Datasheet

Advance Data Sheet: iAF Series – Non-isolated SMT Power Module
©2011 TDK Innoveta Inc.
iAF12_Full_Datasheet_10032012.doc 10/3/2012
℡
(877) 498
-
0099
16/18
Output Voltage Adjustment: The output voltage
of
the power module may be adjusted by using an
external resistor connected between the Vout trim
terminal and GND terminal. If the output voltage
adjustment feature is not used, trim terminal should be
left open. Care should be taken to avoid injecting
noise into the power module’s trim pin
Trim
Vout(+)
Rup
GND
Circuit to increase output voltage
With a resistor between the trim and GND terminals,
the output voltage is adjusted up. To adjust the output
voltage from Vo,nom to Vo,up the trim resistor should
be chosen according to the following equation:
Ru
Vref F⋅( )
Voup Vref−( )






:=
ohm
The values of Vref and F are found in the electrical
data section for the power module of interest. The
maximum power available from the power module is
fixed. As the output voltage is trimmed up, the
maximum output current must be decreased to
maintain the maximum rated power of the module.
e.g. Vo = 1.8V
Ru
0.69 10000⋅
1.8
0.69
−
(
)






:=
Vout (V) Ru (Kohm)
0.7 690
1.2 13.5
1.5 8.52
1.8 6.21
2.5 3.81
3.3 2.64
5.0 1.6
Voltage Sequencing:
Some iAF power modules include a voltage sequence
feature. The voltage sequence feature enables the
user to implement various types of power up and
power down sequencing schemes including sequential
startup, ratiometric startup, and simultaneous startup.
If the sequencing feature is not being used the pin
should be left open or tied to Vin. When the voltage
sequencing feature is used the pre-bias immunity
feature is disabled.
To use the voltage sequence feature, the module
should be set to an On state using the on/off feature.
The input voltage should be applied and in the
specified operating range for 10mS during which a
50mV voltage potential should be maintained on the
sequence pin. After the 10mS interval, an analog
voltage can be applied to the sequence pin and the
module’s output will track the applied voltage on a one
to one basis until the output reaches its set point
voltage. The final sequence voltage must be higher
than the module set point. For sequential shut down,
the sequence pin voltage should be lowered. The
module will decrease its output voltage on a one to
one basis.
The voltage sequencing circuit has a brief internal
response time between the voltage appearing on the
sequence pin and impacting the output voltage. If
necessary, the impact of the time delay can be
minimized by limiting the slew rate of the voltage on
the sequence pin to less than 0.5 V/ms.
For additional assistance using the voltage
sequencing function, please contact TDK Innoveta
technical support.