STMicroelectronics ST763ACN

Overview

ST763ACN from STMicroelectronics is a fixed-output 3.3 V, 500 mA step-down DC-DC switching regulator with current-mode PWM control, operating from 3.3 V to 11 V input, 200 kHz typical switching frequency, and 90% typical efficiency-used in portable instrumentation and handheld computing power rails.

For engineers reviewing the ST763ACN datasheet, ST763ACN pinout, ST763ACN application, or ST763ACN equivalent, key selection criteria include guaranteed ±5% output voltage accuracy over line/load/temperature, 0.2 µA shutdown current, SO-8/DIP-8 package options, cycle-by-cycle current limiting, and under-voltage lockout at 2.7 V.

Technical Context

The ST763ACN implements current-mode PWM control for precise regulation and fast transient response, with internal P-channel MOSFET (R_DS(on) = 1 Ω) and integrated soft-start via external capacitor on SS pin. It uses voltage feedback sensing through OUT pin and external compensation via CC pin with 330 pF capacitor.

Under-voltage lockout activates below 2.7 V V_CC, and shutdown is active-low on SHDN pin. Reference voltage is 1.25 V (±50 ppm/°C drift), enabling accurate 3.3 V output via resistor divider-though output is fixed, not adjustable.

Key Specifications

Pinout & Package

ST763ACN is available in SO-8 (surface-mount) and DIP-8 (through-hole) packages. Both share identical pinout and electrical functionality.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2675-3.3 and TPS5430DDAR, ST763ACN offers lower BOM count and smaller footprint due to integrated P-MOSFET and fixed 3.3 V configuration-ideal for cost- and space-sensitive portable applications where 500 mA suffices.

Availability

ST763ACN is available at Aetrix Electronics and suitable for 5V-to-3.3V power conversion, handheld computing, and portable instrumentation requiring stable component supply and long-term industrial availability.

Supply support for ST763ACN 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The ST763A series targets low-to-moderate power portable electronics, delivering fixed-output buck regulation with minimal external components and robust protection-optimized for battery-operated 3.3 V system rails.

FAQ

What is the minimum input voltage required for ST763ACN to regulate 3.3 V output?

The ST763ACN requires a minimum input voltage of 3.3 V to maintain regulation, as specified in its absolute input range (3.3 V to 11 V). Below 3.3 V, under-voltage lockout engages, disabling switching. At exactly 3.3 V input, output remains regulated at 3.3 V only if load current is light and thermal conditions permit-design margin strongly recommends ≥3.6 V nominal input.

Can ST763ACN be used with an external synchronous rectifier?

No-ST763ACN integrates a P-channel MOSFET on the high-side switch (LX pin) but does not support synchronous rectification. The LX node drives an external Schottky diode (e.g., STPS330U), and the IC lacks control signals or timing logic for a second MOSFET. Synchronous operation would require a different controller architecture not present in this device.

Is the 3.3 V output adjustable using external resistors?

No-the ST763ACN provides a fixed 3.3 V output. Its feedback path connects the OUT pin directly to the regulated output; there is no access to the internal 1.25 V reference for external resistor-divider adjustment. Devices like ST763AB or ST763AD offer adjustable outputs, but ST763ACN is factory-trimmed and unmodifiable.

What thermal derating applies to ST763ACN in SO-8 package at 85°C ambient?

In SO-8 package, ST763ACN has R_thj-amb = 160 °C/W. At 85°C ambient and 500 mA load (P_D ≈ 0.5 W), junction temperature rises ~80°C above ambient-reaching ~165°C, exceeding the 150°C max storage limit. Derating to ≤300 mA at 85°C ambient is recommended to keep T_J ≤ 125°C for reliable operation.