PT7705 Datasheet, PDF (1/4 Pages) Texas Instruments – 18 AMP “BIG-HAMMER” PROGRAMMABLE INTEGRATED SWITCHING REGULATOR

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PT7705 Series
18 AMP “BIG-HAMMER” PROGRAMMABLE
INTEGRATED SWITCHING REGULATOR
Application Notes
Mechanical Outline
Product Selector Guide
Revised 5/15/98
The PT7705 is a new series of
high-performance, 18 Amp Integrated
Switching Regulators (ISRs) housed in
a 27-pin SIP package. The 18A capa-
bility allows easy integration of the
latest high-speed, low-voltage µPs and
bus drivers into existing 5V systems.
The PT7705 series has been de-
signed to work in parallel with one or
more of the PT7749 - 18A current
boosters for increased I_out in incre-
ments of 18A.
The output voltage of the PT7705
can be easily programmed from 1.3V
to 3.5V with a 5 bit input compatible
with Intel’s Pentium^® II Processor.
A differential remote sense is also pro-
vided which automatically compensates
for any voltage drop from the ISR to
the load.
1200µF of output capacitance are
required for proper operation.
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
VID4
V_IN
L1
1µH
SYNC OUT
GND
STBY*
+
C_IN
6432 1
REMOTE SENSE (+)
26
PT7705 ^{7 - 11}
20 - 25
V_OUT
27 13 - 19 5 12
+
C_OUT
LOAD
GND
REMOTE SENSE (-)
Cin = Required 1200µF electrolytic
Cout= Required 1200µF electrolytic
L1 = Optional 1µH input choke
Pin-Out Information
Pin Function
1 VID0
2 VID1
3 VID2
4 VID3
5 STBY* - Stand-by
6 VID4
7 V_in
8 Vin
9 V_in
Pin Function
10 V_in
11 Vin
12 Remote Sense Gnd
13 GND
14 GND
15 GND
16 GND
17 GND
18 GND
Pin Function
19 GND
20 Vout
21 V_out
22 Vout
23 V_out
24 Vout
25 V_out
26 Remote Sense Vout
27 Sync Out
For STBY* pin; open = output enabled; ground = output
disabled.
Specifications
Characteristics
(T_a = 25°C unless noted)
Symbols
Conditions
PT7705 SERIES
Min
Typ
Max
Units
Output Current
Input Voltage Range
Output Voltage Tolerance
Line Regulation
Load Regulation
V_o Ripple/Noise
Transient Response
with C_out = 1200µF
Efficiency
I_o
V_in
∆Vo
Regline
Regload
V_n
ttr
V_os
η
Switching Frequency
ƒo
Absolute Maximum
Ta
Operating Temperature Range
T_a = +60°C, 200 LFM, pkg N
Ta = +25°C, natural convection
0.1A ≤ I_o ≤ 15A
Vin = +5V, Io = 15A
0°C ≤ T_a ≤ +65°C
4.5V ≤ Vin ≤ 5.5V, Io = 15A
Vin = +5V, 0.1 ≤ Io ≤ 15A
V_in = +5V, I_o = 15A
Io step between 7.5A and 15A
V_o over/undershoot
Vin = +5V, Io = 10A
4.5V ≤ Vin ≤ 5.5V
0.1A ≤ I_o ≤ 15A
—
Vo = 3.3V
V_o = 2.9V
Vo = 2.5V
Vo = 1.8V
V_o = 1.5V
0.1^*
—
0.1^*
—
4.5^***
—
Vo-0.03 —
—
±10
—
±10
—
50
—
100
—
200
—
89
—
87
—
85
—
79
—
77
650
700
0
—
18^**
15^**
5.5
Vo+0.03
—
—
—
—
—
—
—
—
—
—
750
+85
A
A
V
V
mV
mV
mV
µSec
mV
%
%
%
%
%
kHz
°C
Recommended Operating
Ta
Temperature Range
Storage Temperature
Ts
Mechanical Shock
Forced Air Flow = 200 LFM
Over V_{in and} I_o Ranges
—
Per Mil-STD-883D, Method 2002.3
1 msec, Half Sine, mounted to a fixture
0
—
-40
—
+65**** °C
+125
°C
—
500
—
G’s
Mechanical Vibration
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, Soldered in a PC board
—
10
—
G’s
Weight
—
Vertical/Horizontal
—
31/41
—
grams
* ISR-will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.
**The PT7705 series can be easily paralleled with one or more of the PT7749 Current Boosters to provide increased output current in increments of 18A.
*** The minimum input voltage is 4.5V or V_out+1.2V, whichever is greater. ****See SOA curves.
Output Capacitors: The PT7705 series requires a minimum ouput capacitance of 1200µF for proper operation. Do not use Oscon type capacitors. The maximum
allowable output capacitance is 15,000µF. See Capacitor Application Note.
Input Filter: An input filter is optional for most applications. The input inductor must be sized to handle 15ADC with a typical value of 1µH. The input capacitance must be
rated for a minimum of 1.3Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required.
38
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