PCA9545A Datasheet, PDF (1/28 Pages) Texas Instruments – 4-CHANNEL I2C AND SMBus SWITCH WITH INTERRUPT LOGIC AND RESET FUNCTIONS

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PCA9545A
4-CHANNEL I²C AND SMBus SWITCH
WITH INTERRUPT LOGIC AND RESET FUNCTIONS
SCPS147C – OCTOBER 2005 – REVISED OCTOBER 2006
FEATURES
• 1-of-4 Bidirectional Translating Switches
• I²C Bus and SMBus Compatible
• Four Active-Low Interrupt Inputs
• Active-Low Interrupt Output
• Active-Low Reset Input
• Two Address Pins, Allowing up to Four
Devices on the I²C Bus
• Channel Selection Via I²C Bus, In Any
Combination
• Power Up With All Switch Channels
Deselected
• Low R_ON Switches
• Allows Voltage-Level Translation Between
1.8-V, 2.5-V, 3.3-V, and 5-V Buses
• No Glitch on Power Up
• Supports Hot Insertion
• Low Standby Current
• Operating Power-Supply Voltage Range of
2.3 V to 5.5 V
• 5.5-V Tolerant Inputs
• 0 to 400-kHz Clock Frequency
• Latch-Up Performance Exceeds 100 mA Per
JESD 78
• ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
DGV, DW, OR PW PACKAGE
(TOP VIEW)
RGW PACKAGE
(TOP VIEW)
RGY PACKAGE
(TOP VIEW)
A0 ¹
A1 ²
RESET ³
INT0 ⁴
SD0 ⁵
SC0 ⁶
INT1 ⁷
SD1 ⁸
SC1 ⁹
GND ¹⁰
20 _VCC
19 _SDA
18 _SCL
17 _INT
16 _SC3
15 _SD3
14 _INT3
13 _SC2
12 _SD2
11 _INT2
RESET
INT0
SD0
SC0
INT1
20 19 18 17 16
1
15
2
14
3
13
4
12
5
11
6 7 8 9 10
INT
SC3
SD3
INT3
SC2
A1 2 ¹
RESET 3
INT0 4
SD0 5
SC0 6
INT1 ⁷
SD1 8
SC1 9 ₁₀
20 ₁₉
18
17
16
15
14
13
12
11
SDA
SCL
INT
SC3
SD3
INT3
SC2
SD2
DESCRIPTION/ORDERING INFORMATION
The PCA9545A is a quad bidirectional translating switch controlled via the I²C bus. The SCL/SDA upstream pair
fans out to four downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can
be selected, determined by the contents of the programmable control register. Four interrupt inputs (INT3–INT0),
one for each of the downstream pairs, are provided. One interrupt (INT) output acts as an AND of the four
interrupt inputs.
An active-low reset (RESET) input allows the PCA9545A to recover from a situation in which one of the
downstream I²C buses is stuck in a low state. Pulling RESET low resets the I²C state machine and causes all
the channels to be deselected, as does the internal power-on reset function.
The pass gates of the switches are constructed such that the V_CC pin can be used to limit the maximum high
voltage, which will be passed by the PCA9545A. This allows the use of different bus voltages on each pair, so
that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts, without any additional protection. External
pullup resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5.5-V tolerant.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005–2006, Texas Instruments Incorporated