Texas Instruments UCC2802PW

Overview

UCC2802PW from Texas Instruments is a low-power BiCMOS current-mode PWM controller for off-line and DC-DC fixed-frequency switching power supplies. It features 100 μA start-up supply current, 500 μA typical operating current, 100% maximum duty cycle, 12.5 V turn-on UVLO threshold, and 70 ns current-sense-to-output response - enabling compact, high-efficiency AC/DC adapters and industrial PSU designs.

For engineers reviewing the UCC2802PW datasheet, UCC2802PW pinout, UCC2802PW application, or UCC2802PW equivalent, key selection considerations include its 12.5 V/8.3 V UVLO hysteresis, internal leading-edge blanking (100 ns), 1.5% reference tolerance, totem-pole 1 A output drive, and pin compatibility with UC3842/UC3842A - all critical for reliable overvoltage protection and gate-drive timing in isolated flyback topologies.

Technical Context

The UCC2802PW implements a fixed-frequency, current-mode control architecture with dual comparators on the CS pin (PWM + overcurrent fault), digital leading-edge blanking synchronized to OUT rising edge, and a true low-impedance 2-MHz error amplifier capable of sourcing/sinking COMP current. Its oscillator uses REF-derived charging current and RC timing, supporting up to 1 MHz operation with ±2.5% frequency stability.

Unlike UC3842, the UCC2802PW integrates full-cycle soft start (4 ms COMP ramp), eliminates external RC filtering on CS in most designs, and provides higher UVLO hysteresis (4.2 V) for robust line brownout immunity in off-line applications - while maintaining identical SOIC/TSSOP 8-pin layout for drop-in evaluation.

Key Specifications

Pinout & Package

Packaged in an 8-pin TSSOP (PW), the UCC2802PW uses a surface-mount footprint measuring 4.40 mm × 3.00 mm with 0.65 mm lead pitch. Thermal resistance R_θJA is 117.9 °C/W, suitable for convection-cooled industrial PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-mode PWM controller applications.

Compared with UC3842N and UCC2803DR, the UCC2802PW delivers superior line transient immunity via 4.2 V UVLO hysteresis, eliminates CS filtering overhead, and enables higher-frequency operation - making it optimal for compact, high-reliability off-line power supplies where board space and startup robustness are critical.

Availability

UCC2802PW is available at Aetrix Electronics and suitable for industrial AC/DC adapters, isolated flyback PSUs, and automotive battery chargers requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.

Supply support for UCC2802PW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in power conversion and industrial control solutions.

The UCC280x product line was designed specifically for high-efficiency, low-component-count current-mode switching power supplies - targeting off-line AC/DC, DC-DC, and battery-operated systems where reliability, thermal performance, and design simplicity are paramount.

FAQ

What is the UVLO threshold behavior of the UCC2802PW?

The UCC2802PW features an undervoltage lockout with a 12.5 V turn-on threshold and 8.3 V turn-off threshold, yielding 4.2 V hysteresis. This wide hysteresis prevents oscillatory startup during AC line sags and ensures clean enable/disable sequencing in universal-input power supplies. The internal Zener clamps VCC at 13.5 V, protecting the device during overvoltage events. This behavior is confirmed in Section 6.5 of the UCC2802PW datasheet and applies specifically to the PW-package variant.

Does the UCC2802PW require an external RC filter on the CS pin?

No, the UCC2802PW does not require an external RC filter on the CS pin in most applications due to its integrated 100 ns digital leading-edge blanking circuit. This feature disconnects the CS input from both the PWM and overcurrent comparators for 100 ns after each OUT rising edge, effectively suppressing switch-node noise. External filtering is only needed in exceptionally noisy environments or when using very high dV/dt MOSFETs. This capability is explicitly documented in the UCC2802PW datasheet Section 5 and Figure 7-3.

How does the UCC2802PW soft-start function differ from UC3842?

The UCC2802PW implements internal full-cycle soft start with a fixed 4 ms COMP voltage ramp from 0.5 V to 5 V, eliminating the need for external soft-start components (resistor, capacitor, transistor). In contrast, the UC3842 requires an external RC network tied to the COMP pin. This integrated approach reduces BOM count, improves consistency across units, and avoids timing drift with temperature - all confirmed in UCC2802PW datasheet Sections 3 and 7.3.1.1.

Can the UCC2802PW replace UC3842 in existing designs?

The UCC2802PW shares identical pinout and basic functional blocks with UC3842, enabling direct PCB footprint replacement. However, it is not a plug-in replacement: differences in UVLO thresholds, COMP drive capability (low-Z vs open-collector), and internal blanking require verification of startup behavior, loop stability, and current-sense scaling. TI confirms pin compatibility but recommends re-evaluating compensation and gate drive in the UCC2802PW datasheet Section 7.3.

What is the maximum oscillator frequency supported by the UCC2802PW?

The UCC2802PW supports oscillator frequencies up to 1 MHz, as specified in its "Features" list and Section 6.5 Electrical Characteristics. This is double the 500 kHz limit of UC3842-family controllers. Achieving 1 MHz requires appropriate RC timing values (e.g., 100 kΩ resistor + 150 pF capacitor) and careful PCB layout - particularly short, direct grounding of the RC capacitor - per recommendations in UCC2802PW datasheet Section 5 and Figure 6-3.