Data Sheet
March 27, 2008
JBW030-Series Power Module: dc-dc Converters
36-75 Vdc Input; 3.3 Vdc and 5 Vdc Outputs; 30 W
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 16). The fol-
lowing equation determines the required external-resis-
tor value to obtain an output voltage change of %
Δ.
1
–
%
Δ
-
R
adj-down
=
⎛
------------------
⎞
10 kΩ
⎝
%
Δ
⎠
For example, to lower the output voltage by 20%, the
external resistor value must be:
1
–
0.2
-
R
adj-down
=
⎛
----------------
⎞
10 kΩ =
⎝
0.2
⎠
Feature Descriptions
(continued)
Remote On/Off
(continued)
V
I
(+)
V
I
(-)
–
V
on/off
SENSE(+)
V
O
(+)
REMOTE
ON/OFF
LOAD
V
O
(–)
SENSE(–)
+
I
on/off
8-720(C).h
Figure 14. Remote On/Off Implementation
40.00
kΩ
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
(+) – V
O
(–)] – [SENSE(+) – SENSE(–)]
≤
0.2 V
The voltage between the V
O
(+) and V
O
(–) terminals
must not exceed the minimum output overvoltage shut-
down voltage as indicated in the Feature Specifications
table. This limit includes any increase in voltage due to
remote-sense compensation and output voltage set-
point adjustment (trim). See Figure 15.
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 V
O
(–) at the module.
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 17). The following
equations determine the required external-resistor
value to obtain an output voltage change of %
Δ.
JBW030A:
1 + %Δ
V
O, nom
-
R
adj-up
=
⎛
-----------------
–
1
⎞ ⎛
------------------
⎞
10 kΩ
-
⎝
2.5
⎠ ⎝
%
Δ
⎠
For example, to increase the output voltage of the
JBW030A by 5%, the external resistor value must be:
1 + 0.05
5.0
-
R
adj-up
=
⎛
-------
–
1
⎞ ⎛
--------------------
⎞
10 kΩ = 210 kΩ
-
⎝
2.5
⎠ ⎝
0.05
⎠
JBW030F:
1 + %Δ
V
O,
nom
-
R
adj-up
=
⎛
-------------------
–
1
⎞ ⎛
------------------
⎞
10 kΩ
⎝
1.235
⎠ ⎝
%Δ
⎠
For example, to increase the output voltage of the
JBW030F by 5%, the external resistor must be:
SENSE(+)
SENSE(–)
V
I
(+)
SUPPLY
I
I
V
I
(-)
CONTACT
RESISTANCE
V
O
(–)
CONTACT AND
DISTRIBUTION LOSSES
8-651(C).m
1 + 0.05
3.3
-
-
R
adj-up
=
⎛
--------------
–
1
⎞ ⎛
--------------------
⎞
10 kΩ = 351.1 kΩ
⎝
1.235
⎠ ⎝
0.05
⎠
I
O
LOAD
V
O
(+)
Figure 15. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Lineage Power
9
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
