Texas Instruments PT7721A, PT7721C, PT7721N, PT7722A, PT7722C Datasheet

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P T 7 7 2 0 S e r i e s

Revised 1/13/99

17 AMP 12V INPUT “BIG-HAMMER II” PRO-

Application Notes

GRAMMABLE ISR

Mechanical Outline

Product Selector Guide

The PT7720 series is a new +12V input, 17A output, high-performance Integrated Switching Regulator (ISR) housed in a 27pin SIP package. The 17A capability allows easy integration of the latest high-speed, low-voltage µPs and bus drivers into +12V distributedpowersystems.

The PT7720 series has been designed to work in parallel with one or more of the PT7748 current boosters for increased Iout

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 PentiumâIIProcessor. A differential remote sense is also provided which automaticallycompensatesforanyvoltage drop from the ISR to the load.

1200µF of output capacitance is required for proper operation.

Pin-Out Information

Features

Pin

Function

Pin

Function

• +12V bus input

Standard Application

1

VID0

15

GND

• 5-bit Programmable:

2

VID1

16

GND

1.3V to 3.5V or

3

VID2

17

GND

VID0

4.5V to 7.6V

4

VID3

PROGRAMMING PINS

18

GND

VID1

REMOTE SENSE (+)

5

• High Efficiency

VID2

6 4 3 2 1

26

STBY* - Stand-by

19

GND

VID4

VID3

VIN

L1

PT7720

VOUT

6

VID4

20

Vout

• Differential Remote Sense

7 - 11

20 - 25

7

Vin

1µH

21

Vout

• 27-pin SIP Package

8

Vin

CIN

+

27

13 - 19 5

12

+

22

Vout

• Parallelable with PT7748

COUT

LOAD

9

Vin

23

Vout

SYNC OUT

17A current boosters

GND

GND

10

Vin

24

Vout

STBY*

REMOTE SENSE (-)

11

Vin

25

Vout

Cin

= Required 560µF electrolytic

12

Remote Sense Gnd

26

Remote Sense Vout

(See input filter note)

13

GND

27

Sync Out

Cout = Required 1200µF electrolytic

14

GND

For STBY* pin:

L1 = Optional 1µH input choke

Specifications

open = output enabled

ground = output disabled.

Characteristics							PT7720 SERIES
(Ta = 25°C unless noted)	Symbols	Conditions					Min	Typ	Max	Units
Output Current	Io	Ta = +60°C, 200 LFM, pkg N, Vo			£ 5V		0.1*	—	17**	A
		Ta = +25°C, natural convection, Vo			£ 5V		0.1*	—	17**	A
Output Power	Po	Ta = +60°C, 200 LFM, pkg N, Vo			³ 5V		—	—	85	Watts
		Ta = +25°C, natural convection, Vo			³ 5V		—	—	85	Watts
Input Voltage Range	Vin	0.1A £ Io £ 17A					11.0	—	14.0	V
Output Voltage Tolerance	DVo	Vin	= +12V, Io = 17A	(PT7721)			Vo-0.03	—	Vo+0.03	V
		0°C	£ Ta £ +60°C	(PT7722)			—	±1.0%	±2.0%	% Vo
Line Regulation	Regline	11V £ Vin £ 14V, Io = 17A (Using remote sense)					—	±5	±10	mV
Load Regulation	Regload	Vin = +12V, 0.1 £ Io £ 17A (Using remote sense)					—	±5	±10	mV
Vo Ripple/Noise	Vn	Vin = +12V, Io = 17A		(PT7721)			—	50	—	mVpp
				(PT7722)			—	100	—	mVpp
Transient Response	ttr	Io step between 7.5A and 15A					—	100	—	µSec
with Cout = 1200µF	Vos	Vo over/undershoot					—	200	—	mV
Efficiency	h	Vin = +12V, Io = 10A		Vo = 5.0V			—	90	—	%
				Vo = 3.3V			—	88	—	%
				Vo = 2.5V			—	85	—	%
				Vo = 1.5V			—	78	—	%
Switching Frequency	ƒo	11V £ Vin £ 14V					300	350	400	kHz
		0.1A £ Io £ 17A
Absolute Maximum	Ta	—					0	—	+85	°C
Operating Temperature Range
Recommended Operating	Ta	Forced Air Flow = 200 LFM					0	—	+65***	°C
Temperature Range		At Vin = 12V, Io = 12A
Storage Temperature	Ts	—					-40	—	+125	°C
Mechanical Shock		Per Mil-STD-883D, Method 2002.3 , 1 msec,					—	TBD	—	G’s
		Half Sine, mounted to a fixture
Mechanical Vibration		Per Mil-STD-883D, Method 2007.2,					—	TBD	—	G’s
		20-2000 Hz, Soldered in a PC board
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

