19-1832; Rev 0a; 1/01
-48V Simple Swapper Hot-Swap Switches
The MAX5911/MAX5912 are fully integrated hot-swap
switches for negative supply rails. These devices allow
the safe insertion and removal of circuit cards into live
backplanes or ports without causing problematic glitch-
es on the negative power-supply rail. They also monitor
various circuit parameters and disconnect the load if a
fault condition occurs, alerting the host with a logic-level
FAULT output. The MAX5911/MAX5912 operate over a
voltage range of -16V to -65V and are designed to permit
hot plugging of an IP phone into a hub, but are not limit-
ed to that operation.
During startup, an internal power FET regulates the cur-
rent between the backplane power source and the load
to 280mA for MAX5911 and 415mA for MAX5912. After
startup, the FET is fully enhanced to reduce its on-resis-
tance. To ensure robust operation, the MAX5911/
MAX5912 contain built-in safety features that prevent
damage to the internal FET. They include an enable
input, which responds to positive logic signals (+3.3V or
+5V), allowing the host system to disconnect the load.
ENABLE is also used to reset the device after a latching
fault condition occurs.
The MAX5911/MAX5912 Simple Swapper™ hot-swap
ICs monitor four parameters for these fault conditions:
undervoltage lockout (UVLO), power-not-good, zero-
current detection, and thermal shutdown. These
devices are available in the extended temperature
range, -40°C to +85°C. The MAX5911 and MAX5912
come in 8-pin and 16-pin SOIC packages, respectively.
Typical Operating Circuit
o Provides Safe Hot Swap for -16V to -65V Power
o 280mA Current Limit for MAX5911
o 415mA Current Limit for MAX5912
o Zero-Current Load Disconnect
o Integrated Power FET
o Status Output Reports Fault Condition
o Internal Switch-Protection Circuitry
o Built-In Thermal Shutdown
o DGND Can Vary Up to ±5V with Respect to AGND
-40°C to +85°C
-40°C to +85°C
Simple Swapper is a trademark of Maxim Integrated Products, Inc.
*THESE PINS ARE NOT INTERNALLY CONNECTED.
________________________________________________________________ Maxim Integrated Products 1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.