PAF600F280-28 TDK Corporation, PAF600F280-28 Datasheet - Page 19

• Manufacturer Part Number: PAF600F280-28
• Description: 28V@21.5A
• Manufacturer: TDK Corporation

・All specifications are subject to change without notice.
PAF
Output Voltage Adjustment by external resistor or by
variable resistor
Resistor values, as well as, connecting methods for ex-
ternal resistor (R2) and external variable resistor (VR) are
described below.
In this case, using VR as remote programming resistor, re-
mote programming of output voltage can be possible.
Output voltage rate of change versus VR resistor value is
approximately 1V/kΩ. (Sensing current: about 1mA)
Also, be sure to connect remote programming resistor be-
tween +S terminal and +V terminal.
Output Voltage Adjustment by applying external
voltage
By applying external voltage at the TRIM terminal, output
voltage can be adjusted within the same output voltage
adjustment range as the output voltage adjustment by
external resistor or variable resistor. For this case, output
voltage can be determined by the formula shown below.
Table2-1 Values of External Resistor and
Fig.2-2 Example Connection of External Resistor
＋S
＋V
−V
−S
TRIM
External Resistor ： below±5% Tolerance
Variable Resistor ： below±20% Tolerance
below 1% Remain
External Resistor ： below±5% Tolerance
Variable Resistor ： below±20% Tolerance
below 1% Remain
Table2-2 Values of External Resistor and
Output Voltage = TRIM Terminal Voltage
500F24
Variable Resistor (－40% to +10% Variable)
Variable Resistor (±10% Variable )
R2
VR
R2
VR
R2
VR
×Nominal Output Voltage
12V
6.8k
12V
20k
43k
5k
6.8 k
28V
28V
50k
43k
10k
Load
＋
−
Unit： ［Ω］
Unit： ［Ω］
For applications other than the above, refer to the trim cir-
cuit below and determine external circuit and component
values.
3 Maximum Ripple and Noise
Measured value according to the specified methods based
on JEITA-9141 (Clause 7.12 and clause 7.13) which is
described in the following.
Connect according to Fig.3-1 and measure. Connect ca-
pacitors (C2: ceramic capacitor 10μF, C3: refer to table
1-1 for electrolytic capacitor values) at 50mm distance
from the output terminals. Measure at ceramic capacitor
(C2) leads as shown in Fig.3-1 using coaxial cable with
JEITA attachment. Use oscilloscope with 100MHz fre-
quency bandwidth or equivalent.
Take note that output ripple voltage and output spike noise
may vary depending on PCB wiring design.
Generally, output ripple voltage and output spike noise can
be reduced by increasing capacitance value of external
capacitor.
4 Maximum Line Regulation
Maximum value of output voltage change when input volt-
＋V
−V
＋S
＋V
−V
−S
TRIM
Fig.3-1 Measurement of Maximum Output
Fig.2-4 TRIM Circuit (For the Reference)
1.225V
Reference
Voltage
50mm
Fig.2-3 Output Voltage Adjustment by
Error Amplifier
C2
7.32k
External
Voltage
+
Ripple & Noise
Ω
applying external voltage
−
＋
C3
1.5m 50Ω
Coaxial Cable
32.4k Ω
As short as possible
Load
1kΩ
C
R
JEITA Attachment
Oscilloscope
R:50Ω
C:4700pF
Load
＋
−
＋S
−S
TRIM
B-111
PAF