MAX5923 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – +60V Simple Swapper Hot-Swap Switch

19-2850; Rev 0; 4/03
+60V Simple Swapper Hot-Swap Switch
General Description
The MAX5923 is a fully integrated Simple Swapper™
hot-swap switch for positive supply rails. The device
allows the safe insertion and removal of circuit cards
into live backplanes or ports without causing glitches
on the power-supply rail. The device also monitors vari-
ous circuit parameters and disconnects the load if a
fault condition occurs, alerting the host with a logic-
level FAULT output. The MAX5923 operates over the
+16V to +60V input voltage range.
During startup, an integrated 0.45Ω power MOSFET
regulates the current and voltage between the back-
plane power source and the load. After startup, the
MOSFET is fully enhanced to reduce its on-resistance.
To ensure robust operation, the MAX5923 contains
built-in safety features that monitor fault conditions and
prevent damage to the internal MOSFET.
The MAX5923 monitors three parameters for fault condi-
tions: zero current, overcurrent, and thermal overload.
The output overcurrent limit counts the time the MAX5923
spends in an overcurrent condition and shuts down the
pass transistor if the current limit is exceeded for the over-
current time limit. The zero-current detection counts the
time the output current is below the zero-current threshold
and shuts down the pass transistor if the counter reaches
the zero-current time limit. The thermal monitoring feature
shuts down the pass transistor if the die temperature
reaches the overtemperature limit. A fault logic output
indicates when an overtemperature or an overcurrent
condition has occurred and a zero-current logic output
indicates if there is a zero-current condition.
An undervoltage detection circuitry keeps the pass tran-
sistor off until the input voltage is above the undervoltage
lockout (UVLO) threshold, which is internally set or can be
set externally with a resistive divider. A power-OK (POK)
output is provided to signal when the output voltage has
reached to within 0.75V of the input voltage. An Enable
input allows the host system to disconnect the system
from the load and/or reset a fault condition by toggling
Enable.
The MAX5923 is available in a 20-pin TSSOP package
and operates in the extended -40°C to +85°C tempera-
ture range.
Applications
Network Routers/Switches Servers
Current Limiter
Industrial Equipment
Features
o Wide Operating Input Range: +16V to +60V
o 0.45Ω Integrated Power Switch
o Programmable Output Current Up to 800mA
o Over/Undercurrent-Limit Detection
o Input Logic Signals Compatible with 1.8V to 5V
CMOS Logic
o Separate Analog and Digital Grounds with Up to
±4V Offset
o Power-OK Status Output
o Overcurrent Protection with Status Outputs
o Built-In Thermal Shutdown
o Internal Switch Protection Circuitry
o Current-Limit Foldback with Timeout and Duty-
Cycle Control
o Latch or Autorestart Fault Management
PART
MAX5923EUP
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
Typical Operating Circuit
+16V TO +60V
RSENSE
ON
OFF
IN
OUT
VDIG
DRAIN
MAX5923
UVLO
LATCH
EN
AGND_S
ZC_EN
ZC
FAULT
POK
DGND
D1
RPU
RPU
RPU
+1.65V TO +5.5V
ALL SIGNAL AND DIGITAL INPUTS/OUTPUTS ARE REFERENCED TO DGND.
DGND CAN BE ±4V FROM AGND_S.
Simple Swapper is a trademark of Maxim Integrated Products, Inc. Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.