AS7620 Datasheet, PDF (1/2 Pages) ams AG – 500mA Hysteretic High Voltage Step-Down Converter with Dual Power Monitor

AS7620
Data Sheet
500mA Hysteretic High Voltage Step-Down Converter
with Dual Power Monitor
1 General Description
2 Key Features
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. Block Diagram
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
VEPF
Hysteretic
Controller
Soft-Start
I_SENSE
LX
+
-
V_REF
ILIM
PG
+
-
PF
AS7620
+
-
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