STMicroelectronics EVAL5973AD

Overview

EVAL5973AD from STMicroelectronics is an evaluation board for the L5973AD 2 A step-down switching regulator IC, designed to demonstrate adjustable 1.235–35 V output operation with 500 kHz fixed-frequency PWM control, internal P-channel MOSFET (200 mΩ R_DS(on)), and synchronization capability in HSOP8 exposed-pad package. It supports input voltages from 4 V to 36 V and enables rapid validation of DC-DC converter designs for industrial power supplies and embedded systems.

For engineers reviewing the EVAL5973AD datasheet, EVAL5973AD pinout, EVAL5973AD application, or EVAL5973AD equivalent, this board provides verified reference circuitry-including 15 μH inductor, STPS2L25U Schottky diode, 10 μF ceramic input cap, 330 μF POSCAP output cap, and resistor-divider feedback network-for evaluating thermal performance, efficiency (up to 90% at 5 V_OUT/12 V_IN), load regulation, and INH/SYNC functionality under real-world conditions.

Technical Context

The EVAL5973AD implements a non-isolated buck topology using the L5973AD controller IC, which integrates a high-side P-MOSFET switch, transconductance error amplifier, 500 kHz oscillator with voltage feedforward, pulse-by-pulse current limiting, and thermal shutdown. Its test circuit operates with 4–25 V input (limited by C1 rating) and delivers up to 2 A output current at 3.3 V with <±2% reference accuracy (3.3 V ±66 mV).

Key functional blocks include the COMP pin for Type II/III compensation, FB pin referenced to 1.235 V internal bandgap, SYNC pin supporting master/slave configuration, and INH pin enabling <100 μA standby current. Protection features-feedback disconnection detection, output overvoltage protection (OVP at ~1.3× V_FB), zero-load burst mode, and thermal shutdown at 150 °C-are fully exercised on this board.

Key Specifications

Availability

EVAL5973AD is available at Aetrix Electronics and suitable for industrial DC-DC converter development, automotive infotainment power supply validation, and networking equipment auxiliary rail design requiring stable component supply and documented reference implementation.

Supply support for EVAL5973AD 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer applications.

The EVAL5973AD belongs to ST's dedicated evaluation board portfolio for its L597x series of monolithic step-down regulators, engineered to accelerate design-in of high-efficiency, thermally robust DC-DC solutions for space-constrained 5 V and 12 V bus systems.

FAQ

What input voltage range is supported on the EVAL5973AD board?

The EVAL5973AD board supports 4 V to 25 V DC input, as defined by the voltage ratings of its input capacitor (C1 = 10 μF/25 V ceramic) and output capacitor (C2 = 330 μF/6.3 V POSCAP). Exceeding 25 V risks capacitor failure and is outside the validated operating envelope per ST's application circuit documentation.

Can the EVAL5973AD be used to evaluate output voltages other than 3.3 V?

Yes-the board is configured for 3.3 V by default using R1=5.6 kΩ and R2=3.3 kΩ, but the feedback divider is accessible and reworkable. Output voltage is set by V_OUT = 1.235 V × (1 + R1/R2), allowing adjustment from 1.235 V to 35 V per the L5973AD datasheet, provided external components meet voltage and power ratings.

Does the EVAL5973AD support synchronization with external clock sources?

Yes-the board exposes the SYNC pin (Pin 2 of L5973AD) and includes no pull-up/pull-down, enabling direct connection to external 500+ kHz clock signals. When driven externally, the L5973AD synchronizes its internal oscillator, reducing beat frequencies and improving EMI predictability in multi-rail systems.

Is thermal measurement capability built into the EVAL5973AD board?

No dedicated thermal sensor is integrated, but the board layout follows ST's recommended copper pour and thermal pad soldering guidelines for the HSOP8 package. Engineers can directly measure case temperature near the exposed pad or use infrared imaging to correlate with the junction-to-ambient thermal resistance (R_thJA ≈ 40 °C/W) documented in the L5973AD datasheet.