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Pin Descriptions
Vin:
The positive input voltage power node to the mod-
ule, which is referenced to common
GND
.
Vout:
The regulated positive power output with respect
to the
GND
node.
GND:
This is the common ground connection for the
Vin
and
Vout
power connections. It is also the 0 VDC
reference for the control inputs.
Inhibit:
The Inhibit pin is an open-collector/drain negative
logic input that is referenced to
GND
. Applying a low-
level ground signal to this input disables the module’s
output and turns off the output voltage. When the
Inhibit
control is active, the input current drawn by the regula-
tor is significantly reduced. If the
Inhibit
pin is left
open-circuit, the module will produce an output when-
ever a valid input source is applied.
Vo Adjust:
A 0.1 W, 1 % tolerance (or better) resistor
must be connected between this pin and the
GND
pin to
set the output voltage to the desired value. The set point
range for the output voltage is from 0.8 V to 2.5 V. The
resistor required for a given output voltage may be cal-
culated from the following formula. If left open circuit,
the module output will default to its lowest output voltage
value. For further information on the adjustment of the
output voltage consult the related application note.
R
set
= 10 k · 0.8 V
V
out
– 0.8 V
– 2.49 k
The specification table gives the preferred resistor values
for a number of standard output voltages.
Vo Sense:
The sense input allows the regulation circuit to
compensate for voltage drop between the module and
the load. For optimal voltage accuracy
Vo Sense
should
be connected to
Vout
. It can also be left disconnected.
Track:
This is an analog control input that enables the
output voltage to follow an external voltage. This pin
becomes active typically 20 ms after the input voltage
has been applied, and allows direct control of the output
voltage from 0 V up to the nominal set-point voltage.
Within this range the output will follow the voltage at
the
Track
pin on a volt-for-volt basis. When the control
voltage is raised above this range, the module regulates
at its set-point voltage. The feature allows the output
voltage to rise simultaneously with other modules pow-
ered from the same input bus. If unused, the input may
be left unconnected.
Note: Due to the under-voltage lockout
feature, the output of the module cannot follow its own input
voltage during power up. For more information, consult the
related application note.
Margin Down:
When this input is asserted to
GND
, the
output voltage is decreased by 5% from the nominal. The
input requires an open-collector (open-drain) interface.
It is not TTL compatible. A lower percent change can
be accomodated with a series resistor. If unused, this
input may be left unconnected. For further informa-
tion, consult the related application note.
Margin Up:
When this input is asserted to
GND
, the
output voltage is increased by 5%. The input requires an
open-collector (open-drain) interface. It is not TTL
compatible. The percent change can be reduced with a
series resistor. If ununsed, this input may be left un-
connected. For further information, consult the related
application note.
Ordering Information
Input Voltage
ATH22T033 Series —3.3-V Input
22-A, 3.3-V Input Non-Isolated
Wide-Output Adjust Power Module
REVISION 00 (3DEC2003)
Output Voltage
Output Current
Model Number
2.95V to 3.65V
0.8V
1
to 2.5V
22A
ATH22T033-9(S)(J)
Options:
“-J”
“-SJ”
“-S”
-
-
-
Through-hole Termination, Tray Packaging
SMT Termination, Tray Packaging
SMT Termination, T&R Packaging
Notes:
1
Preset output voltage is 0.8V; externally adjustable to 2.5V through the Vo,Adjust pin