88 Tyco Electronics Corp.
Advance Data Sheet
August 1997
5 Vdc Input; 1.5 Vdc to 3.3 Vdc Output; 15 A
NH050x-LP Series Power Modules:
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment (Trim)
Output voltage set-point adjustment allows the output
voltage set point to be increased or decreased by con-
necting an external resistor between the TRIM pin and
either the VO pin (decrease output voltage) or GND pin
(increase output voltage). The trim range for modules
that produce 2.5 V OUT or greater is ±10% of VO, nom. The
trim range for modules that produce less than 2.5 VOUT
is +20%, –0%.
Connecting an e xternal resistor (Rtrim-down) between the
TRIM and VO pin decreases the output voltage set
point as defined in the following equation.
For the F (3.3 VOUT) module:
For the G (2.5 VOUT) module:
Note: Output voltages below 2.5 V cannot be trimmed
down.
Connecting an external resistor (Rtrim-up) between the
TRIM and GND pins increases the output voltage set
point to VO, adj as defined in the following equation.
For the G (2.5 VOUT) module:
For all other modules:
If not using the trim feature, leave the TRIM pin open.
Overtemperature Shutdown
To provide additional protection in a fault condition, the
unit is equipped with a nonlatched thermal shutdown
circuit. The shutdown circuit engages when Q32
exceeds approximately 120 °C. The unit attempts to
restart when Q32 cools down. The unit cycles on and
off if the fault condition continues to exist. Recovery
from shutdown is accomplished when the cause of the
overheating condition is removed.
Parallel Operation
F or additional power requirements, the power modules
can be configured for parallel operation with forced
load sharing (see Figure 8).
Good layout techniques should be observed for noise
immunity. To implement forced load sharing, the follow-
ing connections must be made:
■The PARALLEL pins of all units must be connected
together. The paths of these connections should be
as direct as possible.
■Connect the SYNC OUT pin of one module to the
SYNC IN pin of another module according to the
Module Synchronization section on the next page.
■All remote-sense pins must be connected to the
power bus at the same point, i.e., connect all
SENSE(+) pins to the (+) side of the power b us at the
same point and all SENSE(–) pins to the (–) side of
the power b us at the same point. Close pro ximity and
directness are necessary for good noise immunity.
8-581(C).b
Figure 8. Wiring Configuration for Parallel Opera-
tion
Rtrim-down 18.23
VOVO adj,–
------------------------------ 47.2–
kΩ=
Rtrim-down 6.98
VOVO adj,–
------------------------------ 24–
kΩ=
Rtrim-up 28
VO adj,VO–
------------------------------ 10–
kΩ=
Rtrim-up 28
VO adj,VO–
------------------------------ 33.2–
kΩ=
VOUT
PARALLEL
SENSE(+)
SENSE(–)
SYNC
IN
SYNC
OUT
VIN
VOUT
PARALLEL
SENSE(+)
SENSE(–)
VIN
SYNC
IN
SYNC
OUT
MA