Data Sheet
Austin MicroLynxTM II 12V SMT Non-isolated Power Modules:
8.3 – 14Vdc input; 0.75Vdc to 5.5Vdc Output; 6A output current
May 19, 2009
Feature Description
VIN+
MODULE
R
pull-up
Remote On/Off
I
ON/OFF
Austin MicroLynxTM II 12V SMT power modules feature
an On/Off pin for remote On/Off operation. Two On/Off
logic options are available in the Austin MicroLynxTM II
12V series modules. Positive Logic On/Off signal, device
code suffix “4”, turns the module ON during a logic High
on the On/Off pin and turns the module OFF during a
logic Low. Negative logic On/Off signal, no device code
suffix, turns the module OFF during logic High and turns
the module ON during logic Low.
ON/OFF
+
PWM Enable
V
ON/OFF
R1
R2
Q2
CSS
Q1
GND
_
For positive logic modules, the circuit configuration for
using the On/Off pin is shown in Figure 28. The On/Off
pin is an open collector/drain logic input signal (Von/Off)
that is referenced to ground. During a logic-high (On/Off
pin is pulled high internal to the module) when the
transistor Q1 is in the Off state, the power module is ON.
Maximum allowable leakage current of the transistor
when Von/off = VIN,max is 10µA. Applying a logic-low
when the transistor Q1 is turned-On, the power module is
OFF. During this state VOn/Off must be less than 0.3V.
When not using positive logic On/off pin, leave the pin
unconnected or tie to VIN.
Figure 29. Circuit configuration for using negative
logic On/OFF.
Overcurrent Protection
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
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.
VIN+
MODULE
R2
Input Undervoltage Lockout
ON/OFF
Q2
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.
+
R1
V
ON/OFF
I
ON/OFF
PWM Enable
R3
R4
Overtemperature Protection
Q1
Q3
CSS
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 33) 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.
GND
_
Figure 28. Circuit configuration for using positive
logic On/OFF.
For negative logic On/Off devices, the circuit
configuration is shown is Figure 29. The On/Off pin is
pulled high with an external pull-up resistor (typical Rpull-up
= 68k, +/- 5%). When transistor Q1 is in the Off state,
logic High is applied to the On/Off pin and the power
module is Off. The minimum On/off voltage for logic High
on the On/Off pin is 2.5 Vdc. To turn the module ON,
logic Low is applied to the On/Off pin by turning ON Q1.
When not using the negative logic On/Off, leave the pin
unconnected or tie to GND.
LINEAGE POWER
12
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
