PT7778 Datasheet, PDF (1/3 Pages) Texas Instruments – 32 Amp Programmable Integrated Switching Regulator

PT7778—3.3V
32 Amp Programmable Integrated
Switching Regulator
Description
The PT7778 is a high-output 32A
Integrated Switching Regulator (ISR),
housed in a 27-pin SIP package, The
PT7778 is the 3.3V-input bus version
of the PT7779. It includes short
circuit protection and requires only
330µF of output capacitance for
proper operation.
The output voltage of the PT7778
is programmable from 1.3V to 2.05V
using a 4-bit input, which is compati-
SLTS115
(Revised 8/31/2000)
ble with Intel’s Pentium^®II Processors.
The 32A capability provides the
ideal power source for the industry’s
latest high-speed, low-voltage µPs,
DSPs, and custom VLSI devices.
For additional current, the PT7778
may be paralleled with up to two
PT7740 32A current boosters.
A differential remote sense is
provided to compensate for voltage
drop between the ISR and load.
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
L1
V _IN
1µH
SYNC OUT ^{C IN}
REMOTE SENSE (+)
4321
VID3 - VID0
26
SNS(+)
7-11 _Vin
PT7778
Vo ^20-25
Synch
+
STBY Out
GND
SNS(-)
+
5 27 13-19 12
C_OUT
V_OUT
LOAD
GND
GND
STBY*
REMOTE SENSE (–)
Specifications
Cin = Required 2400µF electrolytic
Cout = Required 330µF electrolytic
L1 = Optional 1µH input choke
Pin-Out Information
Pin Function
Pin Function
1 VID0
2 VID1
15 GND
16 GND
3 VID2
17 GND
4 VID3
5 STBY*- Stand-by
6 N/C
7 Vin
8 Vin
9 Vin
10 Vin
11 Vin
12 Remote Sense Gnd (3)
13 GND
18 GND
19 GND
20 Vout
21 Vout
22 Vout
23 Vout
24 Vout
25 Vout
26 Remote Sense Vout
27 Sync Out
14 GND
For STBY* pin; open = output enabled;
ground = output disabled.
Characteristics
(T _a = 25°C unless noted)
Output Current
Input Voltage Range
Output Voltage Tolerance
Line Regulation
Load Regulation
Vo Ripple/Noise pk-pk
Transient Response
with Cout = 330µF
Efficiency
Switching Frequency
Absolute Maximum
Operating Temperature Range
Storage Temperature
Mechanical Vibration
Weight
Symbols
I_o
V_in
∆Vo
Regline
Regload
Vn
ttr
Vos
η
ƒo
Ta
Ts
—
Conditions
T_a = +60°C, 200 LFM, pkg N
Ta = +25°C, natural convection
0.1A ≤ I_o ≤ 32A
Vin = +3.3V, Io = 32A
–40°C ≤ T_a ≤ +85°C
3.1V ≤ Vin ≤ 3.6V, Io = 32A
Vin = +3.3V, 0.1 ≤ Io ≤ 32A
Vin = +3.3V, Io = 32A
Io step between 16A and 32A
Vo over/undershoot
Vin = +3.3V, Io = 20A, Vo = 1.8V
3.1V ≤ Vin ≤ 3.6V
0.1A ≤ Io ≤ 32A
Over Vin Range
—
Per Mil-STD-883D, Method 2007.2
20-20,000Hz, Soldered in a PC board
Vertical/Horizontal
Min
0.1 (1)
0.1 ⁽¹⁾
3.1
PT7778
Typ
—
—
—
Vo-0.03 —
—
±10
—
±10
—
50
—
100
—
200
—
90
300
350
–40
—
-40
—
—
10/15
—
53/66
Max
32
31
3.6
Vo+0.03
—
—
—
—
—
—
400
Units
A
V
V
mV
mV
mV
µSec
mV
%
kHz
+85 ⁽²⁾
+125
—
—
°C
°C
G’s
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 PT7778 requires a minimum output capacitance of 330µF for proper operation. The PT7778 also requires an input capacitance of 2400µF,
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 1µH.
For technical support and more information, see inside back cover or visit www.ti.com/powertrends