Texas Instruments UC2842AQDR

Overview

UC2842AQDR from Texas Instruments is a current-mode PWM controller in SOIC-14 package, designed for off-line and DC-DC converters. It features 16 V UVLO turn-on threshold, <50% maximum duty cycle, 500 kHz operation, ±1 A totem-pole output drive, and –40°C to 125°C extended temperature range-enabling robust control in industrial power supplies and battery-operated PSUs.

For engineers reviewing the UC2842AQDR datasheet, UC2842AQDR pinout, UC2842AQDR application, or UC2842AQDR equivalent, key selection criteria include its fixed <50% duty cycle limit, 8.3 mA trimmed oscillator discharge current, under-voltage lockout hysteresis, pulse-by-pulse current limiting, and compatibility with flyback and forward converter topologies requiring precise peak-current mode control.

Technical Context

The UC2842AQDR implements a current-mode control architecture with a high-gain (90 dB) error amplifier, internal 5 V bandgap reference, and dedicated ISENSE comparator for cycle-by-cycle current limiting. Its oscillator uses external RT/CT components to set frequency up to 500 kHz, with discharge current trimmed to 8.3 mA for stable timing.

It integrates double-pulse suppression, automatic feed-forward compensation, and a 1-A totem-pole output stage capable of sinking and sourcing gate drive current. The device operates only when VCC exceeds 16 V (UVLO ON), remains active down to 10 V (UVLO OFF), and disables output below that threshold with hysteresis.

Key Specifications

Pinout & Package

UC2842AQDR is housed in a 14-pin SOIC (D) package measuring 8.65 mm × 6.00 mm, with 1.27 mm lead pitch and 1.75 mm max height. Pin 1 is marked by a beveled corner or notch; the package is RoHS-compliant with NIPDAU lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UC2842AD and UC3842N, UC2842AQDR offers industrial temperature qualification, dedicated PWR GND for noise isolation, and guaranteed 8.3 mA oscillator discharge trim-making it optimal for ruggedized, high-reliability power designs where thermal margin and layout-controlled EMI matter.

Availability

UC2842AQDR is available at Aetrix Electronics and suitable for industrial switch-mode PSUs, offline flyback converters, battery-operated DC-DC modules, and telecom DC-DC converters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for UC2842AQDR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The UC284xA family was engineered specifically for current-mode control of isolated and non-isolated switched-mode power supplies, emphasizing startup reliability, thermal robustness, and integration of critical functions-including UVLO, error amplification, and gate drive-into a single IC.

FAQ

What is the UVLO hysteresis of UC2842AQDR?

The UC2842AQDR has a UVLO turn-on threshold of 16 V and turn-off threshold of 10 V, yielding 6 V of hysteresis. This prevents oscillatory behavior during input voltage ramp-up or brownout events. The hysteresis is inherent to the internal comparator design and does not require external components. This behavior is fully specified in the Electrical Characteristics table of the UC2842AQDR datasheet and applies across the full –40°C to 125°C operating range.

Can UC2842AQDR drive a MOSFET directly without a gate driver?

Yes, UC2842AQDR can drive medium-power MOSFETs directly: its OUTPUT pin sources and sinks up to ±1 A, sufficient for devices with gate charge ≤50 nC at typical 500 kHz frequencies. A series gate resistor (e.g., 10 Ω) is mandatory to control dV/dt and reduce EMI. For high-side or high-gate-charge applications (>100 nC), an external driver remains recommended. This capability is confirmed in the Absolute Maximum Ratings and Electrical Characteristics sections of the UC2842AQDR datasheet.

What is the maximum switching frequency supported by UC2842AQDR?

The UC2842AQDR supports up to 500 kHz operation, as stated in its Features list and verified in the Oscillator Section of the Electrical Characteristics table. Frequency is set externally via RT and CT components, with TI recommending RT = 5 kΩ–100 kΩ and CT = 470 pF–4.7 nF. At 500 kHz, propagation delays (e.g., 150–300 ns ISENSE-to-output) and rise/fall times (25–150 ns) remain within specification, enabling stable high-frequency control in compact power designs using UC2842AQDR.

Does UC2842AQDR include slope compensation for duty cycles above 50%?

No, UC2842AQDR does not include internal slope compensation. Its maximum duty cycle is fixed at <50%, eliminating subharmonic oscillation risk in standard flyback or forward converters. For topologies requiring >50% duty (e.g., active-clamp forward), external slope compensation-via resistive summation of the oscillator ramp into the ISENSE node-is required, as shown in Figure 8-3 of the UC2842AQDR datasheet. This design choice simplifies implementation for common single-ended applications while maintaining stability.

What package type and pin count does UC2842AQDR use?

UC2842AQDR uses a 14-pin SOIC (D) package with 8.65 mm × 6.00 mm dimensions, 1.27 mm lead pitch, and 1.75 mm max height. This is distinct from the 8-pin SOIC variant (e.g., UC2842AQD8R). The 14-pin version provides dedicated PWR GND and VS pins for improved noise isolation and flexible gate drive configurations. Package details, including mechanical drawings and tape-and-reel specifications, are documented in the Packaging section of the UC2842AQDR datasheet.