STMicroelectronics STM6524APARDL6F

Overview

STM6524APARDL6F from STMicroelectronics is a 6-pin Smart Reset™ supervisor IC designed for delayed, dual-button reset control in portable electronics. It features factory-programmed 7.5 s Smart Reset™ setup delay (tSRC), open-drain active-low reset output (RST), no fixed tREC pulse width (push-button controlled), operating voltage range 1.65 V to 5.5 V, and ultra-low 1.5 µA supply current. It enables reliable hard-reset initiation only after sustained button press-used in smartphones and e-readers to distinguish short interrupts from system recovery.

For engineers reviewing the STM6524APARDL6F datasheet, STM6524APARDL6F pinout, STM6524APARDL6F application, or STM6524APARDL6F equivalent, key selection criteria include tSRC programmability (7.5 s typ.), absence of tREC timing guarantee, UDFN6 package footprint (1.6 mm × 1.3 mm), dual active-low SR inputs with internal pull-up option, and undervoltage immunity down to 1.0 V.

Technical Context

The STM6524APARDL6F implements dual-input, edge- and level-sensitive Smart Reset™ logic: both SR0 and SR1 must be held low simultaneously for ≥7.5 s (tSRC) before asserting RST. Its test mode is triggered by overvoltage on SR0 (>VCC + 0.9 V), enabling rapid validation via shortened 21 ms tSRC-SHORT.

No power-on reset (POR) circuitry is integrated; reset assertion relies solely on user-initiated button hold duration. The RST output deasserts immediately upon release of either SR input-no minimum pulse width is enforced, making it suitable for applications requiring dynamic reset termination.

Key Specifications

Pinout & Package

UDFN6 package: 1.6 mm × 1.3 mm, 0.40 mm pitch, 0.55 mm height, ECOPACK®2 RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar delayed reset supervisor applications.

Compared with STM6524APARDL6F, the ALARDL6F offers faster reset initiation (6.0 s vs. 7.5 s), while AUARDL6F increases fault tolerance with extended 10.0 s hold requirement-both retain identical open-drain RST behavior and UDFN6 footprint for drop-in layout reuse.

Availability

STM6524APARDL6F is available at Aetrix Electronics and suitable for smartphone system recovery, e-reader hard reset, and portable navigation device recovery requiring stable component supply across high-volume consumer electronics programs.

Supply support for STM6524APARDL6F 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, delivering innovative silicon solutions for automotive, industrial, and consumer markets since 1987.

The STM65xx Smart Reset™ family was engineered specifically for portable electronics requiring robust, low-power, dual-button reset supervision with programmable delay-addressing reliability gaps in traditional POR-based reset schemes.

FAQ

Does STM6524APARDL6F provide power-on reset (POR) functionality?

No. The STM6524APARDL6F lacks internal POR circuitry. It asserts RST only in response to sustained dual-button press (≥7.5 s). System power-up reset must be handled externally-e.g., by MCU's internal POR or a separate supervisor IC. This design avoids redundant reset assertion during normal startup.

What is the purpose of the NC pin (Pin 4), and how should it be handled?

Pin 4 is internally unbonded and designated NC (No Connect). Per ST's layout guidance, it must be connected to VSS (ground) on the PCB. This ensures mechanical stability of the UDFN6 package during reflow and improves thermal dissipation and EMI performance-leaving it floating risks solder joint reliability and noise coupling.

Can the RST output drive a 3.3 V microcontroller reset pin directly?

Yes, but only with an external pull-up resistor. Since STM6524APARDL6F uses open-drain RST (no internal pull-up), a 10 kΩ pull-up to the target MCU's VDD (e.g., 3.3 V) is required to generate valid logic-high and logic-low levels. Without it, RST remains floating when inactive, risking undefined MCU behavior.

How does test mode activation work, and what happens once entered?

Test mode is activated by applying >VCC + 0.9 V to SR0 (Pin 5). Upon entry, RST asserts for 42 ms (tSRC-INI), then remains asserted while SR0 stays overvolted. During test mode, pressing both SR0 and SR1 together triggers a shortened 21 ms reset (tSRC-SHORT) instead of 7.5 s-enabling rapid functional verification without full delay wait.