Texas Instruments UC3715N

Overview

UC3715N from Texas Instruments is a high-speed complementary switch FET driver IC designed for synchronous rectification and active clamp/reset circuits. It features independently programmable 50–500 ns delays between AUX and PWR outputs, 1-A source / 2-A sink power driver capability, 0.5-A source / 1-A sink auxiliary driver, TTL-compatible INPUT, and ENBL-activated 220-μA sleep mode. It operates in 0°C to 70°C ambient and supports up to 1 MHz switching frequency in forward and flyback converters.

For engineers reviewing the UC3715N datasheet, UC3715N pinout, UC3715N application, or UC3715N equivalent, this device is selected for zero-voltage switching (ZVS) timing control, gate-drive sequencing in dual-FET topologies, delay-critical synchronous rectifier designs, and low-quiescent-current power management in isolated DC-DC stages.

Technical Context

The UC3715N implements independent RC-programmable dead-time control via T1 (AUX→PWR delay) and T2 (PWR→AUX delay), with nominal internal timer voltage of 3 V and ±1 mA current limiting. Its dual-output architecture separates logic-level input timing from high-current gate drive paths, enabling precise soft-switching transitions without external logic.

Propagation delays are tightly controlled: typical 35–100 ns for PWR output and 35–80 ns for AUX output, with rise/fall times under 60 ns into 2200 pF (PWR) and 1000 pF (AUX) loads. The ENBL pin directly enables a 220-μA sleep mode where PWR output remains active-low while AUX goes high-impedance.

Key Specifications

Pinout & Package

UC3715N is housed in an 8-pin PDIP (Plastic Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin spacing complies with JEDEC MS-001, supporting standard wave-solder and manual assembly processes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar complementary FET driver applications.

Compared with UC3714N and UC2715N, the UC3715N provides optimal timing flexibility for N-channel synchronous rectifiers due to its inverted AUX output, while maintaining compatibility with legacy UC37xx PCB layouts and offering the lowest-cost solution for commercial-temperature power supplies.

Availability

UC3715N is available at Aetrix Electronics and suitable for forward converters, flyback clamps, synchronous rectifiers, and intermittent-mode power supplies requiring stable component supply and long-term obsolescence management.

Supply support for UC3715N 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 specializing in analog, embedded processing, and power management technologies with over 50 years of power conversion innovation.

The UC37xx family was developed specifically for high-frequency, zero-voltage-switching DC-DC topologies requiring precise, independently programmable gate-drive timing in cost-sensitive commercial power supplies.

FAQ

What is the maximum operating frequency supported by the UC3715N?

The UC3715N supports switching frequencies up to 1 MHz, as confirmed in the datasheet's FEATURES section and validated by propagation delay (≤100 ns) and rise/fall time (≤60 ns) specifications. This makes UC3715N suitable for high-density AC-DC adapters and telecom DC-DC modules where fast switching reduces magnetics size. Actual usable frequency depends on external gate capacitance and layout parasitics, but UC3715N itself imposes no fundamental limit below 1 MHz.

How does the UC3715N implement zero-voltage switching (ZVS) support?

The UC3715N implements ZVS support via true zero-voltage sensing on its T1 and T2 pins: pulling either pin below 2.5 V immediately activates the corresponding output, bypassing RC delay. This allows direct connection to resonant node voltage dividers or comparators to trigger gate drive precisely at zero-crossing. Unlike fixed-delay operation, this feature enables adaptive timing in LLC or phase-shifted full-bridge designs - a capability explicitly documented in Figure 8 and PIN DESCRIPTIONS of the UC3715N datasheet.

What is the function of the ENBL pin on the UC3715N?

The ENBL pin on the UC3715N is a TTL-compatible enable input that places the device into a 220-μA sleep mode when held ≤0.8 V. In this state, the PWR output is actively held low regardless of VCC or INPUT state, while AUX becomes high-impedance. This behavior is specified in the ELECTRICAL CHARACTERISTICS table (ICC sleep mode = 200–300 µA) and PIN DESCRIPTIONS. It enables efficient standby operation in energy-compliant power supplies without requiring external discharge paths.

Can the UC3715N drive both N-channel and P-channel MOSFETs simultaneously?

Yes - the UC3715N's inverted AUX output and non-inverted PWR output allow direct drive of complementary N-channel + P-channel pairs, such as in active clamp forward converters. The datasheet confirms this in the DESCRIPTION ("designed to provide drive waveforms for complementary switches") and PIN DESCRIPTIONS ("In the UC1714 series, the AUX output is inverted to allow driving a p-channel MOSFET"). While UC3715N belongs to the UC37xx series (not UC17xx), its functional equivalence to UC1715 is established in the DEVICE INFORMATION and APPLICATIONS sections, confirming identical AUX inversion behavior.

What package types are offered for the UC3715N?

The UC3715N is offered exclusively in the 8-pin PDIP (Plastic Dual In-line Package) with 0.3-inch width, as confirmed in the PACKAGE OPTION ADDENDUM table where "UC3715N" lists Package Type = "PDIP" and Package Drawing = "P". No SOIC or other variants exist for the "N" suffix - UC3715D is the SOIC-8 version. The PDIP package supports through-hole assembly and is rated for 0°C to 70°C operation, matching the UC3715N's specified ambient temperature range.