STMicroelectronics STEVAL-ISA152V1

Overview

STEVAL-ISA152V1 from STMicroelectronics is an evaluation board for the L7987 61 V, 3 A step-down asynchronous switching regulator in HTSSOP16 package, delivering a fixed 3.3 V/3 A output from 4.5–60 V input, with 500 kHz switching frequency, 3.5 ms soft-start, and open-drain PGOOD signal. It implements VBIAS switch-over and pulse-skipping for high efficiency across load range and supports 180° out-of-phase synchronization.

For engineers reviewing the STEVAL-ISA152V1 datasheet, STEVAL-ISA152V1 pinout, STEVAL-ISA152V1 application, or STEVAL-ISA152V1 equivalent, this board enables rapid validation of industrial power supply designs requiring wide-input DC-DC conversion, precise enable/PGOOD sequencing, and multi-regulator synchronization capability.

Technical Context

The board implements the L7987 IC in a fully assembled, tested configuration with external components optimized for 3.3 V/3 A operation: 10 µH power inductor (L1), 47 µF output capacitor (C5), 4.7 µF input capacitors (C1, C2), and feedback resistors (R7=6.8 kΩ, R8=47 kΩ) setting V_OUT=3.3 V. The schematic includes SYNCH and FSW pins routed to test points for synchronization and frequency monitoring.

It leverages the L7987's integrated 61 V/3 A N-channel MOSFET, internal 250 kHz oscillator (externally adjustable up to 1.5 MHz), auto-recovery overcurrent and thermal protection, and VBIAS pin switch-over to reduce quiescent current at light loads-enabling >90% peak efficiency at mid-load under typical conditions.

Key Specifications

Availability

STEVAL-ISA152V1 is available at Aetrix Electronics and suitable for industrial control power supplies, railway signaling converters, and programmable logic controller (PLC) I/O module power stages requiring stable component supply, full regulatory documentation, and pre-validated thermal layout.

Supply support for STEVAL-ISA152V1 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, designing and manufacturing microcontrollers, power ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL (ST Evaluation) series, purpose-built to accelerate design-in of ST power management ICs by providing reference schematics, validated layouts, test reports, and application notes for immediate lab evaluation.

FAQ

What input voltage range does STEVAL-ISA152V1 support?

The board accepts 4.5 V to 60 V DC input, matching the L7987's rated operating range. This covers standard 12 V/24 V/48 V industrial buses and accommodates automotive load-dump events up to 60 V. Input filtering uses two 4.7 µF/100 V ceramic capacitors (C1, C2) and a 100 nF bypass (C7).

Can the output voltage be adjusted?

Yes - the board is configured for 3.3 V using R7 (6.8 kΩ) and R8 (47 kΩ), but the L7987 supports adjustable outputs from 0.8 V via external resistor divider on FB pin. To change V_OUT, replace R7/R8 with values satisfying V_OUT = 0.8 V × (1 + R8/R7).

Does STEVAL-ISA152V1 support synchronization with other regulators?

Yes - the SYNCH pin (U1 Pin 7) accepts external clock signals, and two L7987-based boards can be synchronized 180° out-of-phase via FSW-to-SYNCH routing. This reduces total input RMS current ripple and eases input capacitor sizing in multi-rail systems.

What protections are implemented on this evaluation board?

The board inherits all L7987 protections: cycle-by-cycle overcurrent limiting (via ILIM pin), thermal shutdown (>150°C junction), and open-drain PGOOD with 100 ms delay. No additional discrete protection circuitry is added - fault recovery is fully automatic per L7987 internal logic.