
1
FN8239.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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ISL88694
SMBus Accelerator (SMA)
The ISL88694 SMBus accelerator (SMA) is a dual active
pull-up bus terminator designed to improve data
transmission speed on SMBus or similar 2-wire serial bus
interfaces. The ISL88694 is also compatible to the I2C serial
bus.
The SMA detects rising input transitions with two internal
voltage references and two comparators per channel. After
the voltage on a data line crosses the first threshold
(VTRIPL), the boost pull-up current source is activated to
speed transition. After the voltage crosses the second
threshold (VTRIPH), the boost pull-up current source is de-
activated, leaving an active pull-up current of 275A on the
line. When both channels are HIGH, the pull-up current for
both lines is reduced to 100A to save power. Internal logic
ensures that the active and boost pull-up current sources are
not activated during downward transitions.
The level for VTRIPH is controlled by a bandgap voltage
referred to VDD. This feature makes the switching behavior
invariant for all power supply voltages between 2.7V and
5.5V.
A noise filter on each channel prevents the circuit from
responding to input transitions that do not exceed a voltage-
time threshold. To activate the boost circuit, the input must
The SMA permits operation of the bus at frequencies up to
100kHz, despite the capacitive loads of multiple devices
and/or long PC board traces. Enhanced ESD protection on
the accelerator pins are guaranteed to withstand 8kV ESD
(HBM) events.
The SMBus Accelerator provides an essential function in
SMBus applications because of distributed capacitance of
SMBus and multiple device input capacitances at various
nodes. By incorporating SMA, systems using SMBus or I2C
can reliably increase their bus load without the risk of data
loss.
Features
Active Termination for SMBus lines
Enhances System Bus Signal Rise Time
Increases Bus Capacity While Guaranteeing Data Integrity
2.2mA Rise Time Supply Current
8kV ESD Protection on SDA and SCL Pins
Wide Operating Voltage Range: 2.7V to 5.5V
2-Wire SMBus and I2C Compatible (100kHz)
Small Package - SOT23-5
Pin-for-Pin Compatible with the LTC1694
Pb-Free Available (RoHS Compliant)
Target Applications
Servers
Data Acquisition
Routers
Battery Chargers
Portable Instrumentation
Notebook
PC
Facilities Tracking System
Pinout
ISL88694
(5 LD SOT-23)
TOP VIEW
Ordering Information
PART NUMBER
PACKAGE
TEMP RANGE (°C)
ISL88694IH5
5-pin SOT
-40 to 85
ISL88694IH5Z (Note) 5-pin SOT (Pb-Free)
-40 to 85
Add “-TK” suffix for tape and reel.
NOTE: Intersil Pb-free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which are RoHS compliant and compatible
with both SnPb and Pb-free soldering operations. Intersil Pb-free
products are MSL classified at Pb-free peak reflow temperatures that
meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
VDD
1
2
3
4
5
N.C.
SMBus1
GND
SMBus2
Data Sheet
January 21, 2005