Microchip Technology AT97SC3205T-H3M46-20

Overview

AT97SC3205T-H3M46-20 from Microchip Technology (formerly Atmel) is a TCG-compliant Trusted Platform Module (TPM) 1.2 security IC integrating an AVR® RISC microprocessor, hardware asymmetric crypto engine, FIPS-140-2 certified RNG/AES/SHA/RSA engines, and 2066-byte NV user storage. It operates at 3.3V with I²C interface up to 400 kHz and supports industrial temperature range (−40°C to +85°C) in 32-pad QFN package.

For engineers reviewing the AT97SC3205T-H3M46-20 datasheet, AT97SC3205T-H3M46-20 pinout, AT97SC3205T-H3M46-20 application, or AT97SC3205T-H3M46-20 equivalent, key selection considerations include TPM 1.2 compliance, I²C timing constraints (SM_DAT/SM_CLK pull-up requirements), GPIO-Express-00 mapping to TPM_NV_INDEX_GPIO_00, low-power deep-sleep recovery via TWI_Wakeup#, and secure key storage architecture.

Technical Context

The AT97SC3205T-H3M46-20 implements the full TCG TPM 1.2 specification stack in hardware, including command parsing, authorization logic, and cryptographic acceleration. Its AVR CPU executes firmware that enforces strict physical security boundaries between volatile SRAM, EEPROM-stored RSA keys, and FIPS-140-2 validated crypto primitives.

Communication occurs exclusively over a two-wire I²C interface (SM_DAT/SM_CLK) supporting both Standard (100 kHz) and Fast Mode (400 kHz); timing stability requires precise 50% duty cycle on SM_CLK and verified pull-up values (800 Ω on SM_DAT, 1.5 kΩ on SM_CLK). The device enters automatic low-power sleep when idle and recovers only upon dual active-low assertion of TWI_Wakeup# pins.

Key Specifications

Pinout & Package

AT97SC3205T-H3M46-20 uses the 32-pad Very Thin QFN (32M3) package: 4.0 × 4.0 mm body, 0.40 mm pitch, exposed center thermal pad internally connected to GND. Pinout conforms to Atmel's documented 32-pin QFN configuration with dedicated I²C, GPIO, reset, interrupt, and test signals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TPM 1.2 security applications.

Compared with SLB9665TT2.0 and NPCT750KBX1RX, the AT97SC3205T-H3M46-20 uniquely combines I²C interface, FIPS-140-2 module certification, and pre-mapped GPIO-Express-00 for out-of-box TPM_NV_INDEX support - reducing firmware development effort and accelerating compliance validation.

Availability

AT97SC3205T-H3M46-20 is available at Aetrix Electronics and suitable for server platform authentication, industrial control system integrity, and medical device data integrity requiring stable component supply and long-term lifecycle assurance.

Supply support for AT97SC3205T-H3M46-20 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

Microchip Technology acquired Atmel in 2016 and maintains legacy Atmel security product lines including TPM modules. The company specializes in microcontrollers, analog, FPGA, and security solutions for industrial, automotive, and communications markets.

The AT97SC3205T product line delivers turnkey TPM 1.2 compliance for embedded systems needing hardware-rooted trust, with design focus on secure boot, remote attestation, and protected key storage in resource-constrained platforms.

FAQ

What is the primary interface protocol supported by the AT97SC3205T-H3M46-20?

The AT97SC3205T-H3M46-20 supports only the I²C interface (SM_DAT and SM_CLK pins) operating at 100 kHz Standard Mode or 400 kHz Fast Mode. It does not support SPI, UART, or LPC interfaces. Pull-up resistor values of 800 Ω on SM_DAT and 1.5 kΩ on SM_CLK are validated for stable 400 kHz operation, and SM_CLK duty cycle should be as close to 50% as possible to avoid communication timeouts.

Does the AT97SC3205T-H3M46-20 include FIPS-140-2 certification, and what components does it cover?

Yes, the AT97SC3205T-H3M46-20 is a FIPS-140-2 Level 2 certified module. Certification covers the integrated hardware random number generator (RNG), HMAC, AES-128, SHA-1, and RSA cryptographic engines - all implemented within the same silicon die. This certification applies to the complete module, not individual blocks, and is documented in the official NIST certificate listing for this part number.

How is the 2066-byte NV storage in the AT97SC3205T-H3M46-20 accessed and secured?

The AT97SC3205T-H3M46-20 provides 2066 bytes of user-defined non-volatile storage accessible via standard TCG TPM 1.2 commands (e.g., TPM_NV_DefineSpace, TPM_NV_Write). Each NV index is protected by authorization policies (e.g., password, physical presence), and writes are subject to TPM-locality and session-based HMAC validation. Storage resides in dedicated EEPROM separate from RSA key storage and persists across power cycles.

What is the function of the GPIO-Express-00 pin on the AT97SC3205T-H3M46-20, and how is it configured?

The GPIO-Express-00 pin on the AT97SC3205T-H3M46-20 is hard-mapped to TPM_NV_INDEX_GPIO_00 and provides persistent, TPM-secured GPIO state storage. It features an internal pull-up resistor and defaults to input mode. When used, it allows platform firmware to store and retrieve GPIO configuration or status in NV memory without custom index definition - simplifying integration for applications requiring tamper-evident hardware state tracking.

Can the AT97SC3205T-H3M46-20 enter and recover from low-power sleep autonomously?

Yes, the AT97SC3205T-H3M46-20 automatically enters low-power sleep when idle and remains in that state until explicitly woken. Recovery requires a synchronized dual active-low pulse on both TWI_Wakeup# pins - a hardware-level requirement enforced by the internal state machine. This mechanism prevents accidental wake events and ensures deterministic power-state transitions during deep-sleep use cases like extended standby in medical or industrial equipment.