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SLTS211F – MAY 2003 – REVISED FEBRUARY 2007
DEVICE INFORMATION
TERMINAL FUNCTIONS
TERMINAL
NAME
GND
V
I
NO.
1,3,7,10
2
DESCRIPTION
This is the common ground connection for the
V
I
and
V
O
power connections. It is also the 0 Vdc
reference for the control inputs.
The positive input voltage power node to the module, which is referenced to common GND.
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 regulator is significantly reduced. If
the
Inhibit
pin is left open-circuit, the module produces an output whenever a valid input source is
applied.
A 1% resistor must be directly connected between this pin and pin 7 (GND) to set the output voltage to
a value higher than 0.8 V. The temperature stability of the resistor should be 100 ppm/°C (or better).
The set point range for the output voltage is from 1.2 V to 5.5 V for W-suffix devices, and 0.8 V to 1.8
V for L-suffix devices. The resistor value required for a given output voltage may be calculated using a
formula. If left open circuit, the module output voltage defaults to its lowest value. For further
information on output voltage adjustment, see the related application information section.
gives
the preferred resistor values for a number of standard output voltages.
The sense input allows the regulation circuit to compensate for voltage drop between the module and
the load. For optimal voltage accuracy,
V
O
Sense
should be connected to
Vout.
It can also be left
disconnected.
The regulated positive power output with respect to the
GND
node.
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 powered from the same input bus. If unused, this input should be
connected to V
I
.
Note: Due to the undervoltage lockout feature, the output of the module cannot follow
its own input voltage during power up. For more information, see the related application information
section.
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. For further information, see the related application
information section.
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. For further information, see the related application information section.
Inhibit
(1)
4
V
O
Adjust
5
V
O
Sense
V
O
6
8,9
Track
11
Margin
Down
(1)
12
Margin Up
(1)
(1)
13
Denotes negative logic:
Open = Normal operation
Ground = Function active
13 12 11
1
10
2
PTHXX030
(Top View)
9
8
7
3
4
5
6
5
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