Texas Instruments UCC381DPTR-ADJ, UCC381DPTR-5, UCC381DP-ADJ, UCC381DP-5, UCC381DP-3 Datasheet

UCC281-3/-5/-ADJ

UCC381-3/-5/-ADJ

Low Dropout 1 Ampere Linear Regulator Family

FEATURES

•Precision Positive Linear Voltage Regulation

•0.5V Dropout at 1A

•Guaranteed Reverse Input/ Output Voltage Isolation with Low Leakage

•Low Quiescent Current Irrespective of Load

•Adjustable Output Voltage Version

•Fixed Versions for 3.3V and 5V Outputs

•Logic Shutdown Capability

•Short Circuit Power Limit of 3% • VIN • Current Limit

•Remote Load Voltage for Accurate Load Regulation

DESCRIPTION

The UCC381-3/-5/-ADJ family of positive linear series pass regulators is tailored for low drop out applications where low quiescent power is important. Fabricated with a BiCMOS technology ideally suited for low input to output differential applications, the UCC381 will pass 1A while requiring only 0.5V of input voltage headroom. Dropout voltage decreases linearly with output current, so that dropout at 200mA is less than 100mV. Quiescent current is always less than 650 A. To prevent reverse current conduction, on-chip circuitry limits the minimum forward voltage to typically 50mV. Once the forward voltage limit is reached, the input-output differential voltage is maintained as the input voltage drops until undervoltage lockout disables the regulator.

UCC381-3 and UCC381-5 versions have on-chip resistor networks preset to regulate either 3.3V or 5.0V, respectively. Furthermore, remote sensing of the load voltage is possible by connecting the VOUTS pin directly at the load. The output voltage is then regulated to 1.5% at room temperature and better than 2.5% over temperature. The UCC381-ADJ version has a regulated output voltage programmed by an external user-definable resistor ratio.

(continued)

BLOCK DIAGRAM

VIN	8						1	VOUT
				VPUMP			4	VOUTS
			CURRENT		VOLTAGE		R2
					AMPLIFIER
			LIMIT
			–		–
	1.3/2.1A				+
			+
	CURRENT						2	GND
	REFERENCE
						1.25V	3	GND
	SHUTDOWN FOR FIXED VERSIONS
							R1
CT*	5						6	GND
		0.65V					7	GND
		3% DUTY CYCLE
	*ADJ	CURRENT LIMIT TIMER
	VERSION					R2	R1
	ONLY	REVERSE VOLTAGE
			SENSE		UCC381-ADJ	0	OPEN
				UVLO	UCC381-3	82k	50k
			THERMAL
			SHUTDOWN		UCC381-5	150k	50k

UDG-98112

SLUS214A - NOVEMBER 1999

ABSOLUTE MAXIMUM RATINGS

VIN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V CT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 to 3V Storage Temperature . . . . . . . . . . . . . . . . . . . −65°C to +150°C Junction Temperature. . . . . . . . . . . . . . . . . . . −55°C to +150°C Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C

Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages. All voltages are referenced to GND.

DESCRIPTION (cont.)

UCC281-3/-5/-ADJ

UCC381-3/-5/-ADJ

CONNECTION DIAGRAMS

SOIC-8 (Top View)

DP Package

VOUT	1	8	VIN
GND	2	7	GND
GND	3	6	GND
VOUTS	4	5	CT*

* ADJ version only

Short circuit current is internally limited. The device responds to a sustained overcurrent condition by turning off after a TON delay. The device then stays off for a pe-

riod, TOFF, that is 32 times the TON delay. The device then begins pulsing on and off at the TON /(TON+TOFF) duty cycle of 3%. This drastically reduces the power dis-

sipation during short circuit such that heat sinking, if at all required, must only accommodate normal operation. On the fixed output versions of the device TON is fixed at 400µs − a guaranteed minimum. On the adjustable version an external capacitor sets the on time. The off time is always 32 times TON.

The UCC381 can be shutdown to 25µA (max) by pulling the CT pin low.

Internal power dissipation is further controlled with thermal overload protection circuitry. Thermal shutdown occurs if the junction temperature exceeds 165°C. The chip will remain off until the temperature has dropped 20°C.

The UCC281 series is specified for operation over the industrial range of −40°C to +85°C, and the UCC381 series is specified from 0°C to +70°C. These devices are available in the 8 pin DP surface mount power package. For other packaging options consult the factory.

