Data Sheet
Austin MicroLynxTM SMT Non-isolated Power Modules:
June 24, 2008
3.0 – 5.8Vdc input; 0.75Vdc to 4.0Vdc Output; 5A output current
Feature Description
Overcurrent Protection
Remote On/Off
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
The Austin MicroLynxTM SMT power modules feature an
On/Off pin for remote On/Off operation of the module. If
not using the remote On/Off pin, leave the pin open
(module will be On). The On/Off pin signal (Von/Off) is
referenced to ground. To switch the module on and off
using remote On/Off, connect an open collector pnp
transistor between the On/Off pin and the VIN pin (See
Figure 29).
current-limiting circuitry and can endure current limiting
continuously. At the point of current-limit inception, the
unit enters hiccup mode. The unit operates normally once
the output current is brought back into its specified range.
The typical average output current during hiccup is 2A.
When the transistor Q1 is in the OFF state, the power
module is ON (Logic Low on the On/Off of the module)
and the maximum Von/off of the module is 0.4 V. The
maximum allowable leakage current of the transistor
when Von/off = 0.4V and VIN = VIN,max is 10μA. During a
logic-high when the transistor is in the active state, the
power module is OFF. During this state VOn/Off = 2.5V
to 5.8V and the maximum IOn/Off = 1mA.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout
limit, module operation is disabled. The module will begin
to operate at an input voltage above the undervoltage
lockout turn-on threshold.
Overtemperature Protection
VIN(+)
Lynx-Series Module
To provide over temperature protection in a fault
condition, the unit relies upon the thermal protection
feature of the controller IC. The unit will shutdown if the
thermal reference point Tref, exceeds 150oC (typical), but
the thermal shutdown is not intended as a guarantee that
the unit will survive temperatures beyond its rating. The
module will automatically restart after it cools down.
Q1
IOn/Off
On/Off
Pin
Enable
Css
20k
14k
GND
Figure 29. Remote On/Off Implementation.
Remote On/Off can also be implemented using open-
collector logic devices with an external pull-up resistor.
Figure 30 shows the circuit configuration using this
approach. Pull-up resistor Rpull-up, for the configuration
should be 5k (+/- 5%) for proper operation of module over
the entire temperature range.
VIN+
MODULE
R
pull-up
I
ON/OFF
ON/OFF
+
PWM Enable
V
ON/OFF
R1
R2
Q2
CSS
Q1
GND
_
Figure 30. Remote On/Off Implementation using
logic-level devices and an external pull-up resistor.
LINEAGE POWER
13
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
