SYNC Threshold Voltage 1.5 2.2 V SYNC Input Frequency 1.6 2 MHz SYNC Pin Resistance I SYNC = 1mA 20 kΩ The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 15V, VC = 0.8V, Boost = VIN + 5V, SHDN, SYNC and switch open unless otherwise noted. Note 3: Minimum input voltage is defi ned as the voltage where the internal regulator enters lockout. Actual minimum input voltage to maintain a regulated output will depend on output voltage and load current. See Applications Information. Note 4: Current fl ows into the BOOST pin only during the on period of the switch cycle.
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd TYPICAL PERFORMANCE CHARACTERISTICS TEMPERATURE (°C) –50 FB VOLTAGE (V) 100
1765 G01
1.220 1.215 1.210 1.205 1.200 1.195 1.190 1.185 1.180 –25 25 75 125 SWITCH CURRENT (A) 350 300 250 200 150 100
1765 G02
SWITCH VOLTAGE (mV) TA = 125°C TA = –40°C TA = 25°C TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 FREQUENCY (MHz)
1765 G03
1.50 1.45 1.40 1.35 1.30 1.25 1.20 1.15 1.10 TEMPERATURE (°C) –50 –25 0 25 50 75 100 125 SHDN THRESHOLD (V)
1765 G04
1.40 1.38 1.36 1.34 1.32 1.30 VIN (V) 0 5 10 15 20 25 30 VIN CURRENT (μA)
1765 G05
SHDN = 0V VIN (V) 0 5 10 15 20 25 30 VIN CURRENT (μA) SHDN = 0V SHDN Threshold vs Temperature SHDN Supply Current vs VIN SHDN IP Current vs Temperature FB vs Temperature (Adj) Switch On Voltage Drop Oscillator Frequency
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd TYPICAL PERFORMANCE CHARACTERISTICS LOAD CURRENT (A) 0.001 0.01 0.1 1 INPUT VOLTAGE (V)
1765 G07
3.5 3.3 3.1 2.9 2.7 2.5 SHUTDOWN VOLTAGE (V) VIN CURRENT (μA)
1765 G08
VIN = 15V INPUT VOLTAGE (V) 0 5 10 15 20 25 30 VIN CURRENT (μA)
1765 G09
FEEDBACK VOLTAGE (V) SWITCH PEAK CURRENT (A)
1765 G10
FB INPUT CURRENT (μA) FB CURRENT SWITCH CURRENT
1765 G11
INPUT VOLTAGE (V) 0 5 10 15 20 25 OUTPUT CURRENT (A) 3.0 2.8 2.6 2.4 2.2 2.0 L = 4.7μH L = 2.2μH L = 1.5μH INPUT VOLTAGE (V) 05 10 15 20 25 OUTPUT CURRENT (A)
1765 G12
3.0 2.8 2.6 2.4 2.2 L = 4.7μH L = 2.2μH L = 1.5μH Current Limit Foldback Maximum Load Current, VOUT = 5V Maximum Load Current, VOUT = 2.5V Minimum Input Voltage for 2.5V Out SHDN Supply Current Input Supply Current
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd PIN FUNCTIONS FB: The feedback pin is used to set output voltage using an external voltage divider (adjustable version) that gener- ates 1.2V at the pin when connected to the desired output voltage. The fi xed voltage 1.8V , 2.5V, 3.3V and 5V versions have the divider network included internally and the FB pin is connected directly to the output. If required, the current limit can be reduced during start up or short-circuit when the FB pin is below 0.5V (see the Current Limit Foldback graph in the Typical Performance Characteristics section). An impedance of less than 5kΩ on the adjustable version at the FB pin is needed for this feature to operate. BOOST : The BOOST pin is used to provide a drive voltage, higher than the input voltage, to the internal bipolar NPN power switch. V IN: This is the collector of the on-chip power NPN switch. This pin powers the internal circuitry and internal regulator . At NPN switch on and off, high di/dt edges occur on this pin. Keep the external bypass capacitor and catch diode close to this pin. All trace inductance on this path will create a voltage spike at switch off, adding to the V CE volt- age across the internal NPN. Both VIN pins of the TSSOP package must be shorted together on the PC board. GND: The GND pin acts as the reference for the regulated output, so load regulation will suffer if the “ground” end of the load is not at the same voltage as the GND pin of the IC. This condition will occur when load current or other currents fl ow through metal paths between the GND pin and the load ground point. Keep the ground path short between the GND pin and the load and use a ground plane when possible. Keep the path between the input bypass and the GND pin short. The exposed GND pad and/or GND pins of the package are directly attached to the internal tab. These pins/pad should be attached to a large copper area to reduce thermal resistance. V SW: The switch pin is the emitter of the on-chip power NPN switch. This pin is driven up to the input pin voltage during switch on time. Inductor current drives the switch pin negative during switch off time. Negative voltage must be clamped with an external catch diode with a V BR <0.8V. Both VSW pins of the TSSOP package must be shorted together on the PC board. SYNC: The sync pin is used to synchronize the internal oscillator to an external signal. It is directly logic compat- ible and can be driven with any signal between 20% and 80% duty cycle. The synchronizing range is from 1.6MHz to 2MHz. See Synchronization section in Applications Information for details. When not in use, this pin should be grounded. SHDN: The shutdown pin is used to turn off the regula- tor and to reduce input drain current to a few microam- peres. The 1.33V threshold can function as an accurate undervoltage lockout (UVLO), preventing the regulator from operating until the input voltage has reached a pre- determined level. Float or pull high to put the regulator in the operating mode. V C: The VC pin is the output of the error amplifi er and the input of the peak switch current comparator . It is normally used for frequency compensation, but can do double duty as a current clamp or control loop override. This pin sits at about 0.4V for very light loads and 0.9V at maximum load. It can be driven to ground to shut off the output.
