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PT7779
4 321
26
20-25
12
5
13-19
27
7-11
L
O
A
D
C
OUT
+
C
IN
+
PROGRAMMING PINS
V
IN
V
OUT
SYNC OUT
GND
REMOTE SENSE(+)
REMOTE SENSE(–)
STBY*
VID0
VID1
VID2
VID3
L1
1H
GND
VID4
6
Standard Application
Cin = Required 2400F electrolytic
Cout = Required 330F electrolytic
L1
= Optional 1H input choke
Description
The PT7779 is a high-output 32A
Integrated Switching Regulator (ISR),
housed in a 27-pin SIP package. The
PT7779 is the next generation of the
industry benchmark PT7771. The
PT7779 includes short circuit pro-
tection and requires only 330F of
output capacitance for proper oper-
ation.
The 32A output capability allows
the easy integration of the latest
high-speed, Ps, ASICs, DSPs into
existing 5V systems. For additional
current, the PT7779 is designed to
operate with up to two PT7741
32A compatible current boosters.
The output voltage is programmable
from 1.3V to 3.5V using a 5-bit input,
that is compatible with Intel’s Pentium
II Processors. A differential remote
sense compensates for any voltage
drop between the ISR and load.
For STBY* pin; open = output enabled;
ground = output disabled.
Pin-Out Information
Pin
Function
1 VID0
2 VID1
3 VID2
4 VID3
5 STBY*- Stand-by
6 VID4
7 Vin
8 Vin
9 Vin
10 Vin
11 Vin
12 Remote Sense Gnd (3)
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 Remote Sense Vout
27 Sync Out
SLTS116
(Revised 8/31/2000)
PT7779—5V
32 Amp Programmable Integrated
Switching Regulator
Specifications
Characteristics
PT7779
(T
a = 25°C unless noted)
Symbols
Conditions
Min
Typ
Max
Units
Output Current
Io
Ta = +60°C, 200 LFM, pkg N
0.1 (1)
—31
A
Ta = +25°C, natural convection
0.1 (1)
—32
Input Voltage Range
Vin
0.1A
≤ Io ≤ 32A
4.5
—
5.5
V
Output Voltage Tolerance
Vo
Vin = +5V, Io = 32A
Vo-0.03
—
Vo+0.03
V
–40°C
≤ Ta ≤ +85°C
Line Regulation
Regline
4.5V
≤ Vin ≤ 5.5V, Io = 32A
—
±10
—
mV
Load Regulation
Regload
Vin = +5V, 0.1 ≤ Io ≤ 32A
—
±10
—
mV
Vo Ripple/Noise pk-pk
Vn
Vin = +5V, Io = 32A
—
50
—
mV
Transient Response
ttr
Io step between 16A and 32A
—
100
—
Sec
with Cout = 330F
Vos
Vo over/undershoot
—
200
—
mV
Efficiency
η
Vin = +5V, Io = 20A, Vo = 3.3V
—
90
—
%
Switching Frequency
o
4.5V
≤ Vin ≤ 5.5V
300
350
400
kHz
0.1A
≤ Io ≤ 32A
Absolute Maximum
Ta
Over Vin Range
–40
—
+85 (2)
°C
Operating Temperature Range
Storage Temperature
Ts
—
-40
—
+125
°C
Mechanical Vibration
Per Mil-STD-883D, Method 2007.2,
—
10/15
—
G’s
20-20,000Hz, Soldered in a PC board
Weight
—
Vertical/Horizontal
—
53/66
—
grams
Notes:
(1) ISR-will operate down to no load with reduced specifications.
(2) Consult the Safe Operating Area curves, or contact the factory for the appropriate derating.
(3) If the remote sense ground is not used, pin 12 must be connected to pin13 for optimum output voltage accuracy.
External Capacitors: The PT7779 requires a minimum output capacitance of 330F for proper operation. The PT7779 also requires an input capacitance of 2400F,
which must be rated for a minimum of 2.0Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For further infor-
mation, see the accompanying application note on capacitor selection for this product.
Input Filter: An input filter inductor is optional for most applications. The input inductor must be sized to handle 32ADC with a typical value of 1H.