AS7620_1 Datasheet, PDF (1/16 Pages) ams AG – 500mA Hysteretic High Voltage Step-Down Converter with Dual Power Monitor

Datasheet
AS7620
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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