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 ToleranceApplicationThe 0.4% initial reference makes the UC39431 ideal as a programmable shunt regulator. By adding two external resistors, the on-chip 1.3V reference can be gained to any voltage between 2.2V (2.4V for the UC39431) and 36.0V. The input bias current is typically maintained at 0.2µA for the output voltage range. Since the non-inverting error amplifier input is not available, a 5.1k non-inverting input impedance is added to the input of the error amplifier. This allows the user to choose the SENSE pin input impedance to cancel the minimal offset voltage caused by the input bias current.
Pinout
SpecificationsSupply 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 (DIL-8) . . . . . . . . . . .. . . . . . . 1W
Derate 8mW for TA > 25
Storage Temperature Range . . . . . . . . . . . ..... . 65to +150
Junction Temperature. . . . . . . . . . . . . . . . . . .... 55 to +150
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . .... . +300
Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.
DescriptionThe UC39431B 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 UC39431B 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.
UC39431B Data Sheet
