Lineage Power 9
Data Sheet
March 2008 18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 33 W to 66 W
JC050F, JC075F, JC100F Power Modules: dc-dc Converters;
Feature Descriptions
Remote On/Off
Two remote on/off options are available. Positive logic
remote on/off 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 turns the module off dur-
ing a logic high and on during a logic low. Negative
logic (code suffix “1”) is the factory-preferred configura-
tion.
To turn the power module on and off, the user must
supply a switch to control the voltage between the
on/off terminal and the V
I(–) terminal (Von/off). The
switch can be an open collector or equivalent (see
Figure 16). A logic low is V
on/off = 0 V to 1.2 V. The
maximum I
on/off during a logic low is 1 mA. The switch
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum V
on/off generated by
the power module is 15 V. The maximum allowable
leakage current of the switch at V
on/off = 15 V is 50 μA.
If not using the remote on/off feature, do one of the fol-
lowing:
n For negative logic, short ON/OFF pin to VI(–).
n For positive logic, leave ON/OFF pin open.
8-720 c
Figure 16.Remote On/Off Implementation
Remote Sense
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connections. The voltage between the remote-sense
pins and the output terminals must not exceed the out-
put voltage sense range given in the Feature Specifica-
tions table, i.e.:
[V
O(+) – VO(–)] – [SENSE(+) – SENSE(–)] ≤ 0.5 V
The voltage between the V
O(+) and VO(–) terminals
must not exceed 3.8 V. This limit includes any increase
in voltage due to remote-sense compensation and out-
put voltage set-point adjustment (trim), see Figure 17.
If not using the remote-sense feature to regulate the
output at the point of load, then connect SENSE(+) to
V
O(+) and SENSE(–) to VO(–) at the module.
8-651 m
Figure 17. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Output Voltage Set-Point Adjustment
(Trim)
Output voltage trim allows the user to increase or
decrease the output voltage set point of a module. This
is accomplished by connecting an external resistor
between the TRIM pin and either the SENSE(+) or
SENSE(–) pins. With an external resistor between the
TRIM and SENSE(–) pins (R
adj-down), the output voltage
set point (V
O, adj) decreases (see Figure 18). The fol-
lowing equation determines the required external-resis-
tor value to obtain a percentage output voltage change
of Δ%.
The test results for this configuration are displayed in
Figure 19. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (R
adj-up), the output voltage set
point (V
O, adj) increases (see Figure 20).
SENSE(+)
V
O(+)
SENSE(–)
V
O(–)
V
I(–)
+
–
I
on/off
ON/OFF
V
I(+)
LOAD
Von/off
V
O
(+)
SENSE(+)
SENSE(–)
V
O
(–)
V
I
(+)
V
I
(-)
I
O
LOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY
I
I
CONTACT
RESISTANCE
R
adj-down
100
Δ%
----------2–
⎝⎠
⎛⎞
kΩ=
