Texas Instruments PT6921C, PT6921N, PT6922A, PT6922C, PT6922N Datasheet

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P T 6 9 2 0 S e r i e s

Revised 3/9/99

Application Notes

5V TO 3.3V/2.5V 25 WATT DUAL OUTPUT

INTEGRATED SWITCHING REGULATOR Mechanical Outline

Product Selector Guide

Features

•Dual Outputs:

+3.3V/6A

+2.5V/2.2A or +1.8V/1.5A

•Adjustable Output Voltage

•Remote Sense (both outputs)

•Standby Function

•Over-Temperature Protection

•Soft-Start

•Internal Sequencing

•23-pin SIPPackage

Patent Pending*

The PT6920 is a new series of 25W dual output ISRs designed to power the latest generation DSP chips. Both output voltages are independently adjustable with external resistors. In addition, the second output voltage of the PT6921 can be selected for 2.5V or 1.8V to accommodate the next generation of DSP chips. The internal power sequencing of both outputs meet the latest requirements of TI’s ‘C6000 series DSPs.

Standard Application

C1 = Req’d 560µF electrolytic
C2 = Req’d 330µF electrolytic
C3 = Optional 100µF electrolytic							V2 Sense
STBY							V1 Sense
		3	22	1
					18-21		V2OUT
VIN	4,5,6	PT6920
					12-15		V1OUT
		7-11	16	23		R1	+
C1					R3		C3
							+
							C2
					R4	R2
GND							GND

Pin-Out Information

Pin	Function		Pin	Function
1	V1 Remote Sense		13	V1out
2	Do Not Connect		14	V1out
3	STBY		15	V1out
4	Vin		16	V1 Adjust
5	Vin		17	Do Not Connect
6	Vin		18	V2out
7	GND		19	V2out
8	GND		20	V2out
9	GND		21	V2out
10	GND		22	V2 Remote Sense
11	GND	23		V2 Adjust*
12	V1out

Ordering Information

PT6921 = +3.3 Volts

+2.5/+1.8 Volts

PT6922 = +3.3 Volts

+1.5 Volts

PT Series Suffix (PT1234X)

Case/Pin

Configuration

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

(For dimensions and PC board layout, see Package Styles 1100 and 1110.)

Note: for PT6921 only:

with pin23 open, V2out=2.5V

with pin 23 shorted to pin 22, V2out=1.8V

Preliminary Specifications

Characteristics							PT6920 SERIES
(Ta= 25°C unless noted)	Symbols		Conditions				Min	Typ	Max		Units
Output Current	Io		Ta = +60°C, 200 LFM, pkg N		V1 = 3.3V		0.1	—	5.5		A
					V2 = 2.5V		0	—	2.2		A
					V2 = 1.8V		0	—	1.75		A
					V2 = 1.2V		0	—	1.2		A
			Ta = +25°C, natural convection		V1 = 3.3V		0.1	—	6.0		A
					V2 = 2.5V		0	—	2.2		A
					V2 = 1.8V		0	—	1.75		A
					V2 = 1.2V		0	—	1.2		A
Input Voltage Range	Vin		0.1A ≤ Io ≤ Imax				4.5	—	5.5		V
Output Voltage Tolerance	Vo		Vin	= +5V, Io = Imax, both outputs			Vo-0.1	—	Vo+0.1		V
			0°C	≤ Ta ≤ +65°C
Line Regulation	Regline		4.5V ≤ Vin ≤ 5.5V, Io = Imax		V1 = 3.3V		—	±7	±17		mV
					V2 = 2.5V		—	±7	±13		mV
Load Regulation	Regload		Vin = +5V, 0.1 ≤ Io ≤ Imax		V1 = 3.3V		—	±17	±33		mV
					V2 = 2.5V		—	±4	±10		mV
Vo Ripple/Noise	Vn		Vin = +5V, Io = Imax		V1 = 3.3V		—	50	—		mV
					V2 = 2.5V		—	25	—		mV
Transient Response	ttr		Io step between 0.5xImax and Imax				—	25	—		µSec
with C2 = 330µF	Vos		Vo over/undershoot		V1 = 3.3V		—	60	—		mV
					V2 = 2.5V		—	60	—		mV
Efficiency	η		Vin = +5V, Io = 4A total				—	75	—	%
Switching Frequency	ƒo		4.5V ≤ Vin ≤ 5.5V				475	600	725		kHz
			0.1A ≤ Io ≤ Imax
Absolute Maximum	Ta		—				0	—	+85		°C
Operating Temperature Range
Recommended Operating	Ta		Forced airflow = 200 LFM				0	—	+65		°C
Temperature Range			Over Vin and Io Ranges
Storage Temperature	Ts		—				-40	—	+125		°C
Weight	—		Vertical/Horizontal				—	29	—		grams

Note: The PT6920 series requires a 560µF electrolytic capacitor on the input and a 330µF electrolytic capacitor on the output for proper operation in all applications. * This product is the subject of one or more patents. Other patents pending.

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

For assistance or to order, call [phone]

P T 6 9 2 0 S e r i e s

C H A R A C T E R I S T I C D A T A

PT6921, V2out = 2.5V, I2out = 2.2A (See Note 1)

	Total Efficiency vs I1out
	1 00
	9 0
	8 0						Vin
(%)							4 .5 V
Efficiency							5 .0 V
	7 0						5 .5 V
	6 0
	5 0
	4 0
	0	1	2	3	4	5	6
				I1out (A)
	Total Power Dissipation vs I1out
	1 0
	8
(Watts)							Vin
							5 .5 V
	6						4 .5 V
							5 .0 V
PD	4
	2
	0
	0	1	2	3	4	5	6
				I1out (A)
	V1out Ripple vs I1out
	5 0
	4 0
							Vin
(mV)	3 0						4 .5 V
							5 .0 V
Ripple							5 .5 V
	2 0
	1 0
	0
	0	1	2	3	4	5	6
				I1out (A)
	Safe Operating Area vs I1out
	90
	80
	70	Recommended Maximum					Nat conv.
(°C)
		Operating Temperature					60LF M
	60						200LF M
Ta
	50
	40
	30
	0	1	2	3	4	5	6
				I1out (A)

Note 1: All data listed in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the ISR.

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