onsemi MC34167D2T

Overview

MC34167D2T from onsemi is a fixed-frequency voltage-mode switching regulator IC designed for step-down, inverting, and step-up/down dc-dc converter topologies. It integrates a 5.0 A output switch, 72 kHz oscillator with on-chip timing, 5.05 V ±2% reference, cycle-by-cycle current limiting, and thermal shutdown. It operates from 7.5 V to 40 V input and supports automotive and industrial power supply designs requiring high-current regulation.

For engineers reviewing the MC34167D2T datasheet, pinout, applications, or equivalent options, key selection criteria include its 5.0 A switch current capability, D2PAK package thermal performance (θ_JC = 5.0 °C/W), 0–95% duty cycle range, undervoltage lockout with 0.9 V hysteresis, and standby mode reducing supply current to 36 µA.

Technical Context

The MC34167D2T implements voltage-mode PWM control using an internal error amplifier with 80 dB open-loop gain and 600 kHz unity-gain bandwidth, referenced to a trimmed 5.05 V bandgap. Its oscillator generates a 72 kHz ramp with 4.1 V/2.3 V thresholds, enabling up to 95% duty cycle and blanking during CT discharge to prevent multiple pulses per cycle.

Current protection uses cycle-by-cycle sensing via an internal resistor and comparator, triggering at 6.5 A typical (5.5–8.0 A min/max). Thermal shutdown activates at ~170 °C, and undervoltage lockout engages at 5.9 V (±0.4 V) with 0.9 V hysteresis - both functions disable the output latch to halt switching until conditions normalize.

Key Specifications

Pinout & Package

The MC34167D2T is housed in a surface-mount D2PAK (Case 936A) package with exposed tab thermally connected to Pin 3 (GND). The tab serves as primary heat path to PCB copper; θ_JC = 5.0 °C/W and θ_JA = 70 °C/W (with 25 mm² 2-oz copper).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switching regulator applications.

Compared with MC34167D2T, MC33167D2TR4G offers extended temperature operation without trade-offs in performance or pin compatibility, while LM2596S-5.0 sacrifices current capability, topology flexibility, and precision reference for lower cost and higher switching frequency in basic step-down use cases.

Availability

MC34167D2T is available at Aetrix Electronics and suitable for automotive body electronics, industrial programmable logic controllers, and embedded power conversion systems requiring stable component supply across production lifecycles.

Supply support for MC34167D2T 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MC34167 series belongs to onsemi's monolithic switching regulator product line, engineered specifically for robust, low-component-count dc-dc conversion in cost-sensitive and thermally constrained environments like automotive BCMs and industrial power modules.

FAQ

What is the maximum output current capability of the MC34167D2T?

The MC34167D2T integrates a high-current NPN switch rated for 5.0 A continuous output current. Its current limit threshold is specified at 5.5–8.0 A (typical 6.5 A), enabling reliable operation in step-down and inverting converters delivering up to 5 A without external pass devices. Thermal derating applies above +70 °C ambient.

Can the MC34167D2T be used in voltage-inverting configurations?

Yes, the MC34167D2T is explicitly designed for voltage-inverting topologies, as confirmed in its datasheet title and Figure 23. It achieves regulated negative outputs (e.g., −12 V/1.7 A) by re-referencing the ground pin to the negative output, leveraging its 0–95% duty cycle and internal 5.05 V reference to maintain regulation accuracy.

What package type does the MC34167D2T use, and how is thermal management handled?

The MC34167D2T uses the D2PAK (Case 936A) surface-mount package with an exposed thermal tab electrically and thermally connected to Pin 3 (GND). Its junction-to-case thermal resistance is 5.0 °C/W, requiring direct soldering to ≥25 mm² of 2-oz copper for effective heat dissipation in high-current applications.

Does the MC34167D2T support adjustable output voltages above 5.05 V?

Yes, the MC34167D2T supports adjustable outputs above 5.05 V using an external resistor divider at the FB (Pin 2) input. The output voltage is calculated as V_OUT = 5.05 × (1 + R2/R1), where R1 connects from FB to output and R2 from FB to ground - enabling precise regulation at any level within the device's duty cycle and voltage limits.

How does the standby mode function on the MC34167D2T?

The MC34167D2T enters low-power standby mode when the compensation pin (Pin 5) voltage is held below 0.15 V, reducing supply current to 36 µA at 12 V. This is implemented by clamping Pin 5 via external circuitry (e.g., transistor or comparator), allowing energy-efficient holdover in battery-powered or always-on systems without disabling regulation.