Microchip Technology AT97SC3205T-G3M4B-20

Overview

AT97SC3205T-G3M4B-20 from Microchip (acquired 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 targets secure boot, platform authentication, and key management in embedded systems.

For engineers reviewing the AT97SC3205T-G3M4B-20 datasheet, AT97SC3205T-G3M4B-20 pinout, AT97SC3205T-G3M4B-20 application, or AT97SC3205T-G3M4B-20 equivalent, this page delivers verified electrical specs, validated I²C timing constraints, confirmed package dimensions (32-pin QFN), real-world GPIO mapping (e.g., PP/GPIO, GPIO-Express-00), and FIPS-140-2 module certification scope - all critical for TPM integration into industrial control, medical devices, and network infrastructure.

Technical Context

The AT97SC3205T-G3M4B-20 implements the full TCG TPM 1.2 specification stack in silicon, including command parsing, session management, and cryptographic state handling. Its internal AVR CPU executes firmware that enforces strict physical and logical security boundaries between host-accessible registers and protected key storage.

It supports dual I²C modes (100 kHz standard / 400 kHz fast), requires precise SM_DAT/SM_CLK pull-up values (800 Ω and 1.5 kΩ respectively) for stable high-speed operation, and uses dedicated pins (TWI_Wakeup#, PIRQ#) for low-power sleep recovery and interrupt signaling - confirming its role as a system-level security co-processor rather than a general-purpose MCU.

Key Specifications

Pinout & Package

AT97SC3205T-G3M4B-20 is packaged in a 32-pad Very Thin QFN (32M3) with exposed GND center pad. Pinout is validated per Atmel-8883AS-TPM-AT97SC3205T-Datasheet-Summary_022014, Table 1-2 and Figure 1-1.

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 NPCT750KBX1G, the AT97SC3205T-G3M4B-20 uniquely combines FIPS-140-2 Level 2 certification, GPIO-Express-00 NV-index binding, and dual-pin TWI_Wakeup# for robust low-power control - making it optimal for industrial systems needing certified security with field-upgradeable configuration persistence.

Availability

AT97SC3205T-G3M4B-20 is available at Aetrix Electronics and suitable for secure boot authentication, platform integrity attestation, and hardware-based key management requiring stable component supply across long-lifecycle industrial programs.

Supply support for AT97SC3205T-G3M4B-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 full support for legacy Atmel security products. The company specializes in microcontrollers, analog, and security solutions for industrial, automotive, and communications markets.

The AT97SC3205T-G3M4B-20 belongs to Atmel's TPM product line, designed specifically for embedded systems requiring TCG-compliant hardware-rooted trust, cryptographic acceleration, and FIPS-certified operation in harsh environments.

FAQ

What is the primary security certification level for the AT97SC3205T-G3M4B-20?

The AT97SC3205T-G3M4B-20 is FIPS-140-2 Level 2 certified as a complete module, covering its hardware random number generator (RNG), HMAC, AES, SHA, and RSA cryptographic engines. This certification validates its suitability for U.S. federal and regulated industry applications requiring auditable cryptographic assurance. The AT97SC3205T-G3M4B-20 achieves this through physical security mechanisms, role-based access control, and tamper-evident design - all verified under the FIPS validation process.

Does the AT97SC3205T-G3M4B-20 support both TPM 1.2 and TPM 2.0 specifications?

No, the AT97SC3205T-G3M4B-20 implements only the Trusted Computing Group (TCG) TPM 1.2 specification and does not support TPM 2.0 commands, algorithms, or structures. Its firmware, register map, and cryptographic engine configuration are fixed to TPM 1.2 requirements. For TPM 2.0 compatibility, users must select newer-generation modules such as Infineon SLB9670 or STMicroelectronics ST33TPHF2ES.

What are the exact I²C pull-up resistor values recommended for stable 400 kHz operation of the AT97SC3205T-G3M4B-20?

For reliable 400 kHz Fast Mode I²C operation, the AT97SC3205T-G3M4B-20 requires an 800 Ω pull-up resistor on the SM_DAT line and a 1.5 kΩ pull-up on the SM_CLK line. These values are empirically validated in the Atmel datasheet summary to ensure signal rise time compliance and noise margin - deviating significantly may cause communication timeouts or CRC errors during TPM command sequences.

How is the GPIO-Express-00 pin functionally distinct from the standard GPIO pin on the AT97SC3205T-G3M4B-20?

The GPIO-Express-00 pin on the AT97SC3205T-G3M4B-20 is mapped to TPM_NV_INDEX_GPIO_00, enabling persistent storage of its state in non-volatile memory - unlike the standard GPIO, which retains no state across resets. It features an internal pull-up and serves as XOR chain output during I/O test mode. This makes AT97SC3205T-G3M4B-20 ideal for storing secure configuration flags or hardware lock states that must survive power cycles.

Can the AT97SC3205T-G3M4B-20 enter and exit low-power sleep autonomously, or does it require host coordination?

The AT97SC3205T-G3M4B-20 enters low-power sleep automatically when idle, but exiting requires explicit host action: two dedicated pins (TWI_Wakeup# and PIRQ#) must both be pulsed active-low in sequence to recover from DeepSleep mode. This dual-signal requirement prevents accidental wake events and ensures deterministic power-state transitions - a design feature confirmed in the Atmel TPM Specific Commands document referenced in the datasheet.