Microchip Technology AT97SC3205T-H3M44-20

Overview

AT97SC3205T-H3M44-20 from Microchip Technology (formerly Atmel) is a TCG-compliant Trusted Platform Module implementing TPM 1.2 specification, featuring an integrated 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 targets secure boot and platform authentication in industrial embedded systems.

For engineers reviewing the AT97SC3205T-H3M44-20 datasheet, AT97SC3205T-H3M44-20 pinout, AT97SC3205T-H3M44-20 application, or AT97SC3205T-H3M44-20 equivalent, key selection criteria include TPM 1.2 compliance, I²C timing constraints (SM_DAT/SM_CLK pull-up recommendations), GPIO-Express-00 mapping to TPM_NV_INDEX_GPIO_00, low-power deep-sleep recovery via TWI_Wakeup#, and dual-package availability (28-pin TSSOP vs. 32-pad QFN).

Technical Context

The AT97SC3205T-H3M44-20 implements the full TCG TPM 1.2 stack in hardware, including command parsing, cryptographic acceleration, and secure key management. Its AVR CPU executes firmware that enforces strict physical security policies, while the FIPS-140-2 certified RNG feeds all cryptographic operations including RSA key generation and HMAC signing.

Communication occurs exclusively over I²C at 100 kHz (Standard Mode) or 400 kHz (Fast Mode), requiring precise SM_DAT (800 Ω pull-up) and SM_CLK (1.5 kΩ pull-up) termination for stable high-speed operation. The device supports hardware Physical Presence (PP/GPIO) and deep-sleep wake-up via dual TWI_Wakeup# pins - both must be pulsed low to exit low-power state.

Key Specifications

Pinout & Package

AT97SC3205T-H3M44-20 is offered in two RoHS-compliant packages: 28-pin Thin TSSOP (28X1, 4.4 × 9.7 mm body, 0.65 mm pitch) and 32-pad Very Thin QFN (32M3, 4.0 × 4.0 mm body, 0.40 mm pitch). Both support industrial temperature range (−40°C to +85°C) and require GND-connected substrate pad (QFN) or proper NC handling per package drawing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SLB9670 and NPCT750, AT97SC3205T-H3M44-20 offers optimal balance of TPM 1.2 compliance, 2066-byte NV storage, and I²C-only simplicity for industrial embedded hosts - especially where AVR-based firmware extensibility and GPIO-Express-00 integration are valued.

Availability

AT97SC3205T-H3M44-20 is available at Aetrix Electronics and suitable for secure boot authentication, platform integrity verification, hardware-based key vaulting, and remote attestation requiring stable component supply across industrial temperature ranges.

Supply support for AT97SC3205T-H3M44-20 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 its secure MCU and TPM product lines. The company specializes in microcontrollers, analog, FPGA, and security solutions for industrial, automotive, and communications markets.

AT97SC3205T-H3M44-20 belongs to Atmel's Trusted Platform Module family, designed specifically to deliver TCG-compliant hardware-rooted trust for embedded systems where firmware integrity, secure key storage, and remote attestation are mandatory.

FAQ

What is the primary compliance standard met by the AT97SC3205T-H3M44-20?

The AT97SC3205T-H3M44-20 is fully compliant with the Trusted Computing Group (TCG) Trusted Platform Module (TPM) Version 1.2 Specification. It implements the complete TPM 1.2 command set, including PCR operations, key management, and attestation functions. This compliance enables interoperability with industry-standard BIOS, OS drivers, and management software expecting TPM 1.2 behavior - a requirement for many industrial and enterprise security certifications.

Does the AT97SC3205T-H3M44-20 support TPM 2.0?

No, the AT97SC3205T-H3M44-20 does not support TPM 2.0. It is strictly compliant with TPM 1.2 as defined in the TCG specification. Its firmware, command parser, and cryptographic service layer are architected for TPM 1.2 primitives only. Migration to TPM 2.0 would require a hardware replacement such as the Infineon SLB9670 or Nuvoton NPCT750, which implement the updated protocol stack and algorithm agility.

How is low-power operation managed on the AT97SC3205T-H3M44-20?

The AT97SC3205T-H3M44-20 enters low-power sleep automatically when idle. To recover from deep-sleep mode, the host must pulse both TWI_Wakeup# pins (TSSOP pins 7 and 22, or QFN equivalents) low simultaneously. This dual-pin requirement prevents accidental wake-up and ensures deterministic power-state transitions. No additional control signals or register writes are needed - the behavior is hardwired in the silicon.

What are the I²C pull-up resistor requirements for reliable 400 kHz operation of the AT97SC3205T-H3M44-20?

For stable 400 kHz Fast Mode I²C operation, the AT97SC3205T-H3M44-20 requires an 800 Ω pull-up resistor on SM_DAT and a 1.5 kΩ pull-up on SM_CLK. These values were validated in Atmel's characterization lab; deviations may cause clock stretching or bus arbitration failures. Additionally, maintaining a ~50% SM_CLK duty cycle further improves timing margin, especially under voltage or temperature variation.

Can the GPIO-Express-00 pin on the AT97SC3205T-H3M44-20 be used as a general-purpose output?

GPIO-Express-00 on the AT97SC3205T-H3M44-20 is configured as an input by default and mapped to TPM_NV_INDEX_GPIO_00. While it has an internal pull-up and can be driven by firmware, its functionality is constrained by the TPM 1.2 specification - it cannot be freely reconfigured as a push-pull output. Its primary role is to reflect platform-specific state (e.g., chassis intrusion or button press) into the TPM's non-volatile index space for attestation purposes.