6-Channel PWM-Output Fan RPM Controller

Versatile Fan RPM Controller Can Be Configured for Closed-Loop Control for Up to 6 Fans or Monitoring for Up to 12 Fans

Description

The MAX31790 controls the speeds of up to six fans using six independent PWM outputs. The desired fan speeds (or PWM duty cycles) are written through the I²C interface. The outputs drive "4-wire" fans directly, or can be used to modulate the fan's power terminals using an external pass transistor.

Tachometer inputs monitor fan tachometer logic outputs for precise (±1%) monitoring and control of fan RPM as well as detection of fan failure. Six pins are dedicated tachometer inputs. Any of the six PWM outputs can also be configured to serve as tachometer inputs.

The PWM_START inputs select the PWM output status at startup to ensure appropriate fan drive when power is first applied.

To ensure low acoustic impact of fan control, all changes in PWM duty cycle take place at a controlled, programmable rate.

The MAX31790's 3.0V to 5.5V supply voltage range and I²C-compatible interface make it ideal for fan control in a wide range of cooling applications. The MAX31790 is available in a 28-pin TQFN package and operates over the -40°C to +125°C temperature range.

Key Features

Controls Up to Six Independent Fans with PWM Drive
Up to 12 Tachometer Inputs
Controlled Duty Cycle Rate-of-Change for Best Acoustics
I²C Bus Interface with Timeout and Watchdog
3.0V to 5.5V Supply Voltage Range
1.5mA (typ) Operating Supply Current

DS28EL15

DeepCover Secure Authenticator with 1-Wire SHA-256 and 512-Bit User EEPROM

Protect Your Development Investment with Crypto-Strong Authentication and Advanced Physical Security

Description

DeepCover^™ embedded security solutions cloak sensitive data under multiple layers of advanced physical security to provide the industry's most secure key storage possible. The Deepcover Secure Authenticator (DS28EL15) combines crypto-strong bidirectional secure challenge-and-response authentication functionality with an implementation based on the FIPS 180-3-specified Secure Hash Algorithm (SHA-256). A 512-bit userprogrammable EEPROM array provides nonvolatile storage of application data. Additional protected memory holds a read-protected secret for SHA-256 operations and settings for memory protection control. Each device has its own guaranteed unique 64-bit ROM identification number (ROM ID) that is factory programmed into the chip. This unique ROM ID is used as a fundamental input parameter for cryptographic operations and also serves as an electronic serial number within the application. A bidirectional security model enables two-way authentication between a host system and slave-embedded DS28EL15. Slave-to-host authentication is used by a host system to securely validate that an attached or embedded DS28EL15 is authentic. Host-to-slave authentication is used to protect DS28EL15 user memory from being modified by a nonauthentic host. The DS28EL15 communicates over the single-contact 1-Wire^® bus at overdrive speed. The communication follows the 1-Wire protocol with the ROM ID acting as node address in the case of a multidevice 1-Wire network.

Key Features

Symmetric-Key-Based Bidirectional Secure Authentication Model Based on SHA-256
Strong Authentication with a High-Bit-Count User-Programmable Secret and Input Challenge
512 Bits of User EEPROM Partitioned Into Two Pages of 256 Bits
User-Programmable and Irreversible EEPROM Protection Modes Including Authentication, Write and Read Protect, and OTP/EPROM Emulation
Unique Factory-Programmed, 64-Bit Identification Number
Single-Contact 1-Wire Interface
Operating Range: 1.8V ±5%, -40°C to +85°C
±8kV HBM ESD Protection (typ)
6-Pin TDFN-EP Package