STMicroelectronics STEVAL-ISA189V1

Overview

STEVAL-ISA189V1 from STMicroelectronics is an evaluation board for the A6986F5V 38 V, 1.5 A synchronous step-down switching regulator, designed for automotive battery-powered systems with cold-crank tolerance (100% duty cycle), 4–38 V input range, fixed 5 V output, and dual operating modes (LCM/LNM). It supports synchronization, adjustable soft-start, output voltage sequencing, and embedded supervisor functionality.

For engineers reviewing the STEVAL-ISA189V1 datasheet, STEVAL-ISA189V1 pinout, STEVAL-ISA189V1 application, or STEVAL-ISA189V1 equivalent, this board enables rapid validation of A6986F5V performance in automotive body electronics, infotainment power rails, and start-stop system auxiliary supplies under real-world voltage transients and light-load efficiency constraints.

Technical Context

The board implements the A6986F5V IC in peak current mode control architecture with integrated high-side (R_DS(on) = 180 mΩ) and low-side (R_DS(on) = 150 mΩ) MOSFETs, enabling 1.5 A DC output at up to 2 MHz switching frequency. It features programmable ISKIP current, adjustable f_SW (250 kHz–2 MHz), and dual-mode operation: low-consumption mode (30 μA I_Q) for parked-car applications and low-noise mode (forced PWM) for EMI-sensitive infotainment.

Hardware-level protections include overvoltage protection, thermal shutdown, internal current limiting, and output voltage supervisor. The default configuration uses LCM, 500 kHz f_SW, high ISKIP, and switchover enabled - all configurable via jumpers and resistors per schematic.

Key Specifications

Availability

STEVAL-ISA189V1 is available at Aetrix Electronics and suitable for automotive body electronics, infotainment power supply design, start-stop system auxiliary rails, and cold-crank tolerant ECU development requiring stable component supply and validated reference layouts.

Supply support for STEVAL-ISA189V1 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, Switzerland, specializing in automotive-grade, industrial, and power management solutions with broad IP portfolio and AEC-Q100 qualified product lines.

The STEVAL-ISA189V1 belongs to ST's automotive evaluation board family, developed specifically to accelerate qualification and integration of A6986F5V into battery-supplied vehicle systems demanding robustness against load-dump, cold-crank, and ultra-low quiescent current.

FAQ

What is the primary function of the STEVAL-ISA189V1 evaluation board?

The STEVAL-ISA189V1 is a fully assembled and tested evaluation platform for the A6986F5V synchronous buck regulator. Its purpose is to enable functional verification, performance characterization, and design-in support for automotive applications-specifically validating efficiency, transient response, mode switching (LCM/LNM), and protection behavior across 4–38 V input conditions and 0–1.5 A load range.

Can the output voltage be adjusted to values other than 5 V?

No-the STEVAL-ISA189V1 is configured for fixed 5 V output using the A6986F5V variant, which integrates the feedback divider. While the underlying A6986F5V IC does not support adjustable output, ST offers the pin-compatible A6986H5V (5 V) and A6986Hxx variants with different fixed outputs; however, this board's layout and component selection are optimized exclusively for 5 V operation.

How is synchronization implemented on this board?

Synchronization is implemented via the SYNCH pin (U1 Pin 4) connected to test point TP3. The board accepts an external clock signal (250 kHz–2 MHz) to align switching frequency with system timing requirements-critical for reducing beat frequencies in multi-rail automotive systems. Pull-up resistor R11 (10 Ω) and capacitor C8 (150 pF) provide noise filtering and impedance matching per A6986F5V datasheet recommendations.

Does the board support both low-consumption mode (LCM) and low-noise mode (LNM)?

Yes-mode selection is controlled by the SS/INH pin (U1 Pin 3) via test point TP1. LCM is active by default (30 μA I_Q); applying logic high to TP1 forces LNM (forced PWM, no frequency skipping), eliminating audible noise and spectral sidebands required for infotainment audio subsystems. Both modes retain full protection functionality and output regulation accuracy.