Datasheet Linear Technology LTC1840

Manufacturer	Linear Technology
Series	LTC1840

Dual Fan Controller with 2-Wire Interface

Datasheets

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PDF, 186 Kb, File uploaded: Aug 22, 2017

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Packaging

	LTC1840CGN#PBF	LTC1840CGN#TRPBF	LTC1840IGN#PBF	LTC1840IGN#TRPBF
N	1	2	3	4
Package	SSOP-16 Package Outline Drawing	SSOP-16 Package Outline Drawing	SSOP-16 Package Outline Drawing	SSOP-16 Package Outline Drawing
Package Code	GN	GN	GN	GN
Package Index	05-08-1641 (GN16)	05-08-1641 (GN16)	05-08-1641 (GN16)	05-08-1641 (GN16)
Pin Count	16	16	16	16

Parametrics

Parameters / Models	LTC1840CGN#PBF	LTC1840CGN#TRPBF	LTC1840IGN#PBF	LTC1840IGN#TRPBF
Bits, bits	8	8	8	8
DAC INL, LSB	4	4	4	4
DACs	2	2	2	2
DNL, LSB	0.9	0.9	0.9	0.9
Export Control	no	no	no	no
I/O	Serial I2C	Serial I2C	Serial I2C	Serial I2C
Operating Temperature Range, °C	0 to 70	0 to 70	-40 to 85	-40 to 85
Output	Current	Current	Current	Current
Output Range	100uA Sourcing	100uA Sourcing	100uA Sourcing	100uA Sourcing
Power, mW	1.2	1.2	1.2	1.2
Supply Voltage Range	2.7V to 5.5V	2.7V to 5.5V	2.7V to 5.5V	2.7V to 5.5V

Eco Plan

	LTC1840CGN#PBF	LTC1840CGN#TRPBF	LTC1840IGN#PBF	LTC1840IGN#TRPBF
RoHS	Compliant	Compliant	Compliant	Compliant

Design Notes

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LTC1840: I2C Fan Control Ensures Continuous System Cooling &mdash DN270
PDF, 82 Kb, File published: Oct 2, 2001
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I2C Fan Control Ensures Continuous System Cooling
Design Note 270
Dilian Reyes
slowing down due to worn bearings or halted from a
jam will cause an overп¬‚ow in the internal counter and
a corresponding bit is set low in the fault register. The
system controller can then take action, shutting down
the faulty fan and summoning maintenance. Introduction
Linear TechnologyвЂ™s LTC В®1840 is a dual fan speed
controller for high availability servers and other rackbased network and telecom equipment. The LTC1840
offers advanced control and monitoring capabilities,
accessed via an I2C and SMBus compatible 2-wire
serial interface. In addition to two fan speed control
channels, the LTC1840 also includes a fan tachometer and fault monitoring, nine slave addresses
and four general-purpose programmable I/O pins
in a 16-pin SSOP package. Adjusting fan speed to
match instantaneous cooling requirements increases
energy efп¬Ѓciency and reduces noise. By operating at
reduced speeds, fan bearings are subjected to less
wear, increasing fan life and reliability. The chip contains four general purpose input/output
(GPIO) pins that are conп¬Ѓgured independently. As opendrain outputs, they can be set high, low or to pulse at a
1.5Hz rate. The outputs are rated at 10mA sink current
for compatibility with LEDs. Conп¬Ѓgured as inputs, the …

Articles

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I2C Dual Fan Speed Controller Increases Efficiency and Reduces Noise &mdash LT Journal
PDF, 46 Kb, File published: Dec 1, 2001
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DESIGN IDEAS I2C Dual Fan Speed Controller
Increases Efficiency and
by Dilian Reyes
Reduces Noise
Busy servers and rack-based network and telecom equipment rely on
hard-working cooling systems to keep
from melting down. The simplest cooling system is a bank of fans running
at full tilt, all of the time. This approach ensures a cool environment,
but overcompensation is neither efficient, nor is it good for the fans. High
output fans that work full time do not
last very long (their bearings wear
out), are not very efficient (they use
power also), and are noisy (especially
when their bearings wear out). The
LTC1840 dual fan speed controller
reduces the wear on bearings, and
noise, by continuously adjusting fan
speed to match the instantaneous
cooling requirements of the system. REGULATOR
12V VIN FAN POWER (1.36V TO 12VMAX) VO
VFB
1.23V FB R1
105k …

Model Line

Series: LTC1840 (4)

LTC1840CGN#PBF LTC1840CGN#TRPBF LTC1840IGN#PBF LTC1840IGN#TRPBF

Manufacturer's Classification

Data Conversion > Digital-to-Analog Converters (DAC) > Special Function DACs | Unipolar Digital-to-Analog Converters (DAC)
Power Management > Power Control > Fan Speed Controllers