Programming Information

				PT7721		PT7722
				VID4=1 VID4=0		VID4=1 VID4=0
VID3	VID2	VID1	VID0	Vout	Vout	Vout	Vout
1	1	1	1	2.0V	1.30V	4.5V	6.1V
1	1	1	0	2.1V	1.35V	4.6V	6.2V
1	1	0	1	2.2V	1.40V	4.7V	6.3V
1	1	0	0	2.3V	1.45V	4.8V	6.4V
1	0	1	1	2.4V	1.50V	4.9V	6.5V
1	0	1	0	2.5V	1.55V	5.0V	6.6V
1	0	0	1	2.6V	1.60V	5.1V	6.7V
1	0	0	0	2.7V	1.65V	5.2V	6.8V
0	1	1	1	2.8V	1.70V	5.3V	6.9V
0	1	1	0	2.9V	1.75V	5.4V	7.0V
0	1	0	1	3.0V	1.80V	5.5V	7.1V
0	1	0	0	3.1V	1.85V	5.6V	7.2V
0	0	1	1	3.2V	1.90V	5.7V	7.3V
0	0	1	0	3.3V	1.95V	5.8V	7.4V
0	0	0	1	3.4V	2.00V	5.9V	7.5V
0	0	0	0	3.5V	2.05V	6.0V	7.6V

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 assistance or to order, call [phone]

P T 7 7 2 0 S e r i e s

Ordering Information

PT7721 = 1.3 to 3.5 Volts

PT7722 = 4.5 to 7.6 Volts

(For dimensions and PC board layout, see Package Styles 1000 and 1010.)

PT Series Suffix (PT1234X)

Case/Pin

Configuration

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

C H A R A C T E R I S T I C		D A T A
Efficiency vs Output Current (@Vin=+12V)	Safe Operating Area (@Vin=+12V, Vout=+3.3V, Pkg N)

	100											(°C)	90
	90												80
(%)Efficiency	50										Vout	TemperatureAmbient	30	Recommended Maximum									Airflow
	80										5.0V		70
														Operating Temperature									200LFM
											3.3V		60
	70																						120LFM
											2.5V												60LFM
													50
											1.5V												Nat conv
	60
													40
	40												20
	0	2	4	6	8	10	12	14	16	18	20		0	2	4	6	8	10	12	14	16	18	20

Output Current (A) Output Current (A)

Output Ripple vs Output Current (@Vin=+12V)

Safe Operating Area (@Vin=+12V, Vout=+5.0V, Pkg N)

	16												90
	14											(°C)	80
	12										Vout
(mVpp)Ripple												TemperatureAmbient	70	Recommended Maximum									Airflow
	10										5.0V		30
													60	Operating Temperature									200LFM
											3.3V												120LFM
	8
											2.5V		50										60LFM
	6																						Nat conv
											1.5V
													40
	4
	2
	0												20
	0	2	4	6	8	10	12	14	16	18	20		0	2	4	6	8	10	12	14	16	18	20

Output Current (A)

Output Current (A)

Power Dissipation vs Output Current (@Vin=+12V)

	16
	14
	12										Vout
(Watts)	10										5.0V
	8										2.5V
											3.3V
Pd	6										1.5V
	4
	2
	0
	0	2	4	6	8	10	12	14	16	18	20
					Output Current (Amps)

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

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