LTC1840: Dual Fan Controller with 2-Wire Interface Data Sheet8/31/2007181K
Features and Benefits
- 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
The LTC1840 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.
- Desktop Computers
- Power Supplies
- Cooling Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
R421 Reliability Data3/23/201866 K
DAC Selector Card9/21/2015587K
I2C Dual Fan Speed Controller Increases Efficiency and Reduces Noise12/1/2001 LT Journal
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|LTC1840CGN#PBF||Material Declaration||Reliability Data||16-Lead SSOP (Narrow 0.15 Inch)|
|LTC1840CGN#TRPBF||Material Declaration||Reliability Data||16-Lead SSOP (Narrow 0.15 Inch)|
|LTC1840IGN#PBF||Material Declaration||Reliability Data||16-Lead SSOP (Narrow 0.15 Inch)|
|LTC1840IGN#TRPBF||Material Declaration||Reliability Data||16-Lead SSOP (Narrow 0.15 Inch)|
|Wafer Fabrication Data||R421 Reliability Data|
Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.
Support & Discussions
Sample & Buy
See our Ordering FAQs for answers to questions about online orders, payment options and more.
Buy Now Pricing
(**) Displayed Buy Now Price and Price Range is based on small quantity orders.
(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Please see the latest communication from our CCO regarding lead times.
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.