UC28025 Series

Double ended economy high speed PWM controller

Catalog

Double ended economy high speed PWM controller

Part	Topology	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Duty Cycle (Max) [Max]	Operating Temperature [Max]	Operating Temperature [Min]	Package / Case [x]	Package / Case	Package / Case [y]	Output Configuration	Supplier Device Package	Control Features	Output Phases	Function	Mounting Type	Number of Outputs	Frequency - Switching [Min]	Frequency - Switching [Max]	Output Type	Package / Case	Package / Case
Texas Instruments UC28025DW	Boost Flyback Forward Converter Full-Bridge Half-Bridge Push-Pull	30 V	9 V	45 %	105 °C	-40 °C	0.295 in	16-SOIC	7.5 mm	Positive	16-SOIC	Current Limit Enable Frequency Control Ramp Soft Start	2	Step-Up Step-Up/Step-Down	Surface Mount	2	340 kHz	460 kHz	Transistor Driver
Texas Instruments UC28025NG4	Boost Flyback Forward Converter Full-Bridge Half-Bridge Push-Pull	30 V	9 V	45 %	105 °C	-40 °C		16-DIP		Positive	16-PDIP	Current Limit Enable Frequency Control Ramp Soft Start	2	Step-Up Step-Up/Step-Down	Through Hole	2	340 kHz	460 kHz	Transistor Driver	0.3 in	7.62 mm
Texas Instruments UC28025N	Boost Flyback Forward Converter Full-Bridge Half-Bridge Push-Pull	30 V	9 V	45 %	105 °C	-40 °C		16-DIP		Positive	16-PDIP	Current Limit Enable Frequency Control Ramp Soft Start	2	Step-Up Step-Up/Step-Down	Through Hole	2	340 kHz	460 kHz	Transistor Driver	0.3 in	7.62 mm
Texas Instruments UC28025DWR	Boost Flyback Forward Converter Full-Bridge Half-Bridge Push-Pull	30 V	9 V	45 %	105 °C	-40 °C	0.295 in	16-SOIC	7.5 mm	Positive	16-SOIC	Current Limit Enable Frequency Control Ramp Soft Start	2	Step-Up Step-Up/Step-Down	Surface Mount	2	340 kHz	460 kHz	Transistor Driver

Catalog

Double ended economy high speed PWM controller

Key Features

• Peak Current Mode, Average Current Mode, or Voltage Mode (With FeedForward) Control MethodsPractical Operation Up to 1 MHz50-ns Propagation Delay to Output±1.5-A Peak Totem Pole Outputs9-V to 30-V Nominal Operational VoltageWide Bandwidth Error AmplifierFully Latched Logic With Double Pulse SuppressionPulse-by-Pulse Current LimitingProgrammable Maximum Duty Cycle ControlUndervoltage Lockout With HysteresisTrimmed 5.1-V Reference With UVLOSame Functionality as UC3823 and UC3825Peak Current Mode, Average Current Mode, or Voltage Mode (With FeedForward) Control MethodsPractical Operation Up to 1 MHz50-ns Propagation Delay to Output±1.5-A Peak Totem Pole Outputs9-V to 30-V Nominal Operational VoltageWide Bandwidth Error AmplifierFully Latched Logic With Double Pulse SuppressionPulse-by-Pulse Current LimitingProgrammable Maximum Duty Cycle ControlUndervoltage Lockout With HysteresisTrimmed 5.1-V Reference With UVLOSame Functionality as UC3823 and UC3825

Description

The UC28023 and UC28025 are fixed-frequency PWM controllers optimized for high-frequency switched-mode power-supply applications. The UC28023 is a single output PWM for single-ended topologies while the UC28025 offers dual alternating outputs for double-ended and full bridge topologies. Targeted for cost-effective solutions with minimal external components. UC2802x devices include an oscillator, a temperature compensated reference, a wide bandwidth error amplifier, a high-speed current-sense comparator, and high-current, active-high, totem-pole outputs to directly drive external MOSFETs. Protection circuitry includes a current limit comparator with a 1-V threshold, a TTL compatible shutdown port, and a soft-start pin which doubles as a maximum duty-cycle clamp. The logic is fully latched to provide jitter-free operation and prohibit multiple pulses at an output. An undervoltage lockout section with 800 mV of hysteresis assures low start-up current. During undervoltage lockout, the outputs are high impedance. Propagation delays through the comparators and logic circuitry have been minimized while maximizing bandwidth and slew rate of the error amplifier. Devices are available in the industrial temperature range of –40°C to 105°C. Package offerings are 16-pin SOIC (DW), or 16-pin PDIP (N) packages. The UC28023 and UC28025 are fixed-frequency PWM controllers optimized for high-frequency switched-mode power-supply applications. The UC28023 is a single output PWM for single-ended topologies while the UC28025 offers dual alternating outputs for double-ended and full bridge topologies. Targeted for cost-effective solutions with minimal external components. UC2802x devices include an oscillator, a temperature compensated reference, a wide bandwidth error amplifier, a high-speed current-sense comparator, and high-current, active-high, totem-pole outputs to directly drive external MOSFETs. Protection circuitry includes a current limit comparator with a 1-V threshold, a TTL compatible shutdown port, and a soft-start pin which doubles as a maximum duty-cycle clamp. The logic is fully latched to provide jitter-free operation and prohibit multiple pulses at an output. An undervoltage lockout section with 800 mV of hysteresis assures low start-up current. During undervoltage lockout, the outputs are high impedance. Propagation delays through the comparators and logic circuitry have been minimized while maximizing bandwidth and slew rate of the error amplifier. Devices are available in the industrial temperature range of –40°C to 105°C. Package offerings are 16-pin SOIC (DW), or 16-pin PDIP (N) packages.