DATASHEET
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 with the I
2
C
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
(V
TRIPL
), the boost pull-up current source is activated to
speed transition. After the voltage crosses the second
threshold (V
TRIPH
), the boost pull-up current source is de-
activated, leaving an active pull-up current of 275µA on the
line. When both channels are HIGH, the pull-up current for
both lines is reduced to 100µA to save power. Internal logic
ensures that the active and boost pull-up current sources are
not activated during downward transitions.
The level for V
TRIPH
is controlled by a bandgap voltage
referred to V
DD
. 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
exceed V
TRIPL
by 100Vns (typical) (See Figure 10).
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 I
2
C
can reliably increase their bus load without the risk of data
loss.
FN8239
Rev.2.00
Jan 25, 2019
Features
• Active termination for SMBus lines
• Enhances system bus signal rise time
• Increases bus capacity while ensuring 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 I
2
C 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
Related Literature
For a full list of related documents, visit our website:
•
ISL88694
device page
FN8239 Rev.2.00
Jan 25, 2019
Page 1 of 10
ISL88694
Ordering Information
PART NUMBER
(Notes
2, 3)
ISL88694IH5Z-TK
NOTES:
1. See
TB347
for details about reel specifications.
2. 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. 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.
3. For Moisture Sensitivity Level (MSL), see the
ISL88694
device page. For more information about MSL, see
TB363.
4. The part marking is located on the bottom of the part.
PART MARKING
(Note
4)
AKM
TEMP RANGE
(°C)
-40 to +85
TAPE AND REEL
(Units) (Note
1)
1k
PACKAGE
(RoHS Compliant)
5-pin SOT
PKG.
DWG. #
P5.064
Pinout
5 LD SOT-23
TOP VIEW
V
DD
GND
N.C.
5
1
2
3
SMBus1
4
SMBus2
Pin Descriptions
SOT-23
1
2
3
4
5
SYMBOL
V
DD
GND
N.C.
SMBus2
SMBus1
Supply Voltage
Ground
No Connect
Active Pull-Up for SMBus
Active Pull-Up for SMBus
DESCRIPTION
FN8239 Rev.2.00
Jan 25, 2019
Page 2 of 10
ISL88694
Absolute Maximum Ratings
Supply Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . . . . -1V to 6.5V
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +135°C
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°C
Voltage on pins . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to V
DD
+0.3V
Lead temperature (soldering, 10 seconds) . . . . . . . . . . . . . . . 300°C
ESD min other pins (HBM). . . . . . . . . . . . . . . . . . . . . . . . . . . . .>2kV
ESD SMBus1 and SMBus2 pins (HBM) . . . . . . . . . . . . . . . . . .>8kV
Recommended Operating Conditions
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.5V
CAUTION: Absolute Maximum Ratings indicate limits beyond which permanent damage to the device and impaired reliability can occur. These are stress ratings
provided for information only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification are not implied.
For assured specifications and test conditions, see Electrical Specifications. The assured specifications apply only for the test conditions listed. Some performance
characteristics may degrade when the device is not operated under the listed test conditions.
Electrical Specifications
PARAMETER
ANALOG PARAMETERS
Supply Voltage Range
V
DD
Ramp Rate
Supply Current
Standby Pull-Up Current
Active Pull-Up Current
Over operating conditions unless otherwise specified, Typical values are measured at V
DD
= 3.3V and
T
A
= +25°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
V
DD
V
DD RAMP
I
DD
I
OUT_SB
I
OUT_A1
I
OUT_A2
SMBus1 = SMBus2 = Open
SMBus1 = SMBus2 = V
DD
-1.0V
SMBus1 = GND; SMBus2 = Open
SMBus1 = Open; SMBus2 = GND
V
TRIPL
<SMBus1<V
TRIPH
, SMBus2 = Open
V
TRIPL
<SMBus2<V
TRIPH
, SMBus1 = Open
2.7
0.05
80
80
125
125
1.6
1.6
0.65
275
275
2.2
2.2
0.75
5.5
50
100
125
350
350
V
V/msec
µA
µA
µA
µA
mA
mA
Boost Pull-Up Current (Figure
1)
I
OUT_B1
I
OUT_B2
Input Voltage Threshold Low
Input Voltage Threshold High
SMBus Max Frequency
Noise Spike Suppression
(Note
5)
(Figure
10)
NOTES:
V
TRIPL
V
TRIPH
f
MAX
NSS
0.85
V
V
kHz
V-nsec
V
DD
-0.60 V
DD
- 0.50 V
DD
- 0.40
100
20
5. Measured as area under triangular waveform above V
TRIPL
, with time as base and V
IN
as height (see
Figure 10 on page 7).
FN8239 Rev.2.00
Jan 25, 2019
Page 4 of 10
ISL88694
Typical Performance Curves
370
ACTIVE PULL-UP CURRENT, I
OUT_A
(µA)
BOOST PULL-UP CURRENT, I
OUT_B
(µA)
350
330
310
290
270
250
230
210
-60
VDD = 2.7V
VDD = 5.5V
3.75
2.60
2.45
2.30
2.15
2.00
1.85
1.70
1.55
-60
VDD = 2.7V
VDD = 5.5V
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 1. ACTIVE PULL-UP CURRENT, SMBus PIN = 0V
FIGURE 2. BOOST PULL-UP CURRENT, SMBus PIN = V
DD
/2
120
STANDBY PULL-UP CURRENT, I
OUT_SB
(µA)
INPUT THRESHOLD LOW, V
TRIPL
(V)
110
100
90
VDD = 5.5V
80
70
60
50
40
-60
VDD = 2.7V
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
-60
VDD = 5.5V
VDD = 2.7V
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 3. STANDBY PULL-UP CURRENT,
SMBus1, 2 = V
DD
-0.5V
FIGURE 4. V
TRIPL
VOLTAGE
FN8239 Rev.2.00
Jan 25, 2019
Page 5 of 10
Embedded System
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