Texas Instruments UC39431N, UC39431DTR, UC39431D, UC29431DTR, UC29431D Datasheet

Precision Adjustable Shunt Regulator

UC19431

UC29431

UC39431

UC39431B

FEATURES

•Multiple On-Chip Programmable Reference Voltages

•0.4% Initial Accuracy

•0.7% Overall Reference Tolerance

•2.2V to 36.0V Operating Supply Voltage and User Programmable Reference

•36.0V Operating Supply Voltage

•Reference Accuracy Maintained For Entire Range of Supply Voltage

•Superior Accuracy and Easier Compensation for Optoisolator Application

•Improved Architecture Provides a Known Linear Transconductance with a +5% Typical Tolerance

DESCRIPTION

The UC39431 is an adjustable shunt voltage regulator with 100mA sink capability. The architecture, comprised of an error amplifier and transconductance amplifier, gives the user separate control of the small signal error voltage frequency response along with a fixed linear transconductance. A minimum 3MHz gain bandwidth product for both the error and transconductance amplifiers assures fast response. In addition to external programming, the IC has three internal resistors that can be connected in six different configurations to provide regulated voltages of 2.82V, 3.12V, 5.1V, 7.8V, 10.42V, and 12.24V. A sister device (UC39432) provides access to the non-inverting error ampilifer input and reference, while eliminating the three internal resistors.

BLOCK DIAGRAM

UDG-95087

04/99

ABSOLUTE MAXIMUM RATINGS

Supply Voltage: V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36V Regulated Output: V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36V Internal Resistors: R1, R2, R3. . . . . . . . . . . . . . . . . . . . . . . 13V E/A Input: SENSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V E/A Compensation: COMP . . . . . . . . . . . . . . . . . . . . . . . . . . 6V Output Sink Current: I. . . . . . . . . . . . . . . . . . . . . . . . . . . 140mA Power Dissipation at TA ≤ 25°C (DIL-8) . . . . . . . . . . . . . . . . . 1W Derate 8mW/°C for TA > 25°C

Storage Temperature Range . . . . . . . . . . . . . –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.

UC19431

UC29431

UC39431

UC39431B

CONNECTION DIAGRAM

DIL-8, SOIC-8 (Top View)

N or J, D Package

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –55°C to +125°C and COLL Output = 2.4V to 36.0V for the UC19431, TA = –25°C to +85°C and COLL Output = 2.3V to 36.0V for the UC29431, and TA = 0°C to +70°C and COLL Output = 2.3V to 36.0V for the UC39431/B, VCC = 15V, ICOLL = 10mA, TA = TJ.

PARAMETER	TEST CONDITIONS		MIN	TYP	MAX	UNITS
Reference Voltage Tolerance	TA = 25°C	19431*	1.295	1.3	1.305	V
		39431B	1.29	1.3	1.31	V
Reference Temperature Tolerance	VCOLL = 5.0	19431*	1.291	1.3	1.309	V
		39431B	1.286	1.3	1.314	V
Reference Line Regulation	VCC = 2.2V to 36.0V, VCOLL = 5V	19431*		10	38	mV
Reference Load Regulation	ICOLL = 10mA to 50mA, VCOLL = 5V	39431B		10	57	mV
		19431*		10	38	mV
		39431B		10	57	mV
Sense Input Current			–0.5	–0.2		A
Minimum Operating Current	VCC = 36.0V, VCOLL = 5V			0.50	0.80	mA
Collector Current Limit	VCOLL = VCC = 36.0V, Ref = 1.35V			130	145	mA
Collector Saturation	ICOLL = 20mA		0.7	1.1	1.5	V
Transconductance (gm)	VCC = 2.4V to 36.0V,	19431*	–170	–140	–110	mS
	VCOLL = 3V, ICOLL = 20mA	39431B	–180	–140	–100	mS
5.1V Reference	Internal Divider	19431*	5.05	5.1	5.15	V
		39431B	5	5.1	5.2	V
12.24V Reference	Internal Divider	19431*	12	12.24	12.5	V
		39431B	12	12.24	12.5	V
Error Amplifier AVOL			60	90		dB
Error Amplifier GBW	(Note 1)		3.0	5		MHz
Transconductance Amplifier GBW				3		MHz

* Also applies to the UC29431 and UC39431

Note: The internal divider can be configured to give six unique references. These references are 2.82V, 3.12V, 5.1V, 7.8V, 10.42V, 12.24V.

Note 1: Guaranteed by design. Not 100% tested in production.

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PIN DESCRIPTIONS (cont.)

COLL: The collector of the output transistor with a maximum voltage of 36V. This pin is the output of the transconductance amplifier. The overall open loop voltage gain of the transconductance amplifier is gm • RL, where gm is designed to be –140mS ±30mS and RL represents the output load.

COMP: The output of the error amplifier and the input to the transconductance amplifier. This pin is available to compensate the high frequency gain of the error amplifier. It is internally voltage limited to approximately 2.0V.

GND: The reference and power ground for the device. The power ground of the output transistor is isolated on the chip from the substrate ground used to bias the remainder of the device.

R1, R2, R3: Connection points to the three internal resistors.

SENSE: The inverting terminal of the error amplifier used as both the voltage sense input to the error amplifier and its other compensation point. The error amplifier uses the SENSE input to compare against the 1.3V on-chip reference.

UC19431

UC29431

UC39431

UC39431B

The SENSE pin is also used as the undervoltage lockout (UVLO). It is intended to keep the chip from operating until the internal reference is properly biased. The threshold is approximately 1V. It is important that once the UVLO is released, the error amplifier can drive the transconductance amplifier to stabilize the loop. If a capacitor is connected between the SENSE and COMP pins to create a pole, it will limit the slew rate of the error amplifier. To increase the bandwidth and ensure startup at low load current, it is recommended to create a zero along with the pole as shown in the shunt regulator application. The error amplifier must slew 2.0V to drive the transconductance amplifier initially on.

VCC: The power connection for the device. The minimum to maximum operating voltage is 2.2V to 36.0V. The quiescent current is typically 0.50mA.

UDG-95088

Figure 1. Typical 5.1V shunt regulator application.

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