Datasheet LTC1625 (Analog Devices)

ManufacturerAnalog Devices
DescriptionNo RSENSE Current Mode Synchronous Step-Down Switching Regulator
Pages / Page24 / 1 — FEATURES. DESCRIPTION. Highest Efficiency Current Mode Controller. No …
File Format / SizePDF / 392 Kb
Document Languageenglish

FEATURES. DESCRIPTION. Highest Efficiency Current Mode Controller. No Sense Resistor Required. Stable High Current Operation

Datasheet LTC1625 Analog Devices

Model Line for this Datasheet

Text Version of Document

LTC1625 No R TM SENSE Current Mode Synchronous Step-Down Switching Regulator

Highest Efficiency Current Mode Controller
The LTC®1625 is a synchronous step-down switching ■
No Sense Resistor Required
regulator controller that drives external N-Channel power ■
Stable High Current Operation
MOSFETs using few external components. Current mode ■
Dual N-Channel MOSFET Synchronous Drive
control with MOSFET VDS sensing eliminates the need for ■ Wide VIN Range: 3.7V to 36V a sense resistor and improves efficiency. The frequency of ■ Wide VOUT Range: 1.19V to VIN a nominal 150kHz internal oscillator can be synchronized ■ ±1% 1.19V Reference to an external clock over a 1.5:1 frequency range. ■ Programmable Fixed Frequency with Injection Lock Burst ModeTM operation at low load currents reduces ■ Very Low Drop Out Operation: 99% Duty Cycle switching losses and low dropout operation extends oper- ■ Forced Continuous Mode Control Pin ating time in battery-powered systems. A forced continu- ■ Optional Programmable Soft Start ous mode control pin can assist secondary winding ■ Pin Selectable Output Voltage regulation by disabling Burst Mode operation when the ■ Foldback Current Limit main output is lightly loaded. ■ Output Overvoltage Protection ■ Logic Controlled Micropower Shutdown: I Fault protection is provided by foldback current limiting Q < 30µA ■ Available in 16-Lead Narrow SSOP and SO Packages and an output overvoltage comparator. An external ca- pacitor attached to the RUN/SS pin provides soft start
capability for supply sequencing. A wide supply range
allows operation from 3.7V (3.9V for LTC1625I) to 36V at the input and 1.19V to V ■ IN at the output. Notebook and Palmtop Computers, PDAs ■ Cellular Telephones and Wireless Modems , LTC and LT are registered trademarks of Linear Technology Corporation. No RSENSE and Burst Mode are trademarks of Linear Technology Corporation. ■ Battery Chargers ■ Distributed Power
U TYPICAL APPLICATION Efficiency vs Load Current
100 VIN VIN = 10V SYNC V V IN 5V TO OUT = 5V + CIN RUN/SS TK 28V 10µF CSS M1 90 0.1µF TG 30V Si4410DY L1 LTC1625 ×2 VOUT = 3.3V 10µH I SW V TH OUT CB 0.22µF 3.3V RC BOOST + COUT 4.5A 80 10k D D1 B 100µF CMDSH-3 MBRS140T3 CVCC 4.7µF 10V C EFFICIENCY (%) C V INTV PROG CC + ×3 2.2nF M2 70 SGND BG Si4410DY VOSENSE PGND 1625 F01 60 0.01 0.1 1 10 LOAD CURRENT (A)
Figure 1. High Efficiency Step-Down Converter
1625 TA01 1
PCB Design Analysis Software-NextDFM One-click Design Analysis for Manufacturability Layout Engineer Free Forever