Data Sheet
June 15, 2006
HW/HC004/005/006 Series DC-DC Power Module:
18-36Vdc & 36-75Vdc Input; 1.0V-5Vdc Output; 4A - 6A Output Current
Tyco Electronics Power Systems 17
Feature Description Input Undervoltage Lockout
At input voltages below the input undervoltage lockout
limit, the module operation is disabled. The module will
only begin to operate once the input voltage is raised
above the undervoltage lockout turn-on threshold, VUV/ON.
Remote On/Off
Two remote on/off options are available. Positive logic
turns the module on during a logic high voltage on the
ON/OFF pin, and off during a logic low. Negative logic
remote On/Off, device code suffix “1”, turns the module off
during a logic high and on during a logic low.
Once operating, the module will continue to operate until
the input voltage is taken below the undervoltage turn-off
threshold, VUV/OFF.
To maintain compatibility with LW series power modules
the Remote On/Off pin is optional for the TH (through hole)
version. Standard TH modules have no On/Off pin fitted.
TH modules ordered with device code suffix “1” are
negative logic with the On/Off pin fitted.
Over Voltage Protection
The output overvoltage protection consists of circuitry that
internally clamps the output voltage. If a more accurate
output overvoltage protection scheme is required then this
should be implemented externally via use of the remote
on/off pin.
ON/OFF
VIN(+)
VIN(-)
Ion/off
Von/off
VO
COM
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 125 oC is
exceeded at the thermal reference point Tref . Once the
unit goes into thermal shutdown it will then wait to cool
before attempting to restart.
Output Voltage Programming
Trimming allows the output voltage set point to be
increased or decreased, this is accomplished by
connecting an external resistor between the TRIM pin and
either the VO(+) pin or the VO(-) pin (COM pin) .
Figure 64. Remote On/Off Implementation.
To turn the power module on and off, the user must supply
a switch (open collector or equivalent) to control the
voltage (Von/off) between the ON/OFF terminal and the VIN(-
) terminal. Logic low is 0V ≤ Von/off ≤ 1.2V. The maximum
Ion/off during a logic low is 1mA, the switch should be
maintain a logic low level whilst sinking this current.
VO(+)
VOTRIM
COM
Rtrim-down
LOAD
VIN(+)
ON/OFF
VIN(-)
Rtrim-up
During a logic high, the typical Von/off generated by the
module is 5.8V, and the maximum allowable leakage
current at Von/off = 5.8V is 10μA.
If not using the remote on/off feature:
For positive logic, leave the ON/OFF pin open.
For negative logic, short the ON/OFF pin to VIN(-). Figure 65. Circuit Configuration to Trim Output
Voltage.
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 average output current
during hiccup is 10% IO, max.
Connecting an external resistor (Rtrim-down) between the
TRIM pin and the COM pin decreases the output voltage
set point. To maintain set point accuracy, the trim resistor
tolerance should be ±0.1%.