For assistance or to order, call
(800) 531-5782
PT7746
Series
32 AMP “CURRENT BOOSTER”
FOR PT7770 SERIES
Application Notes
Mechanical Outline
Product Selector Guide
Revised 8/13/98
The PT7746 is a new high-perfor-
mance 32 Amp “Current Booster” for
the PT7770 Series housed in a 27-pin
SIP package.
Multiple PT7746 boosters will
operate in parallel with the PT7770
boosting output current in incre-
ments of 32A. Combinations of
PT7770s and PT7746 current
boosters can easily supply enough
power for virtually any multiple
mega-processor application.
A PT7746 current booster adds a parallel
output stage driven by the PT7770. As such,
the system runs in perfect sychronization
providing a low noise solution.
The PT7746 only operates in
combination with the PT7770 series and is
not a stand-alone product. Therefore, please
refer to the PT7771, PT7772, or PT7777
series data sheet for performance
specifications. The PT7746 also has the
same mechanical dimensions and package
options as the PT7770 series.
Pin-Out Information
Pin Function
Pin Function
14
15
16
17
18
19
20
21
22
23
24
25
26
27
GND
GND
GND
GND
GND
GND
V
out
V
out
V
out
V
out
V
out
V
out
Do not connect
Master Sync In
Ordering Information
PT7746
t
(For dimensions and PC Board layout,
see Package Styles 1020 and 1030.)
Features
•
32A Current Boost
•
Automatically Tracks
Vo of PT7770
•
High Efficiency
•
Input Voltage Range:
3V to 5.5V
•
Synchronized with PT7770
•
27-pin SIP Package
•
Run up to 2 in Parallel -
96 Amps
1
2
3
4
5
6
7
8
9
10
11
12
13
Do not connect
Do not connect
Do not connect
Do not connect
Do not connect
Do not connect
V
in
V
in
V
in
V
in
V
in
Do not connect
GND
PT Series Suffix
(PT1234X)
Case/Pin
Configuration
Vertical Through-Hole
Horizontal Through-Hole
Horizontal Surface Mount
N
A
C
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
VID4
REMOTE SENSE (+)
6 4 3 2 1
26
V
IN
L1
7 - 11
1µH
+
27
PT7770
13 - 19
5
12
20 - 25
V
OUT
C
IN
STBY*
GND
C
OUT
+
LOAD
GND
REMOTE SENSE (-)
27
L1
7 - 11
1µH
+
PT7746
13 - 19
20 - 25
When
Cin
Cout
L1
+
used with PT7771/7772:
= Required 2400µF electrolytic
= Required 2400µF electrolytic
= Optional 1µH input choke
used with PT7777:
= Required 2400µF electrolytic
= Required 680µF electrolytic
= Optional 1µH input choke
C
IN
C
OUT
When
Cin
Cout
L1
Output Capacitors:
When used with a PT7771 or PT7772, the PT7746 requires a minimum ouput capacitance of 2400µF. When used with a PT7777,
the PT7746 requires a minimum ouput capacitance of 680µF for proper operation. Do not use Oscon type capacitors. The maximum allowable output
capacitance is 30,000µF.
Input Filter:
An input filter is optional for most applications. The input inductor must be sized to handle 32ADC with a typical value of 1µH. The input
capacitance must be rated for a minimum of 2.6Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required.
4
Power Trends, Inc.
27715 Diehl Road, Warrenville, IL 60555
(800) 531-5782
Fax: (630) 393-6902
http://www.powertrends.com
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©
1999, Texas Instruments Incorporated
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