Microchip Technology AT97SC3205T-G3M46-20

Overview

AT97SC3205T-G3M46-20 from 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 (400kHz Fast Mode) and targets secure boot, platform integrity verification, and key management in embedded computing systems.

For engineers reviewing the AT97SC3205T-G3M46-20 datasheet, AT97SC3205T-G3M46-20 pinout, AT97SC3205T-G3M46-20 application, or AT97SC3205T-G3M46-20 equivalent, this page delivers verified package mapping (32-pin QFN), confirmed I²C timing constraints, TPM-specific GPIO assignments (PP/GPIO, GPIO-Express-00), low-power sleep recovery via TWI_Wakeup#, and FIPS-140-2 module certification scope.

Technical Context

The AT97SC3205T-G3M46-20 implements the full TCG TPM 1.2 specification stack in silicon, including command parsing, cryptographic acceleration, and secure non-volatile key storage. Its AVR CPU executes firmware that enforces strict physical and logical security boundaries between host-accessible registers and protected crypto operations.

It uses dedicated hardware blocks for SHA-1, HMAC, AES-128, RSA-2048, and a FIPS-140-2 validated pseudo-random number generator. The device supports both Standard (100kHz) and Fast (400kHz) I²C modes with precise SM_DAT/SM_CLK pull-up recommendations (800Ω and 1.5kΩ respectively) to ensure reliable communication under noise-sensitive conditions.

Key Specifications

Pinout & Package

AT97SC3205T-G3M46-20 is packaged in a 32-pad Very Thin QFN (32M3) with 4.0×4.0 mm body, 0.40 mm pitch, and exposed GND center pad internally connected to system ground. Pin assignment follows TCG-compliant TPM I/O mapping with dedicated physical presence (PP/GPIO), express GPIO (GPIO-Express-00), tamper detection (TestBI/GPIO/XTAMPER), and low-power wakeup (TWI_Wakeup#) signals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Infineon SLB9665TT2.0 and NXP PCF5102A, the AT97SC3205T-G3M46-20 uniquely combines I²C interface, on-chip AVR CPU, FIPS-140-2 certified crypto engines, and 2066-byte user NV storage - making it optimal for resource-constrained embedded systems requiring drop-in TPM 1.2 functionality with minimal host software overhead.

Availability

AT97SC3205T-G3M46-20 is available at Aetrix Electronics and suitable for server platform integrity verification, industrial control secure boot, and embedded edge gateway security requiring stable component supply and long-term lifecycle support.

Supply support for AT97SC3205T-G3M46-20 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

Atmel Corporation, now part of Microchip Technology, is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and security ICs for embedded applications.

The AT97SC3205T product line delivers certified TPM 1.2 functionality in single-chip form for integration into PCs, servers, industrial controllers, and medical devices where hardware-rooted trust and cryptographic assurance are mandatory.

FAQ

What is the primary interface protocol supported by the AT97SC3205T-G3M46-20?

The AT97SC3205T-G3M46-20 supports only the I²C interface, operating at 100kHz Standard Mode or 400kHz Fast Mode. It does not support SPI or LPC interfaces. Pull-up resistors of 800Ω on SM_DAT and 1.5kΩ on SM_CLK are recommended for reliable 400kHz operation, and the SM_CLK duty cycle should be as close to 50% as possible to maximize timing margin. This interface design simplifies integration into microcontroller-based systems with limited peripheral options.

Does the AT97SC3205T-G3M46-20 include on-chip non-volatile storage for user data?

Yes, the AT97SC3205T-G3M46-20 provides 2066 bytes of dedicated NV storage space for user-defined data, separate from standard TPM NV indices. This space is implemented in internal EEPROM and persists across power cycles. It is accessible via TCG-compliant commands and intended for storing device-specific credentials, configuration policies, or custom keys - all protected by the same FIPS-140-2 certified security boundary applied to RSA key storage.

How is physical presence asserted on the AT97SC3205T-G3M46-20?

Physical presence is asserted via the PP/GPIO pin on the AT97SC3205T-G3M46-20, which functions as a hardware indicator with internal pull-down resistance. When driven high by an external switch or GPIO, it signals authorized physical access to enable privileged TPM operations such as clearing ownership or changing platform configuration. The pin defaults to GPIO input mode and must remain floating or pulled low when unused, per the datasheet guidance.

What certifications apply to the cryptographic engines inside the AT97SC3205T-G3M46-20?

The AT97SC3205T-G3M46-20 is certified as a FIPS-140-2 Level 2 cryptographic module, covering its hardware random number generator (RNG), HMAC, AES-128, SHA-1, and RSA-2048 engines. This certification validates implementation correctness, resistance to physical attack, and operational integrity under defined environmental conditions. The RNG specifically meets FIPS 140-2 Annex C requirements for entropy sources and deterministic random bit generation.

Can the AT97SC3205T-G3M46-20 enter a low-power state, and how is it recovered?

Yes, the AT97SC3205T-G3M46-20 automatically enters low-power sleep mode when idle. Recovery requires pulsing both TWI_Wakeup# pins (pins 7 and 22 in TSSOP, or corresponding terminals in QFN) active-low simultaneously - a unique dual-signal requirement to prevent spurious wakeups. This mechanism is triggered by the TPM_DeepSleep command and documented in the Atmel TPM Specific Commands reference. The AT97SC3205T-G3M46-20 does not support SPI-based wakeup or autonomous timer-based resume.