GE Industrial Solutions Zephyr Non-Isolated SMT - Manual (Page 16)

Zephyr Non-Isolated SMT DC-DC Power Module:
0.8V to 3.5V @ 20A Output, 5V to 12V Input
LINEAGE POWER 16
Data Sheet
March 31, 2010
Output control
There are two ways to set the output voltage of the Zephyr:
1. A resistor calculated from the following equation can be inserted between V
ADJUST
+
pin and V
ADJUST
−
pin.
OUT
OUT
ADJ
V
V
R
−
− ⋅
=
3 . 3
35 . 11 44 . 13
[k
Ω
] (1)
or
( )
ADJ
ADJ
OUT
R
R
V
+
+ ⋅
=
44 . 13
44 . 3 3 . 3
[V] (2)
For example, to get the output voltage of 2.5V, R
ADJ
= 27.8 k
Ω, the closest standard resistor of 27.7 kΩ
should be attached between these two pins.
Shorting and opening of these pins will give the output voltage of 0.844V and 3.30V, respectively. For the
output voltage beyond this range (up to
± %5), the use of T
RIM
pin is recommended.
The additional output voltage error due to the tolerance R
ADJ_TOL
[%] of R
ADJ
[k
Ω] is described as follows.
100 1
100
1 44 . 13
100
1 44 . 3
44 . 3
44 . 13
%
_
_
_
⋅
⎟
⎟
⎟
⎟
⎟
⎠
⎞
⎜
⎜
⎜
⎜
⎜
⎝
⎛
−
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
± ⋅ +
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
± ⋅ +
⋅
+
+
= ±
TOL ADJ
ADJ
TOL ADJ
ADJ
ADJ
ADJ
RADJ OUT
R
R
R
R
R
R
V [%] (3)
This error should be added to the error given in the “Output Voltage Set Point” section of Table 3 to get
the total DC output voltage error.
2. An external voltage V EXT [V] can be applied between V ADJUST
+
pin and V ADJUST
−
pin to control output
voltage. The relation between V
OUT
and V
EXT
is described as follows.
44 . 13
10 35 . 11
EXT
OUT
V
V
⋅ +
=
[V] (4)
Therefore, in order to set the output voltage to 2.5V, V
EXT = 2.23V. The equation (4) is valid even when
specified external voltage (such as DAC) is applied between V
ADJUST
+ and V
ADJUST
−
. Table 5 shows
voltage identification code with each corresponding voltage V EXT supplied from standard DAC, as well as
resulting output voltages of the module V OUT calculated from the equation (4). Note that if the V ADJUST +
and V ADJUST
- pins are open circuit, V
OUT
= 3.3V (default value).