Data Sheet
Austin MicroLynxTM 12V SMT Non-isolated Power Modules:
10 – 14Vdc input; 0.75Vdc to 5.5Vdc Output; 5A output current
April 1, 2008
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
Feature Description
Remote On/Off
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.
The Austin MicroLynxTM SMT 12V 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 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 27).
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.
When the transistor Q1 is in the OFF state, the power
module is ON (Logic Low on the On/Off pin 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 =10 -
14V and the maximum IOn/Off = 1mA.
Overtemperature Protection
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 Tref2, (see Figure 31) exceeds
140oC (typical), but the thermal shutdown is not intended
as a guarantee that the unit will survive temperatures
beyond its rating. The module will automatically restarts
after it cools down.
VIN(+)
Lynx-series Module
IOn/Off
On/Off
Pin
Enable
Css
20k
20k
GND
Figure 27. Remote On/Off Implementation
Remote On/Off can also be implemented using open-
collector logic devices with an external pull-up resistor.
Figure 28a shows the circuit configuration using this
approach. Pull-up resistor, Rpull-up, for the configuration
should be 68k (+/-5%) for proper operation of the 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
_
Feature Descriptions (continued)
Figure 27a. Remote On/Off Implementation using
logic-level devices and an external pull-up resistor
Output Voltage Programming
The output voltage of the Austin MicroLynxTM 12V can be
programmed to any voltage from 0.75Vdc to 5.5Vdc by
Overcurrent Protection
LINEAGE POWER
12
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
