Datasheet LTC1694-1 (Analog Devices)

LTC1694-1 SMBus/I2C Accelerator*
U FEATURES DESCRIPTIO
■
Improves SMBus/I2CTM Rise Time Transition
The LTC®1694-1 is a dual SMBus active pull-up designed ■
Ensures Data Integrity with Multiple Devices
to enhance data transmission speed and reliability under
on the SMBus/I2C
all specified SMBus loading conditions. The LTC1694-1 is ■ Improves Low State Noise Margin also compatible with the Philips I2C Bus. ■ Wide Supply Voltage Range: 2.7V to 6V The LTC1694-1 allows multiple device connections or a ■ Parallel Multiple LTC1694-1 Devices longer, more capacitive interconnect, without compro- for Increased Drive mising slew rates or bus performance, by supplying a high ■ Low Profile (1mm) SOT-23 (ThinSOTTM) Package pull-up current of 2.2mA to slew the SMBus or I2C lines during positive bus transitions
U APPLICATIO S
During negative transitions or steady DC levels, the LTC1694-1 sources zero current. External resistors, one ■ Notebook and Palmtop Computers on each bus line, trigger the LTC1694-1 during positive ■ Portable Instruments bus transitions and set the pull-down current level. These ■ Battery Chargers resistors determine the slew rate during negative bus ■ Industrial Control Application transitions and the logic low DC level. ■ TV/Video Products ■ The LTC1694-1 is available in a 5-pin SOT-23 package. ACPI SMBus Interface , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. I2C is a trademark of Philips Electronics N.V. *U.S. Patent No. 6,650,174
U TYPICAL APPLICATIO Comparison of SMBus Waveforms for
VCC VCC
the LTC1694-1 vs Resistor Pull-Up
5V 5V VCC SMBus1 C1 LTC1694-1 0.1µF GND SMBus2 R R P1 P2 LTC1694-1 1V/DIV SCL RPULL-UP = 15.8k SMBus SDA CLK DATA CLK DATA IN IN IN IN CLK DATA CLK DATA OUT OUT OUT OUT VCC = 5V 1µs/DIV 1694-1 TA02 DEVICE 1 DEVICE N CLD = 200pF fSMBus = 100kHz 1694-1 TA01 16941fa 1