Microchip Technology AT97SC3205T-H3M4C20B

Overview

AT97SC3205T-H3M4C20B 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 supports industrial temperature range (-40°C to +85°C) in 32-pad QFN package.

For engineers reviewing the AT97SC3205T-H3M4C20B datasheet, AT97SC3205T-H3M4C20B pinout, AT97SC3205T-H3M4C20B application, or AT97SC3205T-H3M4C20B equivalent, this page delivers verified technical context, validated pin functions, real-world use scenarios in secure boot and firmware attestation, and confirmed alternative TPM modules for embedded system design.

Technical Context

The AT97SC3205T-H3M4C20B implements the full TCG TPM 1.2 specification with on-chip RSA key generation, HMAC authentication, and SHA-1 hashing. Its hardware crypto engine offloads cryptographic operations from host processors while internal EEPROM securely stores RSA keys.

It uses a dedicated I²C interface (SM_DAT/SM_CLK) with configurable pull-up requirements (800Ω on SM_DAT, 1.5kΩ on SM_CLK for 400kHz operation) and includes physical presence detection (PP/GPIO), low-power sleep recovery (TWI_Wakeup#), and tamper-aware GPIOs (TestBI/GPIO/XTAMPER).

Key Specifications

Pinout & Package

AT97SC3205T-H3M4C20B is supplied in a 32-pad Very Thin QFN (32M3) package with exposed thermal pad internally connected to GND. The package measures 4.0×4.0×0.90 mm with 0.40 mm pitch and supports reflow soldering per JEDEC MO-220 standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Infineon SLB9670 and Nuvoton NPCT750YAXX, the AT97SC3205T-H3M4C20B offers verified TPM 1.2 compliance with hardware-enforced physical presence and tamper sensing - critical for industrial deployments requiring backward compatibility and robust physical security controls.

Availability

AT97SC3205T-H3M4C20B is available at Aetrix Electronics and suitable for secure boot, firmware attestation, and hardware-based disk encryption applications requiring stable component supply and long-term industrial temperature support.

Supply support for AT97SC3205T-H3M4C20B 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 systems.

The AT97SC3205T product line delivers turnkey TPM 1.2 modules targeting industrial and enterprise embedded platforms requiring certified cryptographic acceleration, secure key storage, and hardware-rooted trust anchors.

FAQ

What is the primary security standard compliance of the AT97SC3205T-H3M4C20B?

The AT97SC3205T-H3M4C20B is fully compliant with the Trusted Computing Group (TCG) Trusted Platform Module (TPM) Version 1.2 Specification. It implements all mandatory TCG 1.2 commands and protocols, including PCR extension, key sealing/unsealing, and platform authentication. This compliance enables interoperability with Windows BitLocker, Linux tpm-tools, and enterprise security frameworks requiring TPM 1.2 root-of-trust functionality.

Does the AT97SC3205T-H3M4C20B support TPM 2.0 features such as SHA-256 or ECC?

No, the AT97SC3205T-H3M4C20B implements only TPM 1.2 functionality and does not support TPM 2.0 features including SHA-256 hashing, elliptic curve cryptography (ECC), or extended PCR capabilities. Its cryptographic engines are limited to SHA-1, RSA-1024/2048, AES-128, and HMAC-SHA1 as defined in the TCG 1.2 specification. For TPM 2.0 requirements, alternative modules like Infineon SLB9670 must be evaluated.

How is physical presence enforced on the AT97SC3205T-H3M4C20B?

Physical presence is enforced via the PP/GPIO pin on the AT97SC3205T-H3M4C20B, which has an internal pull-down resistor and serves as an active-high hardware presence indicator. When asserted high, it authorizes privileged operations such as TPM_Clear, TPM_OwnerSetDisable, or TPM_TakeOwnership. The AT97SC3205T-H3M4C20B requires this signal to be driven externally - typically by a front-panel button or system controller - ensuring human intervention before security-critical actions.

What are the I²C interface requirements for reliable 400kHz operation of the AT97SC3205T-H3M4C20B?

For reliable 400kHz Fast Mode I²C operation, the AT97SC3205T-H3M4C20B requires an 800Ω pull-up resistor on SM_DAT and a 1.5kΩ pull-up on SM_CLK, with both signals maintained near 50% duty cycle. Bus capacitance must remain below 400pF, and VCC decoupling must include 2200–4700pF capacitors placed within 5mm of each VCC pin and a 0.1μF bulk capacitor within 10mm of the device. These constraints ensure timing margin compliance per I²C specification.

Can the AT97SC3205T-H3M4C20B operate in low-power modes, and how is wake-up handled?

Yes, the AT97SC3205T-H3M4C20B automatically enters low-power sleep mode when idle. Recovery requires pulsing both TWI_Wakeup# pins low in sequence - a dual-signal mechanism preventing accidental wake-up. This behavior is triggered only by the Atmel-specific TPM_DeepSleep command; standard I²C activity does not induce deep sleep. The wake-up latency is deterministic and documented in the Atmel TPM Specific Commands guide.