PCA9518AD-T [NXP]
IC,BUS CONTROLLER,CMOS,SOP,20PIN;
| 型号： | PCA9518AD-T |
| 厂家： | 
NXP |
| 描述： | IC,BUS CONTROLLER,CMOS,SOP,20PIN 光电二极管 接口集成电路 |
| 文件： | 总2页 (文件大小：209K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
NXP expandable 5-channel
I2C-bus hub PCA9518A
Accommodate more I2C-bus devices
on a single bus
For systems that need capacitance loads greater than the 400 pF specified by the I2C-bus
protocol, this easy-to-use, expandable hub divides the I2C-bus or SMBus into four, eight, or even
twelve 400-pF spokes, so designs can accommodate more ICs on a single bus.
Key features
Applications
4 Accommodates more I2C-bus devices or a longer bus length
4 Mixed 100/400-kHz operation
(up to 400 pF per segment)
4 Expanding PCI slots
4 Bi-directional I2C-bus drivers isolate the I2C-bus capacitance
of each segment without the need for a direction pin
4 Powered-off high impedance I2C-bus pins support hot
insertion
4 Bus isolation for hot-plugging PCI slots
4 Using the main bus to drive multiple system boards
4 Voltage translation to combine 2.5, 3.3- and 5.0-V devices
4 Open drain outputs and fail-safe operation on loss of power
4 Compatible with I2C-bus and SMBus
The PCA9518A separates the I2C-bus into multiple groups of
five 400-pF segments. As a result, capacitance of the I2C-bus
or SMBus is limited only by the number of PCA9518A hubs that
can communicate with each other over the four-wire, inter-hub
expansion bus.
4 Supports 100- and 400-kHz devices and multiple masters
4 Lock-up free operation
4 Multi-master capable repeaters for bus arbitration and clock
stretching, with only one repeater delay between segments
4 Individual segment active HIGH Enable input signals let
segments be individually isolated
Each repeater segment has an enable/disable feature that
electrically isolates the segment from the I2C-bus. This makes
it easy to isolate a 100-kHz segment from the rest of a 400-kHz
system, to allow mixed 100/400-kHz operation. The feature can
also be used to support the PCI management bus with eight PCI
slots, isolate the SMBus when hot-plugging PCI slots, or allow
the main SMBus to drive multiple system boards.
4 ESD protection exceeds 2000 V HBM per JESD22-A114,
200 V MM per JESD22-A115, and 1000 V CDM per JESD22-
C101
4 Latch-up testing conforms to JEDEC Standard JESD78
(exceeds 100 mA)
4 20-pin SO wide (D) and TSSOP (PW) packages
EXPSCL1
EXPSCL1
The PCA9518A can also be used to translate voltages between
2.5-V or 5.0-V I2C-bus and 3.3-V I2C-bus or SMBus segments,
thus extending the life of older 5.0-V circuit blocks while using
newer 3.3-V or 2.5-V devices for improved system performance.
SCL0
Buffer
Buffer
Buffer
SCL4
SCL3
Buffer
Buffer
HUB
LOGIC
SCL1
SCL2
The PCA9518A is designed to work with clock frequencies up to
400 kHz and is suitable for use in multi-master I2C-bus or SMBus
environments.
EXPSDA1
EXPSDA2
SDA0
SDA1
SDA2
Buffer
Buffer
Buffer
SDA4
SDA3
Buffer
Buffer
HUB
LOGIC
The system’s microprocessor or microcontroller can use the
400-kHz I2C-bus or SMBus to poll devices on different system
cards for status or version-control information.
EN1
EN2
EN4
EN3
The PCA9518A segment-hardware disable can isolate a specific
system card socket before the card is removed or inserted.
The segment should be isolated and restored only after a stop
command or when the bus is idle.
PCA9518A Block diagram
The PCA9518A is a wider voltage range (2.3 V to 3.6 V)
version of the PCA9518 and also improves partial power-down
performance, keeping I2C-bus I/O pins in high-impedance
state when VDD is below 2.0 V. The PCA9518 is no longer
recommended for new designs but will be supported until
existing users ramp down.
In systems that have a limited number of device addresses, the
PCA9518A can also be used as a multiplexer, isolating different
segments to support more I2C-bus devices on the bus at once.
In this situation, since the SCL0/SDA0 port can’t be isolated, use
a pull-up resistor to hold the lines high when the port is not in
use.
Ordering information
The operating voltage range is 2.3 to 3.6 V and the operating
temperature range is -40 to +85 °C. The I2C-bus pins are
tolerant to 5.5 V.
Package
SO
Container
Tube
PCA9518A
PCA9518AD
PCA9518AD-T
PCA9518APW
PCA9518APW-T
Tape & Reel
Tube
The Application Note AN255 covers the use of this device and
explains pull-up resistor sizing in detail.
TSSOP
Tape & Reel
V
20
1
2
EXPSCL1
EXPSCL2
SCL0
CC
19 EXPSDA2
18 EXPSDA1
17 EN4
Inter-hub
Expansion Bus
3
Enables
4
SDA0
SCL1
9518A
9518A
9518A
9518A
9518A
5
16 SDA4
Pull-up resistors
required
6
15 SCL4
SDA1
EN1
20
Master
7
14
EN3
I
2C/SMBus
1
2
3
4
5
6
7
8
9 10 1112
13 1415 16
17 181920
8
13 SDA3
12 SCL3
11 EN2
SCL2
Pull-up resistors for
the system cards and
master bus are not shown
9
SDA2
GND
10
Typical expansion application (showing 20 slots that can be disabled)
Pin configuration
www.nxp.com
© 2007 NXP B.V.
Date of release: August 2007
All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The
information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and
may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof
does not convey nor imply any license under patent or other industrial or intellectual property rights.
Document order number: 9397 750 16083
Printed in the USA
相关型号：
PCA9518D-T
Expandable 5-channel I2C hub - I2C-bus: 400 kHz; Inputs: 1 ; Operating temperature: -40~85 Cel; Operating voltage: 3.0~3.6 VDC; Outputs: 4
NXP
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