Texas Instruments PT7777C Datasheet

Series

Standard Application

Cin= Required 2400µF electrolytic
C

out

= Required 680µF electrolytic

L1 = Optional 1µH input choke

32 AMP HIGH-PERFORMANCE
“SLEDGE HAMMER” PROGRAMMABLE ISR

PT7777

The PT7777 is a new series of
high-performance, 32 Amp Inte­grated Switching Regulators (ISRs)
housed in a 27-pin SIP package.
The 32A capability allows easy
integration of the latest high-speed,
low-voltage µPs, ASICs, DSPs, and
bus drivers into existing 5V systems.

The output voltage of the PT7777

can be easily programmed from 1.3V
to 3.5V with a 5 bit input compatible
with Intel’s Pentium



Pro Processor. A
differential remote sense is also pro­vided which automatically compensates
for any voltage drop from the ISR
to the load.

680µF of output capacitance

is required for proper operation.

For STBY* pin; open = output enabled;
ground = output disabled.

Pin-Out Information

PT7777

7 - 11

13 - 19

20 - 25

27

V

IN

GND

1µH

GND

V

OUT

C

OUT

+

C

IN

+

12

261

L1

SYNC OUT

LOAD

REMOTE SENSE (+)

REMOTE SENSE (-)

VID1
VID2
VID3
VID4

PROGRAMMING PINS

234

STBY*

5

6

VID0

For assistance or to order, call [phone]

Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com

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

Pin Function

14 GND
15 GND
16 GND
17 GND

18 GND
19 GND
20 V

out

21 V

out

22 V

out

23 V

out

24 V

out

25 V

out

26 Remote Sense V

out

27 Sync Out

Specifications

Characteristics

PT7777 SERIES

(T a = 25°C unless noted) Symbols Conditions Min Typ Max Units

Output Current I

o

Ta = +60°C, 200 LFM, pkg N 0.1

(1)

—32A

Ta = +25°C, natural convection 0.1

(1)

—26A

Input Voltage Range V

in

0.1A ≤ I

o

≤ 32A 4.5

(2)

— 5.5 V

Output Voltage Tolerance ∆V

o

V

in

= +5V, Io = 32A

V

o-0.03 — Vo+0.03 V

0°C ≤ Ta ≤ +55°C

Line Regulation Reg

line

4.5V ≤ V

in

≤ 5.5V, I

o

= 32A — ±10 — mV

Load Regulation Reg

load

Vin = +5V, 0.1 ≤ I

o

≤ 32A — ±10 — mV

Vo Ripple/Noise pk-pk V

n

V

in

= +5V, Io = 32A — 50 — mV

Transient Response t

tr

Io step between 16A and 32A — 100 — µSec

with C

out

= 680µF V

os

Vo over/undershoot — 200 — mV

Efficiency η V

in

= +5V, Io = 20A, Vo = 3.3V — 90 — %

Switching Frequency ƒ

o

4.5V ≤ V

in

≤ 5.5V

650 700 750 kHz

0.1A ≤ I

o

≤ 32A

Absolute Maximum T

a

— 0 — +85 °C

Operating Temperature Range
Recommended Operating T

a

Forced Air Flow = 200 LFM

0 — +65 °C

Temperature Range Over V

in and Io

Ranges

Storage Temperature T

s

— -40 — +125 °C

Weight — Vertical/Horizontal — 53/66 — grams

(1) ISR-will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.
(2) The minimum input voltage is 4.5V or V

out

+1.2V, whichever is greater.

Output Capacitors:

The PT7777 series requires a minimum output 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.

Revised 7/31/98

Ordering Information

PT7777

❏❏

❏❏

❏ = 1.3 to 3.5 Volts

Programming Information

VID4=1 VID4=0

VID3 VID2 VID1 VID0 Vout Vout

1 1 1 1 2.0V 1.30V
1 1 1 0 2.1V 1.35V
1 1 0 1 2.2V 1.40V
1 1 0 0 2.3V 1.45V
1 0 1 1 2.4V 1.50V
1 0 1 0 2.5V 1.55V
1 0 0 1 2.6V 1.60V
1 0 0 0 2.7V 1.65V
0 1 1 1 2.8V 1.70V
0 1 1 0 2.9V 1.75V
0 1 0 1 3.0V 1.80V
0 1 0 0 3.1V 1.85V
0 0 1 1 3.2V 1.90V
0 0 1 0 3.3V 1.95V
0 0 0 1 3.4V 2.00V
0 0 0 0 3.5V 2.05V

Logic 0 = Pin 12 potential (remote sense gnd)
Logic 1 = Open circuit (no pull-up resistors)
VID3 and VID4 may not be changed while the unit
is operating.

For dimensions and PC board layout,
see Package Style 1020 and 1030

• +5V input

• 5-bit Programmable:

1.3V to 3.5V@32A

• High Efficiency

• Input Voltage Range:

4.5V to 5.5V

• Differential Remote

Sense

• 27-pin SIP Package

Features

Efficiency vs Output Current (@Vout=+3.3V)

Efficiency (%)Efficiency (%)

Efficiency (%)Efficiency (%)

Efficiency (%)

Output Current (A)Output Current (A)

Output Current (A)Output Current (A)

Output Current (A)

Safe Operating Area (@Vin=+5V, Vout=+3.3V, Pkg N)

Output Current (A)Output Current (A)

Output Current (A)Output Current (A)

Output Current (A)

Ambient TAmbient T

Ambient TAmbient T

Ambient T

emperaturemperatur

emperaturemperatur

emperatur

e (°C)e (°C)

e (°C)e (°C)

e (°C)

Airflow

Recommended Maximum

Operating Temperature

Note: SOA curves represent operating conditions at
which internal components are at or below manufacturer’s
maximum rated operating temperatures.

Power Dissipation vs Output Current (@Vout=+3.3V)

Pd (WPd (W

Pd (WPd (W

Pd (W

atts)atts)

atts)atts)

atts)

Output Current (A)Output Current (A)

Output Current (A)Output Current (A)

Output Current (A)

Output Ripple vs Output Current (@Vout=+3.3V)

Ripple (mVpp)Ripple (mVpp)

Ripple (mVpp)Ripple (mVpp)

Ripple (mVpp)

Output Current (A)Output Current (A)

Output Current (A)Output Current (A)

Output Current (A)

Vin

Vin

Vin

For assistance or to order, call [phone]

Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com

CHARACTERISTIC DATA

Series

PT7777

PT Series Suffix

(PT1234X)

Case/Pin
Configuration

Vertical Through-Hole N
Horizontal Through-Hole A
Horizontal Surface Mount C

60

70

80

90

100

0 4 8 12 16 20 24 28 32

4.5V

5.0V

5.5V

0

2

4

6

8

10

12

14

16

18

20

0 4 8 121620242832

4.5V

5.0V

5.5V

0

5

10

15

20

25

30

35

40

0 4 8 12 16 20 24 28 32

4.5V

5.0V

5.5V

20

30

40

50

60

70

80

90

0 4 8 12 16 20 24 28 32

Nat. Conv
60 LFM
120 LFM
200 LFM