ISL88694_14 [INTERSIL]

SMBus Accelerator (SMA);


型号：	ISL88694_14
厂家：	Intersil
描述：	SMBus Accelerator (SMA)
文件：	总7页 (文件大小：250K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ISL88694

Data Sheet

January 21, 2005

FN8239.1

SMBus Accelerator (SMA)

Features

• Active Termination for SMBus lines

The ISL88694 SMBus accelerator (SMA) is a dual active

pull-up bus terminator designed to improve data

• Enhances System Bus Signal Rise Time

• Increases Bus Capacity While Guaranteeing Data Integrity

• 2.2mA Rise Time Supply Current

transmission speed on SMBus or similar 2-wire serial bus

interfaces. The ISL88694 is also compatible to the I 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

• 8kV ESD Protection on SDA and SCL Pins

• Wide Operating Voltage Range: 2.7V to 5.5V

), the boost pull-up current source is activated to

• 2-Wire SMBus and I C Compatible (100kHz)

TRIPL

speed transition. After the voltage crosses the second

threshold (V ), the boost pull-up current source is de-

• Small Package - SOT23-5

TRIPH

• Pin-for-Pin Compatible with the LTC1694

• Pb-Free Available (RoHS Compliant)

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.

Target Applications

• Servers

The level for V

is controlled by a bandgap voltage

TRIPH

• Data Acquisition

• Routers

referred to V . This feature makes the switching behavior

invariant for all power supply voltages between 2.7V and

5.5V.

• Battery Chargers

• Portable Instrumentation

• Notebook

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

• PC

exceed V

by 100Vns (typical) (See Figure 10).

TRIPL

• Facilities Tracking System

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.

Pinout

ISL88694

(5 LD SOT-23)

TOP VIEW

The SMBus Accelerator provides an essential function in

SMBus applications because of distributed capacitance of

SMBus and multiple device input capacitances at various

SMBus1

SMBus2

GND

N.C.

nodes. By incorporating SMA, systems using SMBus or I C

can reliably increase their bus load without the risk of data

loss.

Ordering Information

PART NUMBER

PACKAGE

TEMP RANGE (°C)

-40 to 85

ISL88694IH5

5-pin SOT

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.

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

ISL88694

Pin Descriptions

SOT-23

SYMBOL

DESCRIPTION

Supply Voltage

Ground

GND

N.C.

No Connect

SMBus1

SMBus2

Active Pull-Up for SMBus

System Diagram

ISL88694

SMBus1

SMBus2

GND

BUS SIGNALS

DATA

CLK

DATA IN

CLK IN

Devices;

SBS, PCI,

Compact PCI,

CLK OUT

DATA OUT

PMCI, ACPI,

ICMB, IPMI,

IPMB,SMBus,

I C, 2-Wire.

Device 1

Device N

IC Block Diagram

1.825mA 175µA 100µA

TRIPH

-0.5V

SMBus1

SMBus2

Control

TRIPL

0.75V

TRIPH

-0.5V

Control

TRIPL

0.75V

1.825mA 175µA 100µA

GND

FN8239.1

January 21, 2005

ISL88694

Absolute Maximum Ratings

Recommended Operating Conditions

Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C

Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.5V

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 +0.3V

Lead temperature (soldering, 10 seconds) . . . . . . . . . . . . . . .300°C

ESD min other pins (HBM). . . . . . . . . . . . . . . . . . . . . . . . . . . . .>2kV

ESD SMBus1 and SMBus2 pins (HBM) . . . . . . . . . . . . . . . . . .>8kV

CAUTION: Absolute Maximum Ratings indicate limits beyond which permanent damage to the device and impaired reliability may 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 guaranteed specifications and test conditions, see Electrical Specifications. The guaranteed 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 Over operating conditions unless otherwise specified, Typical values are measured at V

= 3.3V and

= +25°C

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNIT

ANALOG PARAMETERS

Supply Voltage Range

Ramp Rate

2.7

5.5

V/msec

µA

0.05

DD RAMP

Supply Current

SMBus1=SMBus2=Open

100

125

350

Standby Pull-Up Current

Active Pull-Up Current

SMBus1=SMBus2=V -1.0V

µA

OUT_SB

OUT_A1

OUT_A2

OUT_B1

OUT_B2

SMBus1=GND; SMBus2=Open

SMBus1= Open; SMBus2=GND

125

1.6

275

2.2

0.75

µA

Boost Pull-Up Current (Figure 1)

<SMBus1<V

<SMBus2<V

, SMBus2=Open

, SMBus1=Open

TRIPL

TRIPH

1.6

TRIPH

Input Voltage Threshold Low

Input Voltage Threshold High

SMBus Max Frequency

0.65

0.85

TRIPL

TRIPH

MAX

-0.60

- 0.50

- 0.40

100

kHz

V-nsec

NSS

Noise Spike Suppression

(Note 1) (Figure 10)

NOTES:

1. Measured as area under triangular waveform above V

, with time as base and V as height (See Figure 10).

TRIPL IN

FN8239.1

January 21, 2005

ISL88694

Typical Performance Curves

370

3.75

2.60

2.45

2.30

2.15

2.00

1.85

1.70

1.55

350

330

310

VDD=5.5V

VDD=2.7V

290

270

250

230

210

VDD=5.5V

VDD=2.7V

-60 -40 -20

80 100

-60 -40 -20

80 100

TEMPERATURE (°C)

FIGURE 2. BOOST PULL-UP CURRENT. SMBus PIN = V /2.

