Data Sheet
12V TLynxTM: Non-isolated DC-DC Power Modules
July 24, 2009
4.5 – 14Vdc input; 0.69Vdc to 5.5Vdc output; 20A output current
VIN+
MODULE
16
14
12
10
8
Rpullup1
24.9K
Upper Limit
I
PWM Enable
ON/OFF
ON/OFF
+
Q2
6
23K
22K
V
ON/OFF
12.1K
4
Q1
Lower Limit
2
GND
_
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Figure 43. Circuit configuration for using negative
On/Off logic.
Output Voltage (V)
Figure 44. Output Voltage vs. Input Voltage Set
Point Area plot showing limits where the output
voltage can be set for different input voltages.
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.
Without an external resistor between Trim and GND
pins, the output of the module will be 0.69Vdc. To
calculate the value of the trim resistor, Rtrim for a
desired output voltage, use the following equation:
⎡
⎤
6.9
Vo − 0.69
Rtrim =
kΩ
⎢
⎥
⎦
Over Temperature Protection
(
)
⎣
To provide protection in a fault condition, the unit is
equipped with a thermal shutdown circuit. The unit will
shutdown if the overtemperature threshold of 135oC is
exceeded at the thermal reference point Tref . The
thermal shutdown is not intended as a guarantee that
the unit will survive temperatures beyond its rating.
Once the unit goes into thermal shutdown it will then
wait to cool before attempting to restart.
Rtrim is the external resistor in kΩ
Vo is the desired output voltage.
Table 1 provides Rtrim values required for some
common output voltages.
Table 1
VO, set (V)
0.7
Rtrim (KΩ)
690
Input Undervoltage Lockout
1.0
1.2
1.5
1.8
2.5
3.3
5.0
22.26
13.53
8.519
6.216
3.812
2.644
1.601
At input voltages below the input undervoltage lockout
limit, the module operation is disabled. The module will
begin to operate at an input voltage above the
undervoltage lockout turn-on threshold.
Output Voltage Programming
The output voltage of the 12V TLynxTM module can be
programmed to any voltage from 0.69dc to 5.5Vdc by
connecting a resistor between the Trim and GND pins
of the module. Certain restrictions apply on the output
voltage set point depending on the input voltage.
These are shown in the Output Voltage vs. Input
Voltage Set Point Area plot in Fig. 44. The Upper Limit
curve shows that for output voltages of 0.9V and lower,
the input voltage must be lower than the maximum of
14V. The Lower Limit curve shows that for output
voltages of 3.3V and higher, the input voltage needs to
be larger than the minimum of 4.5V.
By using a ±0.5% tolerance trim resistor with a TC of
±100ppm, a set point tolerance of ±1.5% can be
achieved as specified in the electrical specification.
Remote Sense
The 12V TLynxTM power modules have a Remote
Sense feature to minimize the effects of distribution
losses by regulating the voltage between the S+ and
S– pins. The voltage between the S– and GND pins of
the module must not drop below –0.2V. If Remote
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