NXP Semiconductors MC34717EPR2

Overview

MC34717EPR2 from Freescale Semiconductor is a dual-channel synchronous buck switching regulator with integrated 50 mΩ N-channel MOSFETs, delivering up to 5.0 A per channel at ±1% output voltage accuracy (0.7–3.6 V), programmable 200 kHz–1.0 MHz switching frequency, and voltage tracking capability on Channel 2 for coordinated power sequencing in point-of-load applications.

For engineers reviewing the MC34717EPR2 datasheet, MC34717EPR2 pinout, MC34717EPR2 application, or MC34717EPR2 equivalent, key selection considerations include dual-channel current capability, thermal shutdown threshold (170 °C), active-low power-good signaling, soft-start programmability via ILIM pins, and QFN-26 exposed-pad package compatibility with high-density PCB layouts.

Technical Context

The MC34717EPR2 implements voltage-mode PWM control with two independent synchronous buck converters sharing a common oscillator and bias circuitry. Each channel features dedicated error amplifiers, compensation inputs (COMP1/COMP2), inverting inputs (INV1/INV2), and current-limit programming via ILIM1/ILIM2 pins.

Channel 2 supports external reference tracking via VREFIN, enabling precise rail-to-rail sequencing during startup/shutdown; internal discharge MOSFETs (M8/M9) actively sink VOUT1/VOUT2 during shutdown mode, ensuring fast, controlled rail collapse without external components.

Key Specifications

Pinout & Package

The MC34717EPR2 is housed in a thermally enhanced, Pb-free 26-pin QFN package with an exposed thermal pad (Pin 27). The package supports high-power dissipation (R_θJA = 32 °C/W on 4-layer board) and requires connection of the thermal pad to analog ground for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output synchronous buck regulator applications.

Compared with MP8765GQ-Z and TPS546D24RTWR, the MC34717EPR2 uniquely balances integration (dual channels + tracking + discharge), analog simplicity (no firmware or PMBus), and thermal robustness (170 °C shutdown) for cost-sensitive, high-reliability embedded power designs.

Availability

MC34717EPR2 is available at Aetrix Electronics and suitable for DDR memory power supplies, FPGA power sequencing, industrial PLC CPU modules, and automotive infotainment SoC supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC34717EPR2 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

Freescale Semiconductor (now part of NXP Semiconductors) is a global leader in embedded processing and analog power solutions, specializing in high-performance, thermally robust ICs for automotive, industrial, and computing markets.

The MC34717EPR2 belongs to Freescale's SMARTMOS point-of-load regulator family, designed specifically for space-constrained, high-current digital power delivery where integration, sequencing fidelity, and thermal resilience are critical.

FAQ

What is the maximum continuous output current per channel for the MC34717EPR2?

The MC34717EPR2 delivers up to 5.0 A of continuous output current per channel, provided junction temperature remains ≤150 °C. This rating assumes proper PCB thermal design (e.g., 4-layer board with thermal vias to ground plane) and operation within the 3.0–6.0 V input range. Both channels can sustain full 5.0 A simultaneously under appropriate thermal conditions.

How does the MC34717EPR2 implement voltage tracking between its two outputs?

The MC34717EPR2 implements voltage tracking using the VREFIN pin: Channel 2's error amplifier references the voltage applied to VREFIN (0.0–1.35 V), allowing VOUT2 to precisely follow VREFIN during startup and steady-state operation. When VREFIN rises above 0.7 V, Channel 2 defaults to its internal 0.7 V reference-enabling flexible tracking configurations such as ratio-matching or offset-based sequencing without external components.

What is the purpose of the VOUT1 and VOUT2 pins on the MC34717EPR2?

The VOUT1 and VOUT2 pins on the MC34717EPR2 serve as dedicated discharge paths for their respective output rails. During shutdown mode (SD = low), internal MOSFETs M8 and M9 actively sink current from VOUT1 and VOUT2, rapidly collapsing output voltages. This eliminates reliance on external bleed resistors and ensures controlled, fast rail discharge-critical for reliable power sequencing in FPGAs and DDR memory systems.

Can the switching frequency of the MC34717EPR2 be adjusted, and how is it set?

Yes, the MC34717EPR2 switching frequency is programmable from 200 kHz to 1.0 MHz using the FREQ pin. A resistor divider between VDDI and GND sets the frequency; tying FREQ directly to GND selects the default 1.0 MHz setting. Frequency adjustment allows optimization of efficiency, EMI, and external component size-higher frequencies reduce inductor and capacitor values while increasing switching losses.

Does the MC34717EPR2 include built-in protection features, and which ones are implemented?

Yes, the MC34717EPR2 integrates comprehensive protection: over-current limit (6.5 A typical per channel), short-circuit detection, thermal shutdown (170 °C threshold with 25 °C hysteresis), output over-voltage (±8% threshold), output under-voltage (±8% threshold), and active-low power-good (PG) fault reporting. All protections trigger automatic shutdown with configurable retry timers (e.g., 80–120 ms timeout), ensuring system-level reliability without external supervision circuitry.