Datasheet

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MAX14626
High-Voltage Reverse-Input-Capable 4–20mA
Current Loop Protector
Detailed Description
The MAX14626 current loop protector features a current-
limit switch to prevent damage to the sensor devices due
to faulty current loop conditions. The current-limit switch
features a 25I (typ) on-resistance and operates from a
+2.3V to +36V input voltage range. The accurate current
limit is set to 30mA, making the part ideal for protecting
the sensor reading devices.
The MAX14626 handles an overcurrent event in a con-
tinuous current-limit mode. Additional safety features
include thermal shutdown to prevent overheating and
reverse input blocking to protect from being reverse con-
nected into the sensor.
Reverse Input Protection
The device features reverse input protection to protect
the downstream sensor. When a reverse input voltage is
detected, control circuitry turns off the internal FET and
isolates the output from the input.
Thermal Shutdown
The device enters thermal shutdown when the die tem-
perature exceeds +150NC (typ). In thermal shutdown, the
internal FETs are turned off. When the die temperature
drops by 20NC, the device turns back on automatically.
Applications Information
Figure 1 shows the device in a 4–20mA current loop sensor
application.
Exposed Pad and Layout Concerns
Connect the exposed pad to a large ground plane to
maximize thermal performance. The exposed pad is not
intended as an electrical connection point.
To optimize the switch response time to output short-
circuit conditions, it is very important to keep all traces
as short as possible to reduce the effect of undesirable
parasitic inductance.
Functional Diagram
REF SUPPLY
OUT
GND
IN
CONTROL AND
PROTECTION
CURRENT LIMIT
GATE CONTROL
MAX14626