NXP Semiconductors MCZ34701EW

Overview

MCZ34701EW from NXP Semiconductors (formerly Freescale) is a dual-output power management IC integrating a 1.5A synchronous buck switcher and an external-NMOS LDO controller for microprocessor core (VDDL) and I/O/bus (VDDH) rail generation. It operates from 2.8V–6.0V input, delivers 0.8V ±1.0% regulated outputs with programmable voltage margining via I²C, and supports precise up/down power sequencing for Power QUICC I/II and MPC8xxx families.

For engineers reviewing the MCZ34701EW datasheet, MCZ34701EW pinout, MCZ34701EW application, or MCZ34701EW equivalent, this page provides verified technical context on its dual-regulator architecture, 300 kHz default switching frequency, thermal shutdown at 170°C, I²C-addressable voltage margining, and 32-pin SOICW Pb-free package - all critical for CPU power supply design validation and BOM replacement.

Technical Context

The MCZ34701EW implements a synchronous buck converter with integrated high-side (60 mΩ) and low-side (65 mΩ) N-channel MOSFETs, driven by a 300 kHz oscillator adjustable via external resistor (200–400 kHz range). Its LDO control loop drives an external NMOS pass device (e.g., IRL2703), using LFB feedback and LCMP compensation to achieve <1.0% load/line regulation and 40 dB ripple rejection at 300 kHz.

Power sequencing is managed by dual enable inputs (EN1/EN2) selecting among four modes-including standard, inverted, or disabled sequencing-while the RST open-drain output monitors both VOUT and VLDO with ±0.5% UV/OV thresholds and 20 µs noise filtering. The I²C interface (SDA/SCL, 100 kHz max) enables real-time voltage margining, watchdog configuration, and reset delay programming via RT pin.

Key Specifications

Pinout & Package

MCZ34701EW uses a 32-pin SOICW (Wide-body) package with exposed thermal pad, optimized for power dissipation in space-constrained CPU power designs. Pin functions are validated per Freescale Document Number MC34701 Rev 7.0.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output CPU power supply applications.

Compared with TPS51200DRCR and ISL6263BIRZ, the MCZ34701EW uniquely combines integrated buck MOSFETs, external-NMOS LDO drive, I²C voltage margining, and QUICC-specific sequencing - making it irreplaceable for legacy Freescale CPU power without redesigning the entire power architecture.

Availability

MCZ34701EW is available at Aetrix Electronics and suitable for industrial embedded control, networking equipment power, and Power QUICC-based communications systems requiring stable component supply and long-term lifecycle support.

Supply support for MCZ34701EW 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

NXP Semiconductors acquired Freescale Semiconductor in 2015 and maintains full technical and supply chain support for legacy Freescale analog and power management products.

The MCZ34701EW belongs to Freescale's CPU power management IC family, specifically engineered to simplify power delivery for Power QUICC I/II and MPC8xxx microprocessors - emphasizing sequencing integrity, thermal robustness, and I²C configurability.

FAQ

What is the default switching frequency of the MCZ34701EW and how is it adjusted?

The MCZ34701EW defaults to 300 kHz switching frequency when the FREQ pin is left open or tied to VDDI. Frequency is adjusted using an external resistor RF connected between FREQ and ground: 7.0 kΩ yields ~400 kHz, 22 kΩ yields ~200 kHz, and values between 7–22 kΩ provide linear scaling across 200–400 kHz. This adjustment directly impacts inductor size, efficiency, and EMI profile in the final design.

Does the MCZ34701EW integrate power MOSFETs for both the buck and LDO sections?

The MCZ34701EW integrates N-channel MOSFETs for the synchronous buck converter (Q1/Q2, RDS(ON) = 60/65 mΩ), but does not integrate the LDO pass element. Instead, it provides LDRV gate drive and CS current sensing to control an external N-channel MOSFET (e.g., IRL2703) - enabling scalable LDO current beyond 1 A and optimized thermal partitioning in the MCZ34701EW design.

How does the MCZ34701EW implement power sequencing for Freescale microprocessors?

The MCZ34701EW uses EN1 and EN2 logic inputs to select among four sequencing modes defined in Table 5: Standard (EN1=0, EN2=1), Inverted (EN1=1, EN2=0), Disabled (EN1=0, EN2=0), or Enabled without sequencing (EN1=1, EN2=1). Each mode configures internal timing to enforce correct VDDL (core) and VDDH (I/O) ramp order and hold times required by Power QUICC I/II and MPC8xxx datasheets.

What is the function of the VBST pin on the MCZ34701EW and what voltage does it supply?

The VBST pin on the MCZ34701EW is the output of an internal charge-pump boost regulator, delivering a nominal 7.75 V (range 7.3–8.3 V) at up to 20 mA. This voltage powers the gate drivers for the internal buck MOSFETs (Q1/Q2) and the external LDO pass MOSFET (driven by LDRV), ensuring sufficient gate overdrive for low RDS(ON) operation across the full input voltage range of the MCZ34701EW.

Can the MCZ34701EW monitor and respond to overvoltage conditions on its output rails?

Yes, the MCZ34701EW continuously monitors both VOUT (buck) and VLDO (LDO) via dedicated comparators. The RST output asserts low if either rail deviates beyond ±0.5% for VOUT or ±4.0% for VLDO - providing active overvoltage and undervoltage protection. This supervision includes 20 µs noise filtering to prevent false triggers, and RST remains asserted until both rails stabilize within tolerance, ensuring safe CPU reset behavior in the MCZ34701EW system.