UC1965 UC2965 UC3965 UDG-97001

UC2965 UC3965 Precision Reference with Low Offset Error Amplifier FEATURES · Accessible 2.5V Precision Reference ·

UC1965 UC1965 UC2965 UC2965 UC3965 UC3965 Precision Reference with Low Offset Error Amplifier FEATURES · Accessible 2.5V Precision Reference · 0.4% Initial Reference Accuracy · Low 1mV Offset Error Amplifier · 2X Inverting Amplifier / Buffer Output · 4.1V Undervoltage Lockout · DESCRIPTION ICC 2mA at 5V · PRELIMINARY 8-Pin SOIC or DIL Package The UC3965 UC3965 includes an accessible 2.5V precision reference, a low offset error amplifier, a 2X inverting amplifier/buffer and an undervoltage lockout circuit. The IC is ideally suited for applications where high precision PWM power supply regulation is required. Typically, the error amplifier is connected to compare a fraction of the "to be regulated" power supply voltage to the on-chip 2.5V reference. The 2X amplifier/buffer output is then used to drive a PWM controller or regulator. The UC3965 UC3965 is also capable of driving an optocoupler diode for isolated applications. BLOCK DIAGRAM UDG-97001 UDG-97001 1/97 UC1965 UC1965 UC2965 UC2965 UC3965 UC3965 CONNECTION DIAGRAM ABSOLUTE MAXIMUM RATINGS VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3V to 20V VREF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3V to 6V VFB, COMP, NI, VOUT . . . . . . . . . . . . . . . . . . . . 0.3V TO 6V 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. All voltages are with respect to ground. Consult Packaging Section of Databook for thermal limitations and considerations of packages. DIL-8, SOIC-8 (Top View) J or N Package, DP Package ELECTRICAL CHARACTERISTICS Unless otherwise specified, TA = 0°C to 70°C for the UC3965 UC3965, 40°C to 85°C for the UC2965 UC2965 and 55°C to 125°C for the UC1965 UC1965; VCC = 5V, TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 4.3 5 20 V 1.5 2 4 mA 200 µA General VCC Operating Current VCC = 5V Undervoltage Current Minimum Voltage to Start 3.9 4.1 4.3 V Hysteresis 200 300 400 mV VREF VREF Initial Accuracy 25°C 2.49 2.5 2.51 V VREF Over Temperature 55°C to 125°C 2.48 2.5 2.52 V Total Output Variation Line, Load, Temperature 2.475 2.5 2.525 V Line Regulation VCC = 4.3V to 20V 2 10 mV 10 Load Regulation 0µA to 500µA 2 Short Circuit Current VREF = 0V 2 Input Bias VCM = 2.5V 200 Input Offset Voltage VCM = 2.5V Input Offset Current VCM = 2.5V Gain Bandwidth Product VIN = 50mV P-P (Note 1) Open Loop Gain VOUT = 1V to 3.75V Output Low Level IOUT = 0µA IOUT = 100µA mV mA Error Amplifier Output High Level nA 1 100 400 2 mV 0 100 nA 6 100 dB 0.8 80 MHz V 1.2 V IOUT = 0µA 4 V IOUT = 500µA 4 V Short Circuit Circuit VCOMP = 0V 8 mA CMRR VCM = 1.25V to 3.75V 70 100 dB PSRR VCC = 4.3V to 20V 70 100 dB Rising Slew Rate 2 V/µs Falling Slew Rate 0.4 V/µs Inverting Buffer Amplifier 1 Input Bias VCM = 2.5V Output Offset Voltage VCM = 2.5V Gain Bandwidth Product VIN = 50mV P-P (Note 1) Closed Loop Gain Inverting Gain 20 µA 20 mV 1.5 2.04 2 2 0 2 MHz 1.96 V/V UC1965 UC1965 UC2965 UC2965 UC3965 UC3965 ELECTRICAL CHARACTERISTICS (cont.) Unless otherwise specified, TA = 0°C to 70°C for the UC3965 UC3965, 40°C to 85°C for the UC2965 UC2965 and 55°C to 125°C for the UC1965 UC1965; VCC = 5V; TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Inverting Buffer Amplifier (cont.) Output Low Level Output High Level IOUT = 0µA 0.3 V IOUT = 100µA 0.5 V 4 V IOUT = 0mA IOUT = 4mA 4 V Short Circuit Circuit VOUT = 0V 18 mA CMRR VCM = 1.25V to 3.75V 70 100 dB PSRR VCC = 4.3V to 20V 70 100 dB Rising Slew Rate 0.9 V/µs Falling Slew Rate 0.9 V/µs Note 1: Guaranteed by design. Not 100% tested in production. PIN DESCRIPTIONS COMP: Error amplifier output. VCC: VCC supply and UVLO input. GND: Ground. VFB: Error amplifier inverting input. NI: Error amplifier non-inverting input. VOUT: Inverting buffer output. OFFSET: Inverting buffer non-inverting input. VREF: VREF output. UNITRODE CORPORATION 7 CONTINENTAL BLVD. · MERRIMACK, NH 03054 TEL. (603) 424-2410 · FAX (603) 424-3460 3