Datasheet LT3462, LT3462A (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Inverting 1.2MHz/2.7MHz DC/DC Converters with Integrated Schottky |
| Pages / Page | 12 / 1 — FEATURES. DESCRIPTION. Integrated Schottky Rectifier. Fixed Frequency … |
| Revision | A |
| File Format / Size | PDF / 480 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Integrated Schottky Rectifier. Fixed Frequency 1.2MHz/2.7MHz Operation
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Text Version of Document
LT3462/LT3462A Inverting 1.2MHz/2.7MHz DC/DC Converters with Integrated Schottky
FEATURES DESCRIPTION
n
Integrated Schottky Rectifier
The LT®3462/LT3462A are general purpose fixed fre‑ n
Fixed Frequency 1.2MHz/2.7MHz Operation
quency current mode inverting DC/DC converters. Both n
Very Low Noise: 1mVP-P Output Ripple
devices feature an integrated Schottky and a low VCESAT n Low VCESAT Switch: 270mV at 250mA switch allowing a small converter footprint and lower n –5V at 100mA from 5V Input parts cost. The LT3462 switches at 1.2MHz while the n –12V at 30mA from 3.3V Input LT3462A switches at 2.7MHz. These high speeds enable n Low Input Bias Current GND Based FB Input the use of tiny, low cost and low height capacitors and n Low Impedance (40Ω) 1.265V Reference Output inductors. n High Output Voltage: Up to –38V The LT3462/LT3462A operate in a dual inductor inverting n Wide Input Range: 2.5V to 16V topology that filters both the input and output currents. n Uses Tiny Surface Mount Components Very low output voltage ripple approaching 1mVP‑P can n Low Shutdown Current: <10µA be achieved when ceramic capacitors are used. Fixed fre‑ n Low Profile (1mm) SOT‑23 (ThinSOT™) Package quency switching ensures a clean output free from low n 8‑Lead DFN (2mm × 2mm × 0.75mm) Package, frequency noise typically present with charge pump solu‑ LT3462A Only tions. The 40V switch allows a VIN to VOUT differential of up to 38V for dual inductor topologies.
APPLICATIONS
Both devices provide a low impedance 1.265V reference output to supply the feedback resistor network. A ground n CCD Bias referenced, high impedance FB input allows high feedback n LCD Bias resistor values without compromising output accuracy. n GaAs FET Bias n All registered trademarks and trademarks are the property of their respective owners. General Purpose Negative Voltage Supply
TYPICAL APPLICATION 5V to –5V, 100mA Inverting DC/DC Converter Efficiency
75 T 22µH 1µF 22µH A = 25°C VIN VIN = 5V 5V V 70 OUT –5V VIN = 3.3V 267k 100mA 22pF SW D V FB 65 1µF IN LT3462A 68.1k 10µF EFFICIENCY (%) SDREF 60 GND 3462 TA01 55 0 20 40 60 80 100 LOAD CURRENT (mA) 3462 TA01b Rev A Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Integrated Schottky Rectifier
The LT®3462/LT3462A are general purpose fixed fre‑ n
Fixed Frequency 1.2MHz/2.7MHz Operation
quency current mode inverting DC/DC converters. Both n
Very Low Noise: 1mVP-P Output Ripple
devices feature an integrated Schottky and a low VCESAT n Low VCESAT Switch: 270mV at 250mA switch allowing a small converter footprint and lower n –5V at 100mA from 5V Input parts cost. The LT3462 switches at 1.2MHz while the n –12V at 30mA from 3.3V Input LT3462A switches at 2.7MHz. These high speeds enable n Low Input Bias Current GND Based FB Input the use of tiny, low cost and low height capacitors and n Low Impedance (40Ω) 1.265V Reference Output inductors. n High Output Voltage: Up to –38V The LT3462/LT3462A operate in a dual inductor inverting n Wide Input Range: 2.5V to 16V topology that filters both the input and output currents. n Uses Tiny Surface Mount Components Very low output voltage ripple approaching 1mVP‑P can n Low Shutdown Current: <10µA be achieved when ceramic capacitors are used. Fixed fre‑ n Low Profile (1mm) SOT‑23 (ThinSOT™) Package quency switching ensures a clean output free from low n 8‑Lead DFN (2mm × 2mm × 0.75mm) Package, frequency noise typically present with charge pump solu‑ LT3462A Only tions. The 40V switch allows a VIN to VOUT differential of up to 38V for dual inductor topologies.
APPLICATIONS
Both devices provide a low impedance 1.265V reference output to supply the feedback resistor network. A ground n CCD Bias referenced, high impedance FB input allows high feedback n LCD Bias resistor values without compromising output accuracy. n GaAs FET Bias n All registered trademarks and trademarks are the property of their respective owners. General Purpose Negative Voltage Supply
TYPICAL APPLICATION 5V to –5V, 100mA Inverting DC/DC Converter Efficiency
75 T 22µH 1µF 22µH A = 25°C VIN VIN = 5V 5V V 70 OUT –5V VIN = 3.3V 267k 100mA 22pF SW D V FB 65 1µF IN LT3462A 68.1k 10µF EFFICIENCY (%) SDREF 60 GND 3462 TA01 55 0 20 40 60 80 100 LOAD CURRENT (mA) 3462 TA01b Rev A Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
