LTC1840 Dual Fan Controller with 2-Wire Interface

The LTC®1840 is a fan controller with two 8-bit current output DACs, two tachometer interfaces, and four general purpose I/O (GPIO) pins. It operates from a single supply with a range of 2.7V to 5.75V. A current output DAC is used to control an external switching regulator, which controls the fan speed. A current output DAC and tachometer allow a controller to form a closed control loop on fan velocity. The GPIO pins can be used as digital inputs or open drain pull-down outputs.

The part features a simple 2-wire I²C and SMBus compatible serial interface that allows communication between many devices. The interface includes a fault status register that reflects the state of the part and which can be polled to find the cause of a fault condition. Other operational characteristics of the part, such as DAC output currents, GPIO modes, and tachometer frequency, are also programmed through the serial interface. Two address pins provide nine possible device addresses.

The BLAST pin is provided to force the DAC output currents to program the maximum regulator output voltages through a single pin and gate the operation of the serial access timer

产品特点 Features

Two 8-Bit Current DACs
DACs Guaranteed Monotonic
Known IC State on Power-Up
Serial Interface Watchdog Timer with Disable
2-Wire Serial Interface Compatible with I2C™ and SMBus
2 Programmable Fan Tachometer Interfaces
4 Programmable General Purpose I/Os
Small 16-Pin SSOP Package
Single 2.7V to 5.75V Supply Operation
Fault Output Signal
Status Register
Fan Blasting Function
Nine Addresses Using Two Programming Lines

应用

Servers
Desktop Computers
Power Supplies
Cooling Systems

典型应用图

LTC1840 订购信息和价格参考Package Variations and Pricing

器件型号	封装	引脚	温度	价格 (以 1 ~ 99 片为批量)	价格 (以 1000 片为批量) *
LTC1840CGN	SSOP	16	C	$3.75	$2.75
LTC1840CGN#PBF	SSOP	16	C	$3.75	$2.75
LTC1840CGN#TR	SSOP	16	C		$2.81
LTC1840CGN#TRPBF	SSOP	16	C		$2.81
LTC1840IGN	SSOP	16	I	$4.25	$3.15
LTC1840IGN#PBF	SSOP	16	I	$4.25	$3.15
LTC1840IGN#TR	SSOP	16	I		$3.21
LTC1840IGN#TRPBF	SSOP	16	I		$3.21

LTC1840 数据手册及相关资料下载

数据手册(英文) : LTC1840 - Dual Fan Controller with 2-Wire Interface.PDF
设计要点 (英文) : DN270 - LTC1840: I2C Fan Control Ensures Continuous System Cooling.PDF
可靠性数据 : R421 Reliability Data .PDF
LT Journal: Dec 2001 I2C Dual Fan Speed Controller Increases Efficiency and Reduces Noise..PDF