1765 F01
of the error amplifi er to set the switch current trip point. current to be delivered to the output rather than voltage. much quicker transient response. than the input voltage, allowing the switch to be saturated. disables the internal regulator , reducing supply current. Figure 1. Block Diagram
Figure 2. Feedback Network
1765 F02
should be used and an external resistor divider added. The suggested resistor (R2) from FB to ground is 10k. voltage by 2:1 for high surge applications. series R to compensate for this. current into a tight local loop, thereby minimizing EMI.
Table 2. Surface Mount Solid Tantalum Capacitor ESR and tantalum capacitor at 200mA ripple current. resulting in excessive power dissipation. Figure 3. Output Ripple Voltage Waveform
1765 F03
tains a constant switch current rating at all duty cycles. output currents due to reduced peak to peak ripple current.
operation under these conditions must be tolerated. throughout the on period to keep the switch fully saturated. it is recommended that an alternate boost supply is used. supply can be used with a local bypass capacitor . discharge ripple and improve start up operation. where these problems might occur . Figure 4. Undervoltage Lockout
1765 F04
4.75V and is to stop if the input falls below 3.75V . more details on the theory of slope compensation. Figure 5. High Speed Switching Path
1765 F05
or subharmonic like oscillation. thermal resistance to a minimum. be used for calculating effi ciency at light load currents. Figure 6. Typical Application and Layout (Topside Only Shown)
1765 F06
1765 F6a
diode will also be dissipating power . lower VF diode can improve effi ciency by several percent. 40k with a temperature coeffi cient of 0.16%/°C is typical. indicate the die temperature. circuits, read the ‘LAYOUT CONSIDERATIONS’ section fi rst. of the phase shift problems associated with the inductor . amplifi er and the power stage. Figure 7. Model for Loop Response
1765 F07
capacitor and a typical 100μF tantalum output capacitor . dominant. A typical value of 2.2nF will achieve this. C may stop loop gain rolling off altogether . voltage monitored for a well-damped behavior . regulation, Q1 turns off and the circuit operates normally. R3 is transient protection for the base of Q1. Figure 8. Overall Loop Response
1765 F08
Figure 10. Buck Converter with Adjustable Soft Start
1765 F10
be used for sequencing multiple regulator outputs. changes L1B current waveform from square to triangular . Figure 9. Dual Source Supply with 6μA Reverse Leakage
1765 F09
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd APPLICATIONS INFORMATION Figure 11a. Dual Output Converter OUTPUT 5V AT 1.5A OUTPUT –5V† AT 1.1A * L1 IS A SINGLE CORE WITH TWO WINDINGS COILTRONICS CTX5-1A † IF LOAD CAN GO TO ZERO, AN OPTIONAL PRELOAD OF 1k TO 5k MAY BE USED TO IMPROVE LOAD REGULATION D1, D3: B220A INPUT 12V GND
1765 F11a
0.18μF CC 4700pF RC 3.3k D1 4.7μF 6.3V CERAMIC 4.7mF 6.3V CERAMIC 2.2μF 25V CERAMIC 4.7μF 16V CERAMIC CMDSH-3 L1A* L1B* BOOST LT1765-5 VIN VSW FBSHDN GND VCSYNC Figure 11b. Dual Output Converter (Output Currents) 5V LOAD CURRENT (mA) 10 100 1000 10000 MAX –5V LOAD (mA)
1765 F11b
Figure 12. Positive-to-Negative Low Output Ripple Converter
1765 F12
Figure 13. Negative Boost Converter
1765 F13
