JBL MS-8, Руководство по обслуживанию

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1
LTC1694
SMBus/I
2
C Accelerator*
■
Improves SMBus Rise Time Transition
■
Ensures Data Integrity with Multiple Devices
on the SMBus
■
Improves Low State Noise Margin
■
Auto Detect Low Power Standby Mode
■
Wide Supply Voltage Range: 2.7V to 6V
■
Low Profile (1mm) SOT-23 (ThinSOT
TM
) Package
The LT C
®
1694 is a dual SMBus active pull-up designed to
enhance data transmission speed and reliability under all
specified SMBus loading conditions. The LTC1694 is also
compatible with the Philips I
2
C
TM
Bus.
The LTC1694 allows multiple device connections or a
longer, more capacitive interconnect, without compro-
mising slew rates or bus performance, by using two
bilevel hysteretic current source pull-ups.
During positive bus transitions, the LTC1694 current
sources provide 2.2mA to quickly slew the SMBus line.
During negative transitions or steady DC levels, the cur-
rent sources decrease to 275
µ
A to improve negative slew
rate and improve low state noise margins. An auto detect
standby mode reduces supply current if both SCL and
SDA are high.
The LTC1694 is available in a 5-pin SOT-23 package,
requiring virtually the same space as two surface mount
resistors.
■
Notebook and Palmtop Computers
■
Portable Instruments
■
Battery Chargers
■
Industrial Control Application
■
TV/Video Products
■
ACPI SMBus Interface
LTC1694
V
CC
GND
V
CC
5V
C1
0.1
µ
F
SMBus1
SMBus2
SCL
SDA
DEVICE 1
CLK
IN
CLK
OUT
SMBus
DATA
IN
DATA
OUT
DEVICE N
1694 TA01
CLK
IN
CLK
OUT
DATA
IN
DATA
OUT
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
I
2
C is a trademark of Philips Electronics N.V.
*U.S. Patent No. 6,650,174
V
CC
= 5V 1
µ
s/DIV
C
LD
= 200pF
f
SMBus
= 100kHz
1694 TA02
Comparison of SMBus Waveforms for
the LTC1694 vs Resistor Pull-Up
LTC1694
R
PULL-UP
= 15.8k
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
1V/DIV
MS-8
77