Data Sheet
April 1, 2008
Austin Lynx
TM
SIP Non-isolated Power Modules, Programmable:
3.0Vdc – 5.5Vdc input; 0.75 to 3.63Vdc Output; 10A Output Current
The output voltage of the Austin Lynx
TM
SIP can be
programmed to any voltage from 0.75 Vdc to 3.3 Vdc by
connecting a single resistor (shown as Rtrim in Figure
31) between the TRIM and GND pins of the module.
Without an external resistor between the TRIM pin and
the ground, the output voltage of the module is 0.7525
Vdc. To calculate the value of the resistor
Rtrim
for a
particular output voltage Vo, use the following equation:
Feature Description
Remote On/Off
The Austin Lynx
TM
power modules feature an an On/Off
pin for remote On/Off operation. The On/Off pin is pulled
high with an external pull-up resistor (typical Rpull-up =
68k, ± 5%) as shown in Fig. 28. 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 1.5Vdc. 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.
VIN+
R
pull-up
I
ON/OFF
ON/OFF
+
V
ON/OFF
PWM Enable
R1
Q2
R2
GND
_
CSS
⎡
21070
⎤
Rtrim
=
⎢
−
5110
⎥
Ω
⎣
Vo
−
0.7525
⎦
For example, to program the output voltage of the
TM
Austin Lynx module to 1.8 Vdc,
Rtrim
is calculated is
follows:
MODULE
⎤
⎡
21070
Rtrim
=
⎢
−
5110
⎥
Ω
⎦
⎣
1.8
−
0.7525
Rtrim
=
15.004
k
Ω
V
IN
(+)
V
O
(+)
Q1
ON/OFF
TRIM
R
trim
LOAD
Figure 29. Circuit configuration for using positive
logic On/OFF.
GND
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 3A.
Figure 31. Circuit configuration for programming
output voltage using an external resistor.
Table 1 provides
Rtrim
values for some common output
voltages
Table 1
V
O, set
(V)
0.7525
1.2
1.5
1.8
2.5
3.3
Rtrim (KΩ)
Open
41.973
23.077
15.004
6.947
3.160
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
To provide protection in a fault condition, the unit is
equipped with a thermal shutdown circuit. The unit will
shutdown if the thermal reference point T
ref
, exceeds
125
o
C (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.
By using a 1% tolerance trim resistor, set point
tolerance of ±2% is achieved as specified in the
electrical specifications. The POL Programming Tool,
available at
www.lineagepower.com
under the Design
Tools section, helps determine the required external
trim resistor needed for a specific output voltage
Output Voltage Programming
LINEAGE
POWER
12
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
