STMicroelectronics STM6524ALARDL6F

Overview

STM6524ALARDL6F from STMicroelectronics is a 6-pin Smart Reset™ supervisor IC with dual active-low push-button inputs (SR0, SR1), factory-programmed 6.0 s Smart Reset™ setup delay (tSRC), open-drain active-low reset output (RST), and no fixed reset pulse width (push-button controlled). It operates from 1.65 V to 5.5 V, draws only 1.5 µA typical supply current, and targets portable electronics requiring glitch-immune, delayed manual reset functionality.

For engineers reviewing the STM6524ALARDL6F datasheet, STM6524ALARDL6F pinout, STM6524ALARDL6F application, or STM6524ALARDL6F equivalent, this device delivers precise tSRC timing control, test-mode entry via overvoltage on SR0, undervoltage immunity down to 1.0 V, and UDFN6 footprint compatibility for space-constrained designs.

Technical Context

The STM6524ALARDL6F implements dual-input synchronous logic: both SR0 and SR1 must be held low for the full factory-set tSRC = 6.0 s (typ.) before asserting RST. Its reset output remains asserted only while at least one input stays low-no minimum pulse width is guaranteed, enabling direct push-button release control of reset duration.

Test mode activation occurs when SR0 voltage exceeds VCC + 0.9 V (min.), triggering a shortened 21 ms tSRC-SHORT timer and visual feedback via RST assertion. The device guarantees valid deasserted RST levels down to VCC = 1.0 V and ignores inputs below 1.575 V typ., providing robust undervoltage hysteresis.

Key Specifications

Pinout & Package

UDFN6 package: 1.6 mm × 1.3 mm × 0.55 mm body height, 0.40 mm pin pitch, exposed thermal pad (not electrically connected), RoHS-compliant ECOPACK®2 finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Smart Reset™ supervisor applications.

Compared with STM6524ALARDL6F, ALABDL6F adds guaranteed reset pulse width at the cost of push-button responsiveness, while APARDL6F extends tSRC for stricter reset qualification-both retain identical UDFN6 footprint and operating voltage range.

Availability

STM6524ALARDL6F is available at Aetrix Electronics and suitable for mobile phones, e-readers, and portable navigation devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM6524ALARDL6F 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The STM65xx Smart Reset™ family targets portable electronics needing reliable, low-power, push-button-initiated system recovery-emphasizing timing precision, small footprint, and robust noise immunity over traditional reset ICs.

FAQ

What is the function of Pin 4 (NC) on the STM6524ALARDL6F?

Pin 4 is internally not connected (NC) and not bonded. The datasheet explicitly requires it to be connected to VSS (ground) on the PCB to ensure mechanical stability and optimal thermal performance of the UDFN6 package. Leaving it floating may compromise solder joint reliability and thermal dissipation.

Does the STM6524ALARDL6F provide power-on reset (POR) functionality?

No. The STM6524ALARDL6F does not include a power-on reset circuit. It relies entirely on user-initiated Smart Reset™ inputs (SR0/SR1) and has no internal voltage monitoring threshold for automatic reset at power-up. System POR must be handled separately by the host microcontroller or another supervisor IC.

How is test mode triggered and verified on the STM6524ALARDL6F?

Test mode is triggered by applying ≥ VCC + 0.9 V to SR0 (Pin 5), causing RST (Pin 3) to assert immediately. This provides visual feedback confirming entry. The device then uses shortened tSRC-SHORT = 21 ms (typ.) instead of the full 6.0 s delay, enabling rapid functional verification without full button-hold cycles.

Can the STM6524ALARDL6F drive a microcontroller reset pin directly?

Yes, but only with an external pull-up resistor. The RST output is open-drain and active-low; it cannot source current. A typical 10 kΩ pull-up to the microcontroller's VDD rail ensures proper logic-high level when RST is inactive, and strong logic-low assertion when active-matching standard reset pin requirements.