BCP-5-3.3-D24 Datasheet, PDF (6/12 Pages) List of Unclassifed Manufacturers – Dual Output Mixed Voltage, BCP Models

XCP Series
75W, DUAL OUTPUT, MIXED-VOLTAGE DC/DC CONVERTERS
Output Trimming
Both the 5V and 3.3V outputs of the BCP Series can be independently
trimmed via a trimpot (Figure 3A) or a single fixed resistor as shown (Figures
3B & 3C). The trimpot can be used to determine the value of a single fixed
resistor. A single fixed resistor can increase or decrease the output voltage
depending on its connection. Fixed resistors should be metal-film types with
absolute TCR’s less than 100ppm/°C to ensure stability.
1
–INPUT
4
+INPUT
10
+3.3V OUTPUT
3.3V TRIM ₈
3.3V RETURN ⁹
7
+5V OUTPUT
5V TRIM ₅
6
5V RETURN
20kΩ
5-22
TURNS
20kΩ
5-22
TURNS
+3.3V
LOAD
+5V
LOAD
Figure 3A. Trim Connections Using a Trimpot
A resistor connected from the Trim Pin (pin 5 for 5V trim, pin 8 for 3.3V trim)
to the appropriate Return (pin 6 for 5V trim, pin 9 for 3.3V trim) will increase
the output voltage.
1
–INPUT
4
+INPUT
10
+3.3V OUTPUT
8
3.3V TRIM
3.3V RETURN ⁹
7
+5V OUTPUT
5
5V TRIM
6
5V RETURN
+3.3V
TRIM
UP
+5V
TRIM
UP
+3.3V
LOAD
+5V
LOAD
Figure 3B. Increase Output Voltage Trim Connections Using a Fixed Resistor
A single resistor connected from the Trim Pin (pin 5 for 5V trim, pin 8 for
3.3V trim) to its appropriate +Output (pin 7 for 5V trim, pin 10 for 3.3V trim)
will decrease the output voltage.
1
–INPUT
4
+INPUT
10
+3.3V OUTPUT
3.3V TRIM
8
3.3V RETURN ⁹
7
+5V OUTPUT
5V TRIM
5
6
5V RETURN
+3.3V
TRIM
DOWN
+5V
TRIM
DOWN
+3.3V
LOAD
+5V
LOAD
Figure 3C. Decrease Output Voltage Trim Connections Using a Fixed Resistor
Table 1 shows the typical fixed Trim Resistor values for output voltage
changes of 0 through 10%. Trim adjustment greater than 10% can have an
adverse affect on the converter’s performance and is not recommended.
3.3V
Trim Down
0%
–
1%
47.81k
2%
22.32k
3%
13.82k
4%
9.57k
5%
7.02k
6%
5.320k
7%
4.10k
8%
3.19k
9%
2.48k
10%
1.92k
3.3V
Trim Up
–
27.93k
12.78k
7.73k
5.21k
3.69k
2.68k
1.96k
1.42k
1.00k
0.66k
5V
Trim Down
–
189.75k
91.06k
58.17k
41.72k
31.85k
25.27k
20.57k
17.05k
14.31k
12.12k
5V
Trim Up
–
61.68k
28.34k
17.23k
11.68k
8.34k
6.12k
4.53k
3.34k
2.42k
1.68k
Table 1. Percentage of Output Voltage Change vs Trim Resistor Value (Ohms)
The following equations mathematically depict:
Output Voltage for a given Trim Resistor
Trim Resistor for a given Output Voltage
5 Volt Trim Up
1
VO = 5.0 +
0.30RT_UP (kΩ) + 1.5
RT_UP(kΩ) =
1
(0.3VO) – 1.50
–4.99
5 Volt Trim Down
VO = 1.25
1.14
+1
1
0.38 +
RT_DOWN (kΩ) + 4.99
RT_DOWN (kΩ) =
1
1.14
(0.8VO) – 1
–0.38
–4.99
3.3 Volt Trim Up
1
VO = 3.30 +
RT_UP (kΩ) + 2.37
RT_UP(kΩ) =
1
VO – 3.3
–2.37
3.3 Volt Trim Down
VO = 1.23
1.23 +
2.07
+1
1
RT_DOWN (kΩ)+ 2.37
RT_DOWN (kΩ) =
1
2.07 _–1.23
VO
1.23
–1
–2.37
Note: Resistor values are in kΩ. Accuracy of adjustment is subject
to tolerances of resistor values and factory-adjusted output accuracy.
VO = desired output voltage.
Case Connection
BCP DC/DC's do not have their metal baseplate connected to one of the input
pins. The "uncommitted" baseplate is connected to pin 2 which, depending
upon your system configuration, should be connected to either +Input (pin 4),
–Input (pin 1), Output Returns (pins 6 & 9), or earth ground.
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