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications hold for TA = 0°C to 70°C for the

UCC381-X series and −40°C to +85°C for the UCC283-X series, VIN = VOUT + 1.5V, IOUT = 0mA, COUT = 2.2µF. CT = 1500pF for the UCC381-ADJ version and VOUT set to 5V. TJ = TA.

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
UCC381-5 Fixed 5V, 1A Family
Output Voltage	TJ = 25°C	4.925	5	5.075	V
	Over Temperature	4.875		5.125	V
Line Regulation	VIN = 5.15V to 9V		1	3	mV
Load Regulation	IOUT = 0mA to 1A		2	5	mV
Drop Out Voltage, VIN – VOUT	IOUT = 1A, VOUT = 4.85V, TA < 85°C		0.5	0.6	V
	IOUT = 200mA, VOUT = 4.85V, TA < 85°C		100	200	mV
Peak Current Limit	VOUT = 0V		2	3.5	A
Overcurrent Threshold		1		1.8	A
Current Limit Duty Cycle	VOUT = 0V		3	5	%
Overcurrent Time Out, TON	VOUT = 0V	400	750	1600	µs
Quiescent Current			400	650	µA
Quiescent Current in Shutdown	VIN = 9V		10	25	µA
Shutdown Threshold	At CT Input	0.25	0.65		V
Reverse Leakage Current	1V < VIN < VOUT, VOUT < 5.1V, at VOUT			75	µA
UVLO Threshold	VIN where VOUT passes current	2.5	2.8	3.0	V

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UCC281-3/-5/-ADJ

UCC381-3/-5/-ADJ

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications hold for TA = 0°C to 70°C for the

UCC381-X series and −40°C to +85°C for the UCC283-X series, VIN = VOUT + 1.5V, IOUT = 0mA, COUT = 2.2µF. CT = 1500pF for the UCC381-ADJ version and VOUT set to 5V. TJ = TA.

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
UCC381-3 Fixed 3.3V, 1A Family
Output Voltage	TJ = 25°C	3.25	3.3	3.35	V
	Over Temperature	3.22		3.38	V
Line Regulation	VIN = 3.45V to 9V		1	3	mV
Load Regulation	IOUT = 0mA to 1A		2	5	mV
Dropout Voltage, VIN - VOUT	IOUT = 1A, VOUT = 3.15V, TA < 85°C		0.6	0.8	V
	IOUT = 200mA, VOUT = 3.15V, TA < 85°C		100	200	mV
Peak Current Limit	VOUT = 0V		2	3.5	A
Overcurrent Threshold		1		1.8	A
Current Limit Duty Cycle	VOUT = 0V		3	5	%
Overcurrent Time Out, TON	VOUT = 0V	400	750	1600	µs
Quiescent Current			400	650	µA
Quiescent Current in Shutdown	VIN = 9V		10	25	µA
Shutdown Threshold	At CT Input	0.25	0.65		V
Reverse Leakage Current	1V < VIN < VOUT, VOUT < 3.35V, at VOUT			75	µA
UVLO Threshold	VIN where VOUT passes current	2.5	2.8	3.0	V
UCC381-ADJ Adjustable Output, 1A Family
Regulating Voltage at ADJ Input	TJ = 25°C	1.23	1.25	1.27	V
	Over Temperature	1.22		1.28	V
Line Regulation, at ADJ Input	VIN = VOUT + 150mV to 9V		1	3	mV
Load Regulation, at ADJ Input	IOUT = 0mA to 1A		2	5	mV
Dropout Voltage, VIN - VOUT	IOUT = 1A, VOUT = 4.85V		0.5	0.6	V
	IOUT = 200mA, VOUT = 4.85V		100	200	mV
Peak Current Limit	VOUT = 0V		2	3.5	A
Overcurrent Threshold		1		1.8	A
Current Limit Duty Cycle	VOUT = 0V		3	5	%
Overcurrent Time Out, TON	VOUT = 0V, CT = 1500pF	400	1000	1600	µs
Quiescent Current			400	650	µA
Quiescent Current in Shutdown	VIN = 9V		10	25	µA
Shutdown Threshold	At CT Input	0.25	0.65		V
Reverse Leakage Current	1V < VIN < VOUT, VOUT < 9V, at VOUT			100	µA
Bias Current at ADJ Input			100	250	nA
UVLO Threshold	VIN where VOUT passes current	2.5	2.8	3.0	V

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