For assistance or to order, call
(800) 531-5782
Revised 1/13/99
PT7720
Series
17 AMP 12V INPUT “BIG-HAMMER II” PROGRAMMABLE ISR
The PT7720 series is a new +12V input,
17A output, high-performance Integrated
Switching Regulator (ISR) housed in a 27pin SIP package. The 17A capability allows
easy integration of the latest high-speed,
low-voltage µPs and bus drivers into +12V
distributed power systems.
The PT7720 series has been designed
to work in parallel with one or more of the
PT7748 current boosters for increased Iout
in increments of 17A.
The output voltage of the PT7721 can
be easily programmed from 1.3V to 3.5V
with a 5 bit input compatible with Intel’s
Pentium® IIProcessor. A differential remote sense is also provided which
automatically compensates for any voltage
drop from the ISR to the load.
1200µF of output capacitance is required for proper operation.
Pin-Out Information
Features
Pin Function
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
VID4
VIN
REMOTE SENSE (+)
6 4 3 2 1
L1
PT7720
7 - 11
1µH
CIN
+
26
27
13 - 19
5
VOUT
20 - 25
12
COUT
+
LOAD
SYNC OUT
GND
GND
STBY*
REMOTE SENSE (-)
Cin
= Required 560µF electrolytic
(See input filter note)
C out = Required 1200µF electrolytic
L1 = Optional 1µH input choke
Application Notes
Mechanical Outline
Product Selector Guide
Pin Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
VID0
VID1
VID2
VID3
STBY* - Stand-by
VID4
Vin
Vin
Vin
Vin
Vin
Remote Sense Gnd
GND
GND
• +12V bus input
• 5-bit Programmable:
1.3V to 3.5V or
4.5V to 7.6V
• High Efficiency
• Differential Remote Sense
• 27-pin SIP Package
• Parallelable with PT7748
17A current boosters
GND
GND
GND
GND
GND
Vout
Vout
Vout
Vout
Vout
Vout
Remote Sense Vout
Sync Out
For STBY* pin:
open = output enabled
ground = output disabled.
Specifications
PT7720 SERIES
Characteristics
(Ta = 25°C unless noted)
Symbols
Conditions
Min
Typ
Max
Units
Output Current
Io
Ta = +60°C, 200 LFM, pkg N, Vo ≤ 5V
Ta = +25°C, natural convection, Vo ≤ 5V
0.1 *
0.1 *
—
—
17**
17**
A
A
Output Power
Po
Ta = +60°C, 200 LFM, pkg N, Vo ≥ 5V
Ta = +25°C, natural convection, Vo ≥ 5V
—
—
—
—
85
85
Watts
Watts
11.0
—
14.0
V
Vo-0.03
—
—
±1.0%
Vo+0.03
±2.0%
V
% Vo
mV
Input Voltage Range
Vin
0.1A ≤ Io ≤ 17A
Output Voltage Tolerance
∆Vo
Vin = +12V, Io = 17A
0°C ≤ Ta ≤ +60°C
Line Regulation
Regline
11V ≤ Vin ≤ 14V, Io = 17A (Using remote sense)
—
±5
±10
Load Regulation
Regload
Vin = +12V, 0.1 ≤ Io ≤ 17A (Using remote sense)
—
±5
±10
mV
Vo Ripple/Noise
Vn
Vin = +12V, Io = 17A
—
—
50
100
—
—
mVpp
mVpp
Transient Response
with Cout = 1200µF
t tr
Vos
Io step between 7.5A and 15A
Vo over/undershoot
—
—
100
200
—
—
µSec
mV
Efficiency
η
Vin = +12V, Io = 10A
—
—
—
—
90
88
85
78
—
—
—
—
%
%
%
%
Switching Frequency
ƒo
11V ≤ Vin ≤ 14V
0.1A ≤ Io ≤ 17A
300
350
400
kHz
Absolute Maximum
Operating Temperature Range
Ta
—
0
—
+85
°C
Recommended Operating
Temperature Range
Ta
Forced Air Flow = 200 LFM
At Vin = 12V, Io = 12A
0
—
+65***
°C
Storage Temperature
Ts
—
-40
—
+125
°C
Mechanical Shock
Per Mil-STD-883D, Method 2002.3 , 1 msec,
Half Sine, mounted to a fixture
—
TBD
—
G’s
Mechanical Vibration
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, Soldered in a PC board
Vertical/Horizontal
—
TBD
—
G’s
—
51/64
—
grams
Weight
—
(PT7721)
(PT7722)
(PT7721)
(PT7722)
Vo
Vo
Vo
Vo
= 5.0V
= 3.3V
= 2.5V
= 1.5V
* ISR-will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.
** The PT7720 series can be easily paralleled with one or more of the PT7748 Current Boosters to provide increased output current in increments of 17A.
*** See Safe Operating Area chart.
Output Capacitors: The PT7720 series requires a minimum output capacitance of 1200µF for proper operation. Do not use Oscon type capacitors. The maximum allowable output capacitance
Is (57,000 ÷ Vout)µF, or 15,000µF, whichever is less.
Input Filter: An input inductor is optional for most applications. The input inductor must be sized to handle 7ADC with a typical value of 1µH. The input capacitance must be rated for a
minimum of 4.0 Arms of ripple current when operated at maximum output current and maximum output voltage. Contact an applications engineer for input capacitor selection for applications
at other output voltages and output currents.
50
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 (800) 531-5782 Fax: (630) 393-6902 http://www.powertrends.com
