STMicroelectronics ST25DV02K-W2R8S3

Overview

ST25DV02K-W2R8S3 from STMicroelectronics is a dynamic NFC/RFID tag IC compliant with ISO/IEC 15693 and NFC Forum Type 5, integrating two independent PWM outputs (PWM1 and PWM2), 2-Kbit EEPROM, on-chip 28.5 pF tuning capacitance, and TruST25 digital signature authentication. It operates with contactless RF power and separately powered PWM interface (1.8–5.5 V), enabling real-time live update of PWM parameters via RF field while maintaining PWM output stability during RF activity - used in smart sensors, industrial calibration tags, and battery-free human-machine interface modules.

For engineers reviewing the ST25DV02K-W2R8S3 datasheet, ST25DV02K-W2R8S3 pinout, ST25DV02K-W2R8S3 application, or ST25DV02K-W2R8S3 equivalent, key selection considerations include dual-PWM timing resolution (62.5 ns min pulse width step), independent VCC-powered PWM drive (up to 4 mA per output), RF/PWM coexistence modes, password-protected memory segmentation (four independent areas), and ECOPACK2-compliant SO8N/TSSOP8 packaging.

Technical Context

The device implements two fully independent PWM generators, each configurable via dedicated 32-bit control registers (PWM1_CTRL at block F8h, PWM2_CTRL at F9h), supporting period values from 512–32767 × PWMres (32–2048 µs) and pulse width values from 0–32767 × PWMres - yielding frequency range 488 Hz–31.25 kHz with bit-resolution scaling (9–15 bits). Internal oscillator eliminates need for external clock source.

RF interface uses ISO/IEC 15693 analog front-end with integrated 28.5 pF tuning capacitance and supports all sub-carrier modes (6.4 µs/1.6 µs), data rates (26 kbps/53 kbps), and command sets (Read Single/Multiple Block, Write Single Block, Lock). PWM and RF operate autonomously: RF functions without VCC; PWM functions without RF field - boot priority logic ensures deterministic initialization sequencing.

Key Specifications

Pinout & Package

ST25DV02K-W2R8S3 is available in SO8N and TSSOP8 packages (ECOPACK2, RoHS-compliant), both with identical pin mapping and 1.27 mm pitch (SO8N) / 0.65 mm pitch (TSSOP8).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dynamic NFC tag with PWM output applications.

Compared with ST25DV02KC-W2, the ST25DV02K-W2R8S3 offers lower thermal rating but identical feature set and footprint; compared with NXH3670UK, it provides stronger security, dual-PWM flexibility, and broader voltage range - making it optimal for secure, multi-actuator industrial tagging.

Availability

ST25DV02K-W2R8S3 is available at Aetrix Electronics and suitable for smart sensor calibration, NFC-enabled lighting control, and secure medical device authentication requiring stable component supply across long-lifecycle industrial programs.

Supply support for ST25DV02K-W2R8S3 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 microcontrollers, power management ICs, sensors, and connectivity solutions for industrial, automotive, and consumer markets.

This device belongs to the ST25 Dynamic NFC tag product line, engineered specifically for battery-free or ultra-low-power systems requiring secure wireless configuration and local analog actuation - bridging RFID identification with real-time embedded control.

FAQ

What is the maximum PWM frequency achievable with ST25DV02K-W2R8S3, and how is it determined?

The maximum PWM frequency is 31.25 kHz, achieved when PWMx_PERIOD = 512 and PWM resolution (PWMres) = 62.5 ns. This value is fixed by the internal oscillator and cannot be adjusted externally. At this frequency, the pulse width resolution is limited to 9 bits (0–511 steps), meaning minimum controllable duty cycle increment is ~0.2%. The relationship Period = PWMx_PERIOD × 62.5 ns holds across the entire range.

Can ST25DV02K-W2R8S3 operate with only RF power, or does VCC always need to be supplied for PWM functionality?

VCC must be supplied for any PWM output to function - the RF interface operates independently and can read/write EEPROM or authenticate without VCC, but PWM1 and PWM2 require VCC (1.8–5.5 V) to power their output drivers and logic. When VCC is absent, PWM pins remain in high-impedance state regardless of RF commands. This separation enables hybrid energy harvesting designs where RF handles configuration and VCC powers actuation.

How does the TruST25 digital signature mechanism work, and what cryptographic primitives does it use?

TruST25 implements hardware-accelerated ECDSA (Elliptic Curve Digital Signature Algorithm) using NIST P-256 curve. Each device contains a unique, factory-programmed private key stored in tamper-resistant memory. During authentication, the reader sends a challenge; the IC signs it with its private key, and the reader verifies using the public key (stored in UID area or provisioned externally). No software stack or external crypto processor is required - signature generation and verification occur entirely within the IC's secure module.

Is ST25DV02K-W2R8S3 pin-compatible with ST25DV02K-W1, and what design changes are needed to migrate?

Yes - both share identical SO8N/TSSOP8 pinout and memory map; PWM2 is simply unused (HiZ) on W1. To migrate from W1 to W2R8S3, no PCB change is needed. Software must initialize and configure F9h (PWM2_CTRL) in addition to F8h, and enable PWM2_ENABLE bit. Coexistence settings in PWM_CFG (bits b3–b2, b6–b4) should be reviewed to ensure dual-PWM timing integrity during RF activity.