Datasheet

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R
SET
+ R
O
V
R
V
O
* V
MIN
* R
P
(1)
1
3
4
5
9
10
8
7
6
2
C
I
100 µF
Track
−Sense
+V
I
−V
I
NEN
PTB78560A
PEN
+Sense
V
O
Bus
V
O
Adjust
V
O
COM
R
SET
−V
I
+V
I
C
O
220 µF
PTB78560A , PTB78560B
PTB78560C
SLTS249 – JUNE 2005
Table 1. Standard Values of R
SET
for Common Output Voltages
PTB78560A PTB78560B PTB78560C
V
O
(Required) R
SET
V
O
(Actual) R
SET
V
O
(Actual) R
SET
V
O
(Actual)
1.8 V – – Open 1.802 V – –
2 V – – 200 k Ω 2.004 V – –
2.5 V – – 40.2 k Ω 2.498 V – –
3.3 V – – 5.36 k Ω 3.300 V – –
3.6 V Open 3.611 V 309 Ω 3.600 V – –
5 V 14.3 k Ω 5.005 V – – – –
9 V – – – – Open 9.015 V
10 V – – – – 73.2 k Ω 9.993 V
12 V – – – – 9.09 k Ω 12 V
13.2 V – – – – 0 Ω 13.23 V
For other output voltages, the value of the required adjust resistor may be calculated using Equation 1 .
Table 2 gives the output voltage adjust range and the required equation constants for the converter model
selected. To calculate the required value of R
SET
, simply locate the applicable constants and substitute these
into the formula along with the desired output voltage.
Table 2. Adjust Ranges and Equation Constants
Model # PTB78560A PTB78560B PTB78560C
V
R
1.24 V 1.24 V 2.5 V
R
O
49.91 k Ω 36.55 k Ω 37.27 k Ω
R
P
30.1 k Ω 24.9 k Ω 22.1 k Ω
V
MIN
3.61 V 1.8 V 9.02 V
V
MAX
5.5 V 3.6 V 13.2 V
Figure 22. Output Voltage Adjustment
14
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