onsemi MC33163DW

Overview

MC33163DW from onsemi is a monolithic switching regulator IC designed for step-up, step-down, and inverting dc-dc converter applications. It integrates a 3.4 A output switch, temperature-compensated 2% reference, controlled-duty-cycle oscillator, bootstrap-capable driver, cycle-by-cycle current limiting, and internal thermal shutdown. It operates from 2.5 V to 40 V input and delivers stable power in automotive body control modules requiring high-current, wide-input-range regulation.

For engineers reviewing the MC33163DW datasheet, pinout, applications, or equivalent options, key selection criteria include its −40°C to +85°C operating ambient range, SOIC-16W (Case 751G) heat-tab package with pins 4/5/12/13 as thermal ground path, 45–55 kHz oscillator frequency, and dual feedback comparators enabling precise 5.05 V or 1.25 V regulated outputs.

Technical Context

The MC33163DW implements a fixed on-time, variable off-time voltage-mode ripple control architecture-eliminating need for dominant-pole loop compensation. Its oscillator generates a sawtooth waveform (1.25 V peak / 0.55 V valley) via 225 µA charge / 25 µA discharge currents, yielding up to 90% max duty cycle.

Two independent high-impedance feedback comparators support dual regulation paths: FB1 (5.05 V internal reference, ±0.03 V total variation) for main output control and FB2 (1.225–1.287 V threshold, 15 mV hysteresis) for low-voltage indicator (LVI) generation. The LVI open-collector output sinks ≥6 mA and interfaces directly with microprocessor reset inputs.

Key Specifications

Pinout & Package

MC33163DW uses a 16-pin SOIC Wide Body (SOIC-16W, Case 751G) with integrated heat tab formed by pins 4, 5, 12, and 13 - soldered directly to PCB copper for enhanced thermal conduction. This surface-mount package replaces legacy DIP-16 variants while maintaining identical pin functions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC34163DWR2G, MC33163DW adds −40°C startup capability and automotive thermal robustness; compared with LM2577-ADJ, it integrates LVI, dual references, and cycle-by-cycle limiting-reducing BOM count by ≥4 components in safety-critical systems.

Availability

MC33163DW is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, medical auxiliary rails, and consumer set-top box designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC33163DW 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MC33163DW belongs to the MC34163/MC33163 series of monolithic switching regulators engineered for cost-sensitive, high-reliability dc-dc conversion in automotive and industrial environments where wide input range, integrated protection, and thermal resilience are mandatory.

FAQ

What is the maximum operating junction temperature for the MC33163DW?

The MC33163DW features internal thermal shutdown that activates at approximately 170°C junction temperature. Its absolute maximum rated operating junction temperature is +150°C per datasheet specifications. Sustained operation above this limit risks permanent damage, so PCB copper area and airflow must be designed to keep T_J ≤ 150°C under worst-case load and ambient conditions. The MC33163DW's SOIC-16W package relies on pins 4/5/12/13 as thermal ground path to achieve this.

Can the MC33163DW be used in a step-up (boost) configuration?

Yes, the MC33163DW supports step-up operation as confirmed in Figure 23 of its datasheet, delivering 28 V at 600 mA from a 12 V input with 88.1% efficiency. It uses the internal 3.4 A switch in low-side configuration with external inductor and Schottky rectifier (1N5822). The oscillator timing capacitor (CT) and feedback resistors (R1/R2) are selected per design equations in Figure 28 to meet voltage, current, and ripple targets.

Does the MC33163DW require an external bootstrap capacitor?

The MC33163DW includes an internal 2 mA bootstrap current source but requires an external bootstrap capacitor (CB) and series resistor to function. As detailed in the datasheet, CB must be sized to sustain the internal zener clamp (V_CC+7.0 V) under peak current demand; typical values are 0.02 µF ceramic with 10 Ω series resistance. Omitting CB degrades V_CE(sat) and reduces efficiency-e.g., from 81.2% to 76.7% in step-down tests.

How does the Low Voltage Indicator (LVI) output of the MC33163DW interface with a microprocessor?

The LVI output (Pin 1) is an open-collector NPN transistor sinking ≥6 mA when activated. To interface with a microprocessor reset input, connect Pin 1 to the MPU's reset pin via a pull-up resistor (e.g., 10 kΩ to V_CC). When V_CC drops below 1.125 V (with 15 mV hysteresis), the LVI asserts low, holding the MPU in reset until V_CC recovers above 1.14 V. An RC network (RLVI/CDLY) can add programmable delay per Equation in Section 8.

What is the minimum input voltage required for the MC33163DW to start switching?

The MC33163DW has a specified minimum operating supply voltage of 2.5 V, but Figure 16 shows functional operation down to 1.7 V at room temperature. However, reliable startup requires ≥3.0 V unless the bootstrap input (Pin 9) is tied directly to V_CC. Below 3.0 V, oscillator amplitude and comparator margins degrade; thus, 2.5 V is the guaranteed specification limit, and 3.0 V is recommended for robust design across −40°C to +85°C.