Datasheet LTC7149 (Analog Devices)

ManufacturerAnalog Devices
Description60V, 4A Synchronous Step-Down Regulator for Inverting Outputs
Pages / Page26 / 1 — Wide VIN Range: 3.4V to 60V. Wide VOUT Range: 0V to –28V. Single Resistor …
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Wide VIN Range: 3.4V to 60V. Wide VOUT Range: 0V to –28V. Single Resistor VOUT Programming

Datasheet LTC7149 Analog Devices

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LTC7149 60V, 4A Synchronous Step-Down Regulator for Inverting Outputs FEATURES DESCRIPTION n
Wide VIN Range: 3.4V to 60V
The LTC®7149 is a high efficiency 60V, 4A synchronous n
Wide VOUT Range: 0V to –28V
monolithic step-down regulator for inverting output n
Single Resistor VOUT Programming
applications. The regulator features a single resistor- n
Integrated 110mΩ Top N-Channel/50mΩ Bottom
programmable output voltage and high efficiency over a
N-Channel MOSFETs
wide VOUT range. n
Regulated IQ: 440µA, Shutdown IQ: 15µA
The inverting regulator operates from an input voltage n
Board GND Referenced I/O Pins (RUN, PGOOD,
range of 3.4V to 60V and provides an adjustable output
from (–28V) to zero volts while delivering up to 4A of n
Accurate Resistor Programmable
inductor current. The switching frequency is also set
Frequency (300kHz to 3MHz) with ±50%
with an external resistor. A user-selectable mode input is
Frequency Sync Range
provided to allow the user to trade off ripple noise for ef- n 92% Efficiency with 12 VIN and –5VOUT ficiency at light loads; Burst Mode operation provides the n ±0.8% Output Voltage Accuracy highest efficiency at light loads, while forced continuous n Peak Current Mode Operation mode provides low output ripple. The MODE/SYNC pin n Burst Mode® Operation, Forced Continuous Mode can also be used to synchronize the switching frequency n Programmable Soft-Start to an external clock. Internal level-shift circuits allow the n Overtemperature Protection I/O pins (RUN, MODE/SYNC, PGOOD) to be referenced n Available in 28-Lead (4mm x 5mm) QFN and to board GND. TSSOP Packages The LTC7149 operates with a peak current mode architec- APPLICATIONS ture that allows for fast transient response with inherent cycle-to-cycle current limit protection. n Industrial Applications n Telecom Power Supplies All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5847554, 6580258. n Distributed Power Systems TYPICAL APPLICATION
Efficiency with V Efficiency with V OUT = –5V OUT = –5V
0.1µF 100 6.8µH V 95 IN RUN BOOST SW 24V + VIN VOUTSNS 150μF 90 22µF 22µF × 2 0.1µF – V – GND LTC7149 V OUT OUT –5V 85 ITH 3.3A SV – OUT EFFICIENCY (%) INTV 80 CC 1k ISET MODE/SYNC RT 100pF 2.2µF 75 VIN = 12V 4.7nF 100k 10nF 200k VIN = 24V 70 7149 TA01 0 0.5 1 1.5 2 2.5 3 3.5 4 fSW = 500kHz IOUT (A) 7149 TA01b 7149fa For more information 1