PT7708—3.3V
20 Amp Programmable
Next Generation “Big Hammer”
SLTS083
(Revised 6/30/2000)
Description
The PT7708 niesxt a generation
“Big Hammer”,higha-performance
Integrated Switching Regulator (ISR),
mable from 1.3V 2.0to5V with
which is made available in Power
voltage µPs, and bus drivers.
The PT770o8utput is program-
a
4-bit input, which is compatible with
the Intel Pentium Processor. A differ-
ential remote sense is also provided to
Trends’ aluminum 27-pin SIP acpk-
age.
The PT7708 improves on the
popular PT7706 with 20A of output
current and short circuit protection.
the ISR and load.
The PT7708 is suitable for exist-
ing 5V system designresquirtehat
power fothre latest high-speed, low-
compensate for voltage drop between
Only 330µF of output capacitance
are required for proper operation.
Pin-Out Information
Pin Function
Pin Function
Standard Application
Pin Function
10 Vin
11 Vin
12 Remote Sense Gnd
13 GND
14GND
1
2
3
VID0
VID1
VID2
19 GND
20 Vout
21 Vout
22 Vout
23 Vout
PROGRAMMING PINS
REMOTE SENSE (+)
VID0
VID1
VID2
VID3
(4)
4
3
2
VID0
1
26
4VID3
SNS(+)
VID3
-
VO U T
L1
5
6
7
8
9
STBY* - Stand-by
7-11
20-25
Vo
Vin
VIN
PT7708
1
H
Do Not Connect
24V
out
Synch
15 GND
16 GND
17 GND
18 GND
STBY
5
G N D
13-19
SNS(-)
12
Out
+
+
LOAD
27
Vin
Vin
Vin
25 Vout
CIN
CO U T
SYNC OUT
G N D
26 Remote Sense
V
out
G N D
)
27 Sync Out
REMOTE SENSE
(
STBY*
For STBY* pin:
open = output enabled
ground = output disabled.
C
C
= Required 1500µF electrolytic
= Required 330µF electrolytic
in
out
L1 = Optional 1µH input choke
Specifications
PT7708 SERIES
Typ
Characteristics
(Ta = 25°C unless noted)
Symbols
Conditions
Min
Max
Units
(1)
0.1(1)
Output Current
Io
Ta = +60°C, 200 LFM, pkg N
Ta = +25°C, natural convection
0.1
—
—
19
20
A
V
V
Input Voltage Range
Vin
0.1A ≤ Io ≤ 20A
3.1
—
3.6
Output Voltage Tolerance
∆Vo
Vin = +3.3V, Io = 20A
Vo-0.03
—
Vo+0.03
0°C ≤ Ta ≤ +65°C
Line Regulation
Load Regulation
Vo Ripple/Noise
Regline
Regload
Vn
3.1V ≤ Vin ≤ 3.6V, Io = 20A
Vin = +3.3V, 0.1 ≤ Io ≤ 20A
Vin = +3.3V, Io = 20A
—
—
—
10
10
—
—
—
mV
mV
mV
50
Transient Response
with Cout = 330µF
ttr
Io step between 10A and 20A
Vo over/undershoot
—
—
50
—
—
µSec
mV
Vos
100
Efficiency
η
Vin = +3.3V, Io = 10A
Vo = 1.8V
Vo = 1.5V
—
—
85
82
—
—
%
%
Vin = +3.3V, Io = 20A
Vo = 1.8V
—
78
—
Vo
=
1.5V
—
74—
Switching
Frequency
ƒ
3.1V ≤ Vin ≤ 3.6V
0.1A ≤ Io ≤ 20A
o
300
350
—
400
kHz
°C
(2)
(3)
Absolute Maximum
Ta
Over Vin and Io Ranges
–40
+85
Operating Temperature Range
Storage Temperature
Mechanical Shock
Ts
—
–40
—
+125
°C
Per Mil-STD-883D, Method 2002.3
1 msec, Half Sine, mounted to a fixture
—
—
—
500
10
—
—
—
G’s
Mechanical Vibration
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, Soldered in a PC board
G’s
Weight
—
Vertical/Horizontal
31/41
grams
Notes: (1) ISR-will operate down to no load with reduced specifications.
(2) For operation below 0°C, Cin and Cout must have stable characteristics. Use either low ESR tantalum or Oscon® capacitors.
(3) See Safe Operating Area curves or contact the factory for the appropriate derating.
(4) If the Remote Sense Ground is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy.
External Capacitors: The PT7708 requires a minimum output capacitance of 330µF for proper operation. The PT7708 also requires an input capacitance of 1500µF,
which must be rated for a minimum of 1.4Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For more
information refer to the application note regarding capacitor selection for this product.
Input Filter: An input filter inductor is optional for most applications. The inductor must be sized to handle 20ADC with a typical value of 1µH.
For technical support and more information, see inside back cover or visit www.ti.com/powertrends