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd PACKAGE DESCRIPTION 16-Lead Plastic TSSOP (4.4mm) (Reference L TC DWG # 05-08-1663) Exposed Pad Variation BB FE16 (BB) TSSOP 0204 0.09 – 0.20 (.0035 – .0079) 0° – 8° 0.25 REF 0.50 – 0.75 (.020 – .030) 4.30 – 4.50* (.169 – .177) 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) TYP 2RECOMMENDED SOLDER PAD LAYOUT 0.45 p0.05
0.65 BSC
4.50 p0.10 6.60 p0.10 1.05 p0.10 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 6.40 (.252) BSC
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd 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 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference L TC DWG # 05-08-1610) .016 – .050 (0.406 – 1.270) .010 – .020 0°– 8° TYP .008 – .010 (0.203 – 0.254) SO8 0303 .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.483) TYP .004 – .010 (0.101 – 0.254) .050 (1.270) BSC 1 2 3 4 .150 – .157 (3.810 – 3.988) NOTE 3 8 7 6 5 .189 – .197 (4.801 – 5.004) NOTE 3 .228 – .244 (5.791 – 6.197) .245 MIN .160 p.005 RECOMMENDED SOLDER PAD LAYOUT .045 p.005 .050 BSC .030 p.005 TYP INCHES (MILLIMETERS) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 1765fd Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com © LINEAR TECHNOLOGY CORPORATION 2001 LT 0608 REV D • PRINTED IN USA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS L T1074/L T1074HV 4.4A (I OUT), 100kHz, High Effi ciency Step-Down DC/DC Converter V IN: 7.3V to 45V/64V, VOUT(MIN) = 2.21V, IQ = 8.5mA, ISD = 10μA, DD5/7, TO220-5/7 L T1076/L T1076HV 1.6A (I OUT), 100kHz, High Effi ciency Step-Down DC/DC Converter V IN: 7.3V to 45V/64V, VOUT(MIN) = 2.21V, IQ = 8.5mA, ISD = 10μA, DD5/7, TO220-5/7 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, SO-8 L T1765 25V , 2.75A (I OUT), 1.25MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V , VOUT(MIN) = 1.20V , IQ = 1mA, ISD < 15μA, SO-8, TSSOP16E L T1766 60V , 1.2A (IOUT), 200kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN) = 1.20V, IQ = 2.5mA, ISD < 25μA, TSSOP16/E L T1767 25V , 1.2A (I OUT), 1.25MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V, VOUT(MIN) = 1.20V, IQ = 1mA, ISD < 6μA, MS8/E 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, N8, SO-8 L T1940 25V , Dual 1.2A (I OUT), 1.1MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V, VOUT(MIN) = 1.2V, IQ = 3.8mA, ISD = < 1μA, TSSOP16E L T1956 60V , 1.2A (I OUT), 500kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN) = 1.20V, IQ = 2.5mA, ISD < 25μA, TSSOP16/E L T1976 60V , 1.2A (I OUT), 200kHz, High Effi ciency Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.3V to 60V, VOUT(MIN) = 1.20V, IQ = 100μA, ISD < 1μA, TSSOP16E L T3010 80V , 50mA, Low Noise Linear Regulator V IN: 1.5V to 80V, VOUT(MIN) = 1.28V, IQ = 30μA, ISD < 1μA, MS8E L TC3407 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, MS10E L TC3412 2.5A (I OUT), 4MHz, Synchronous Step-Down DC/DC Converter V IN: 2.5V to 5.5V, VOUT(MIN) = 0.8V, IQ = 60μA, ISD < 1μA, TSSOP16E 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, TSSOP20E L T3430/L T3431 60V , 2.75A (I OUT), 200kHz/500kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN) = 1.20V, IQ = 2.5mA, ISD = 30μA, TSSOP16E L T3433 60V , 400mA (I OUT), 200kHz, High Effi ciency Step-Up/Step-Down DC/DC Converter with Burst Mode Operation VIN: 4V to 60V, VOUT(MIN) = 3.3V to 20V, IQ = 100μA, ISD < 1μA, TSSOP16E L TC3727/L TC3727-1 36V , 500kHz, High Effi ciency Step-Down DC/DC Converter V IN: 4V to 36V, VOUT(MIN) = 0.8V, IQ = 670μA, ISD < 20μA, QFN32, SSOP28 Burst Mode is a registered trademark of Linear Technology Corporation.