STMicroelectronics STM1403CSNQ6F

Overview

STM1403CSNQ6F from STMicroelectronics is a FIPS-140 Level 3+ security supervisor IC for cryptographic module protection, featuring four high-impedance physical tamper inputs (TP1–TP4), over/under voltage detection (2.0 V / 4.2 V thresholds), and battery switchover with VCC-to-VBAT transition at ~2.4 V. It drives VOUT to ground during tamper events and provides open-drain SAL, RST, PFO, and BLD outputs - deployed in POS terminals and secure payment hardware.

For engineers reviewing the STM1403CSNQ6F datasheet, STM1403CSNQ6F pinout, STM1403CSNQ6F application, or STM1403CSNQ6F equivalent, key selection considerations include tamper response behavior (VOUT grounded on SAL), battery low detect threshold configurability (2.3 V / 2.5 V / 3.2 V), Vccsw logic state during alarm, and QFN16 3×3 mm package compatibility with secure PCB layout requirements.

Technical Context

The STM1403C implements dual-voltage monitoring: VINT (VCC or VBAT) is compared against VLV = 2.0 V (undervoltage) and VHV = 4.2 V (overvoltage) to trigger SAL. Tamper detection uses four independent inputs-TP1/TP3 (normally high, pulled low on intrusion) and TP2/TP4 (normally low, pulled high on intrusion)-with internal pull-up/pull-down options.

VOUT switching is controlled by VSW (~2.4 V): when VCC ≥ VSW, VOUT sourced from VCC; when VCC < VSW, VOUT sourced from VBAT. During SAL assertion, VOUT is actively driven to GND (distinguishing STM1403C from A/B variants), and Vccsw is forced high as a BATT ON indicator independent of VOUT state.

Key Specifications

Pinout & Package

STM1403CSNQ6F is housed in a secure, low-profile 16-pin QFN package (3 mm × 3 mm body, 0.5 mm pitch), optimized for anti-tampering PCB layouts with exposed thermal pad grounding and minimal trace exposure.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM1403CSNQ6F, the A variant preserves VOUT continuity for post-tamper diagnostics, while the B variant isolates VOUT entirely; the C variant's GND-driven VOUT provides strongest cryptographic key erasure assurance in SRAM-based systems.

Availability

STM1403CSNQ6F is available at Aetrix Electronics and suitable for POS terminal manufacturing, EMV payment device production, and government-issued ID card personalization systems requiring stable component supply and long-term lifecycle support.

Supply support for STM1403CSNQ6F 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 specializing in secure microcontrollers, power management, and automotive-grade ICs, with extensive expertise in cryptographic hardware design.

The STM1403 family targets FIPS-140 and EMVCo-compliant systems, delivering integrated tamper detection, voltage supervision, and battery switchover in a single secure QFN package.

FAQ

What is the VSW threshold for battery switchover?

The VSW threshold is approximately 2.4 V - when VCC falls below this value, the device automatically switches VOUT sourcing from VCC to VBAT. This value is fixed and not user-adjustable; it ensures reliable backup activation before main supply collapse, supporting standard 3 V lithium coin cells.

How does VOUT behavior differ between STM1403C and other variants during tamper?

During SAL assertion, STM1403C actively drives VOUT to GND - unlike STM1403A (VOUT remains ON) or STM1403B (VOUT goes High-Z). This GND forcing directly disables externally connected SRAM, enabling immediate cryptographic key erasure without additional circuitry.

Can TP1–TP4 be left unconnected?

No - unused tamper pins must be terminated: TP1/TP3 tied to VTPU (pin 6), TP2/TP4 tied to VSS. Floating these inputs risks false tamper alarms due to noise or leakage; the internal biasing is not sufficient for robust operation without proper external termination.

What is the purpose of the VTPU pin (pin 9) on STM1403C?

VTPU provides an internally switched version of VCC or VBAT - it follows the same source as VOUT and serves as a dedicated pull-up node for TP1/TP3 tamper circuits. Unlike STM1403A's VREF, it delivers no precision voltage but ensures consistent biasing across power domains during switchover.