PT7681 Datasheet, PDF (2/12 Pages) Texas Instruments – 30-A Programmable ISR With Margin Up/Down Controls

PT7681—5V
30-A Programmable ISR
With Margin Up/Down Controls
Pin-Out Information
Pin Function
1 VID0
2 VID1
3 VID2
4 VID3
5 STBY *
6 MARGDN
7 Vin
8 Vin
9 Vin
10 Vin
11 Vin
12 Sense(–)
13 GND
14 GND
Pin Function
15 GND
16 GND
17 GND
18 GND
19 GND
20 Vout
21 Vout
22 Vout
23 Vout
24 Vout
25 Vout
26 Sense(+)
27 MARGUP
* For STBY pin: open =output enabled
ground =output disabled.
SLTS177B - DECEMBER 2002 - REVISED JULY 2006
Programming Information
VID3 VID2 VID1 VID0
1111
1110
1101
1100
1011
1010
1001
1000
0111
0110
0101
0100
0011
0010
0001
0000
Vout
2.00V
2.10V
2.20V
2.30V
2.40V
2.50V
2.60V
2.70V
2.80V
2.90V
3.00V
3.10V
3.20V
3.30V
3.40V
3.50V
Logic 0 = Pin 12 potential (Rem Sense Gnd)
Logic 1 = Open circuit (no pull-up resistors)
VID 3 must not be changed while the unit is operating.
Pin Descriptions
Vin: The positive input voltage power node to the mod-
ule, which is referenced to common GND.
GND: This is the common ground connection for the
‘V_in’ and ‘V_out’ power connections. It is also the 0VDC
reference for the ‘STBY’ control input.
STBY: The STBY pin is an open-collector/drain nega-
tive logic input that is referenced to GND. Applying a
ground signal to this input will disable the module’s
output and place the regulator in “standby” mode.
When in standby, the input current drawn by the regula-
tor is significantly reduced. If the STBY input is left
open circuit, the module will produce an output when-
ever a valid input source is applied.
VID0–VID3: Selects the set-point output voltage of the
regulator according to the applicable program code (See
programming information). Each input, VID0 through
VID3, must either be connected to ‘Sense(–)’ or left open
circuit.
Vout: The regulated positive power output with respect
to the GND node. The set point voltage at this node is
defined by the status of the pins VID0 through VID3.
Sense(+): Provides the regulator with the capability to
regulate the set-point voltage at the load. When used
with ‘Sense(–)’, the regulation circuitry will compensate
for voltage drop between the converter and the load.
This pin may be left open circuit, but connecting it to
‘Vout’ will improve load regulation.
Sense(–): This is the logic ‘0’ reference for the inputs
VID0 through VID3. It also provides the regulator with a
differential remote sense capability when used with the
‘Sense(+)’ input. For optimum output voltage accuracy
this pin should always be connected to GND.
MARGDN: This is an open-collector/drain negative logic
input. Applying a ground signal to this input increases
the output voltage of the module by up to 5%. The con-
trol provides a convenient method for testing the operation
of the load circuit over its supply voltage tolerance mar-
gins.
MARGUP: An open-collector/drain negative logic input
that operates similar to the MARGDN control. Applying
a ground signal to this input automatically decreases the
output by up to 5%.
For technical support and more information, see inside back cover or visit www.ti.com