PT7720 Datasheet, PDF (1/4 Pages) Texas Instruments – 17 AMP 12V INPUT “BIG-HAMMER II” PROGRAMMABLE ISR

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PT7720
Series
17 AMP 12V INPUT “BIG-HAMMER II” PRO-
GRAMMABLE ISR
Revised 1/13/99
Application Notes
Mechanical Outline
Product Selector Guide
The PT7720 series is a new +12V input,
17A output, high-performance Integrated
Switching Regulator (ISR) housed in a 27-
pin 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 I_out
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 re-
mote sense is also provided which
automatically compensates for any voltage
drop from the ISR to the load.
1200µF of output capacitance is re-
quired for proper operation.
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
VID4
V_IN
L1
1µH
6432 1
26
7 - 11 _PT7720
REMOTE SENSE (+)
20 - 25
V_OUT
SYNC OUT
GND
STBY*
+
C_IN
27 13 - 19 5 12
+
C_OUT
LOAD
GND
REMOTE SENSE (-)
Cin = Required 560µF electrolytic
(See input filter note)
Cout = Required 1200µF electrolytic
L1 = Optional 1µH input choke
Specifications
Pin-Out Information
Pin Function
1 VID0
2 VID1
3 VID2
4 VID3
5 STBY* - Stand-by
6 VID4
7 V_in
8 V_in
9 V_in
10 V_in
11 V_in
12 Remote Sense Gnd
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
For STBY* pin:
open = output enabled
ground = output disabled.
Features
• +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
Characteristics
(T_a = 25°C unless noted)
Symbols
Conditions
PT7720 SERIES
Min
Typ
Max
Units
Output Current
Output Power
Input Voltage Range
Output Voltage Tolerance
Line Regulation
Load Regulation
Vo Ripple/Noise
Io
Po
Vin
∆Vo
Regline
Reg_load
Vn
Ta = +60°C, 200 LFM, pkg N, Vo ≤ 5V
T_a = +25°C, natural convection, V_o ≤ 5V
Ta = +60°C, 200 LFM, pkg N, Vo ≥ 5V
T_a = +25°C, natural convection, V_o ≥ 5V
0.1A ≤ Io ≤ 17A
Vin = +12V, Io = 17A
0°C ≤ Ta ≤ +60°C
(PT7721)
(PT7722)
11V ≤ Vin ≤ 14V, Io = 17A (Using remote sense)
V_in = +12V, 0.1 ≤ I_o ≤ 17A (Using remote sense)
Vin = +12V, Io = 17A
(PT7721)
(PT7722)
0.1^*
0.1^*
—
—
11.0
Vo-0.03
—
—
—
—
—
—
—
—
—
—
—
±1.0%
±5
±5
50
100
17^**
17^**
85
85
14.0
Vo+0.03
±2.0%
±10
±10
—
—
A
A
Watts
Watts
V
V
% Vo
mV
mV
mVpp
mVpp
Transient Response
ttr
with C_out = 1200µF
V_os
Efficiency
η
Switching Frequency
ƒo
Io step between 7.5A and 15A
—
V_o over/undershoot
—
Vin = +12V, Io = 10A
Vo = 5.0V
—
V_o = 3.3V
—
Vo = 2.5V
—
Vo = 1.5V
—
11V ≤ Vin ≤ 14V
0.1A ≤ Io ≤ 17A
300
100
—
200
—
90
—
88
—
85
—
78
—
µSec
mV
%
%
%
%
350
400
kHz
Absolute Maximum
T_a
—
Operating Temperature Range
0
—
+85
°C
Recommended Operating
T_a
Temperature Range
Storage Temperature
T_s
Mechanical Shock
Forced Air Flow = 200 LFM
At Vin = 12V, Io = 12A
0
—
-40
Per Mil-STD-883D, Method 2002.3 , 1 msec,
Half Sine, mounted to a fixture
—
—
—
TBD
+65^***
°C
+125
°C
—
G’s
Mechanical Vibration
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, Soldered in a PC board
—
TBD
—
G’s
Weight
—
Vertical/Horizontal
—
51/64
—
grams
* 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 [phone] Fax: [phone] http://www.powertrends.com