AS7620_13 Datasheet, PDF (1/16 Pages) ams AG – 650mA, Ul t ra low Ripple Step Down DC/DC Conver ter

AS7620
650mA, Ultra low Ripple Step Down DC/DC Converter
1 General Description
The AS7620 is an easy-to-use, high-efficiency, high-voltage,
hysteretic step-down DC-DC converter, operating in asynchronous
mode. Its low-power architecture extends hold-up time in battery-
backed and critical applications where maximum up-time over a wide
input supply voltage range is needed, while still providing for high
efficiencies of up to 90% during peak current demands.
Although the AS7620 is optimized for 24V applications found in
industrial and medical systems, its ability to support 100% Duty
Cycle makes the AS7620 ideal for applications demanding maximum
up-time and soft power fail behavior. In combination with low idle
current of only 30µA, on-demand switching reduces operating
current at low load currents.
By selecting an appropriate inductor value, operating current can be
lowered and switching frequencies tuned to certain load conditions.
A pin-strapped current limit input minimizes inductor peak current
and thus inductor size and cost for any given application.
The device further includes output short-circuit protection and
thermal shutdown. In shutdown mode, only 1µA (typ) of current is
consumed.
Figure 1. AS7620 - Block Diagram
2 Key Features
Low quiescent current for efficient partial load operation
Wide Supply Voltage Range, 3.6V to 32V
100% Duty Cycle extends operating range
Pin-programmable cycle-by-cycle current limit
Integrated PMOS eliminates bootstrap capacitor
Resistor-programmable Early Power Fail Warning Input
Power-Good Flag
Thermal Shutdown
Fixed 3.3V and adjustable output (1.2V to VIN)
Small 4x4mm 12-Lead MLPQ Enhanced Power Package
Specified from -40ºC to +125ºC junction and 85ºC maximum
ambient temperatures
3 Applications
The AS7620 is suitable for Industrial 24VDC applications like PLCs,
robotics; Home Security and Building Control applications; Solid-
state utility meters; Signage and LED column power; and Sensor
interfaces.
VIN
LDO
Temp
Level
Shifter
SHDN
FB
Hysteretic
Controller
Soft-Start
I_SENSE
LX
+
-
ILIM
V_REF
PG
+
-
PF
AS7620
+
VEPF
-
www.ams.com/DC-DC_Step-Up/AS7620
Revision 1.18
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