nd12s0a0v40pnfa Delta Electronics, Inc., nd12s0a0v40pnfa Datasheet - Page 8

• Manufacturer Part Number: nd12s0a0v40pnfa
• Description: Delphi Nd Series Non-isolated Point Of Load Dc/dc Modules 8.0v~13.8vin, 0.9v~5.0vout, 40a
• Manufacturer: Delta Electronics, Inc.

FEATURES DESCRIPTIONS (CON.)
Output Voltage Programming
The output voltage of the ND40 converter can be
programmed to any voltage between 0.9Vdc and 5.0Vdc
by connecting one resistor (shown as Rtrim in Figure 26)
between the TRIM+ and Trim
Without this external resistor, the output voltage of the
module is 0.6 Vdc. To calculate the value of the resistor
Rtrim for a particular output voltage Vout, please use the
following equation:
Rtrim is the external resistor in Ω
Vout is the desired output voltage
Figure 26: Circuit configuration for programming output
voltage using an external resistor
Table 1 provides Rtrim values required for some common
output voltages. By using a trim resistor with 0.1%
tolerance and TCR of ±25ppm, set point tolerance of ±1%
can be achieved as specified in the electrical specification.
Rs
DS_ND40A_08072008
On/Off
Vin
GND
(
Ω
)
Table 1
=
Trim+
Trim-
Vout
Vo
Vout (V)
1200
0.9
1.0
1.2
1.5
1.8
2.5
3.3
5.0
Rtrim
−
0
6 .
Rtrim (Ω)
631.579
444.444
272.727
1.333K
RL
4K
3K
2K
1K
－
pins of the module.
Voltage Margining
Output voltage margining can be implemented in the
ND40 converter by connecting a resistor, R
between Trim+ pin and Trim
output voltage, and by connecting a resistor, R
between the Trim+ pin and the output pin for
margining-down.
configuration for output voltage margining. If unused,
leave the trim pin unconnected. A calculation tool is
available from the evaluation procedure which computes
the values of R
voltage and margin percentage.
Figure 27: Circuit configuration for output voltage margining
Test Setup of Output Ripple and Noise, and
Start-up Transient
The measurement set-up outlined in Figure 28 has been
used for output voltage ripple and noise measurement on
NE40 series converters.
Note: Use a 10μF tantalum and 1μF capacitor. Scope
measurement should be taken by using a BNC
connector.
Figure 28: output ripple and noise, start-up transient test setup
On/Off
Vin
GND
Trim+
Trim-
Vo
Co,min=300μF ceramic capacitors
Rtrim
margin-up
Figure
and R
Q1
Q2
Rmargin-down
Rmargin-up
margin-down
－
27
pin for margining-up the
shows
for a specific output
the
margin-down
margin-up
circuit
8
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