FIGURE 1. ACTIVE PULL-UP CURRENT. SMBus PIN=0V

120

110

100

0.95

0.90

0.85

0.80

VDD=5.5V

VDD=2.7V

0.75

0.70

0.65

0.60

0.55

VDD=2.7V

-60 -40 -20

80 100

-60 -40 -20

80 100

TEMPERATURE (°C)

FIGURE 3. STANDBY PULL-UP CURRENT. SMBus1,2=V -0.5V

FIGURE 4. V

VOLTAGE

TRIPL

FN8239.1

January 21, 2005

ISL88694

Typical Performance Curves (Continued)

0.70

0.65

0.60

0.55

VDD=5.5V

VDD=2.7V

VDD=5.5V

VDD=2.7V

0.50

0.45

0.40

0.35

0.30

-60 -40 -20

80 100

-60 -40 -20

80 100

TEMPERATURE (°C)

FIGURE 6. I

CURRENT. SMBus1=SMBus2=OPEN.

FIGURE 5. V

VOLTAGE

TRIPH

3.5

3.0

2.5

2.0

1.5

1.0

0.5

VDD=5.0V

VDD=2.7V

SMBus VOLTAGE (V)

FIGURE 7. BOOST PULL-UP CURRENT vs. SMBus VOLTAGE

connected to the bus must have an open-drain or open-

collector to perform the wired-AND function.

Functional Description

SMBus Overview

Simple pull-up resistors on the clock and data lines work well

unless there are long signal lines or many devices

connected to the bus. Then, the combined capacitance of

the bus increases the rise time on the signal to such an

extent that the communication becomes unreliable or fails to

meet the bus timing specifications. Smaller resistors can

sometimes compensate for the extra capacitance, but this

increases the current consumption when the signal lines are

pulled LOW.

The SMBus or I C bus is a 2-wire multimaster bus, meaning

that more than one device connected to the bus is capable of

controlling it. Master devices communicate to other master

or slave devices using one clock and one data line. These

are both bidirectional.

In order to allow multimaster operation without bus

contention, it is necessary to allow each bus to be connected

to a positive supply voltage via a current-source or pull-up

resistor (see “System Diagram” on page 2). When the bus is

free, both lines are HIGH. The output stages of devices

FN8239.1

January 21, 2005

ISL88694

ISL88694 Operation

With ISL88694 SMA

To improve the operation of the SMBus where larger bus

capacitance exists, the ISL88694 provides active pull-up

using switched current sources. When the bus is idle and

both lines are HIGH, a standby pull-up current of 100µA is

used to maintain the signal level while minimizing power

TRIPH

consumption. When either of the two signals is pulled LOW,

an active pull-up current of 275µA maintains a good V

noise margin.

With RC

Pullup

TRIPL

When the bus line is released, it is pulled high by the

ISL88694 active current until the voltage exceeds the

level for a period of time. This voltage-time

TRIPL

R=15.8K

combination filters out noise on the signal line. Once the

ISL88694 detects a valid rising edge, a 2.2mA boost current

pulls the bus line high very quickly (see Figure 8). This boost

C= 200pF

current turns off when the input level reaches the V

TRIPH

FIGURE 9. ISL88694 SMBus SYSTEM BOOST PULL-UP

threshold and the pull-up current returns to the active level. If

both inputs are HIGH, the pull-up current drops to the

standby level of 100µA.

COMPARED TO RESISTOR PULL-UP (V

2.7V).

With ISL88694 SMA

TRIPH

With SMA

TRIPH

Without SMA

With RC

Pullup

TRIPL

R=15.8K

>20Vns

C= 200pF

(Typical)

Gnd

SMBus1

SMBus2

FIGURE 10. NOISE SUPPRESSION. BOOST CURRENT

FIGURE 8. ISL88694 SMBus SYSTEM BOOST PULL-UP

APPLIED WHEN INPUT SIGNAL EXCEEDS 20Vns

(TYPICAL).

COMPARED TO RESISTOR PULL-UP (V

5.5V).

FN8239.1

January 21, 2005

ISL88694

Package Outline Drawing

5-Lead, SOT23, Package Code H5

0.007 (0.20)

0.0006 (0.15)

0.108 (2.75) BSC

0.054 (1.38) BSC

0.065 (1.65)

0.061 (1.55)

0.35 H A-B

0.35 C A-B

2X N/2 TIPS

0.075 (1.90) BSC

12° REF.

TYP.

0.118 (3.00)

0.110 (2.80)

0.033 (0.85)

0.035 (0.90)

0.038 (0.95)

BSC

Parting Line

0.10 R MIN.

0.20 in

0.10 R

MIN.

Seating Plane

0.0008 (0.02)

0.0040 (0.10)

SEATING PLANE

0.043 (1.10) MAX

.019 (0.50)

.012 (0.30)

0-8°C

0.575 REF.

NOTES:

1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)

2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH

3. DIMENSIONING AND TOLERANCES PER ASME, Y14.5-1994

4. THIS PART IS COMPLIANT WITH JEDEC SPECIFICATION MO-193.

5. THIS PART IS FULL COMPLIANCE TO EIAJ SPECIFICATION SC-74

All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.

Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without

notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and

reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result

from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

FN8239.1

January 21, 2005

ISL88694_14 [INTERSIL]

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