PCA9541
2-to-1 I2C-bus master selector with interrupt logic and reset
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Product description
The PCA9541 is a 2-to-1 I2C-bus master selector designed for high reliability dual master I2C-bus applications where system operation is required, even when one master fails or the controller card is removed for maintenance. The two masters (for example, primary and back-up) are located on separate I2C-buses that connect to the same downstream I2C-bus slave devices. I2C-bus commands are sent by either I2C-bus master and are used to select one master at a time. Either master at any time can gain control of the slave devices if the other master is disabled or removed from the system. The failed master is isolated from the system and will not affect communication between the on-line master and the slave devices on the downstream I2C-bus.
Two versions are offered for different architectures. PCA9541/01 with channel 0 selected at start-up and PCA9541/03 with no channel selected after start-up.
The interrupt outputs are used to provide an indication of which master has control of the bus. One interrupt input (INT_IN) collects downstream information and propagates it to the 2 upstream I2C-buses (INT0 and INT1) if enabled. INT0 and INT1 are also used to let the previous bus master know that it is not in control of the bus anymore and to indicate the completion of the bus recovery/initialization sequence. Those interrupts can be disabled and will not generate an interrupt if the masking option is set.
A bus recovery/initialization if enabled sends nine clock pulses, a not acknowledge, and a STOP condition in order to set the downstream I2C-bus devices to an initialized state before actually switching the channel to the selected master.
An interrupt is sent to the upstream channel when the recovery/initialization procedure is completed.
An internal bus sensor senses the downstream I2C-bus traffic and generates an interrupt if a channel switch occurs during a non-idle bus condition. This function is enabled when the PCA9541 recovery/initialization is not used. The interrupt signal informs the master that an external I2C-bus recovery/initialization needs to be performed. It can be disabled and an interrupt will not be generated.
The pass gates of the switches are constructed such that the VDD pin can be used to limit the maximum high voltage, which will be passed by the PCA9541. This allows the use of different bus voltages on each pair, so that 1.8 V, 2.5 V, or 3.3 V devices can communicate with 5 V devices without any additional protection.
The PCA9541 does not isolate the capacitive loading on either side of the device, so the designer must take into account all trace and device capacitances on both sides of the device, and pull-up resistors must be used on all channels.
External pull-up resistors pull the bus to the desired voltage level for each channel. All I/O pins are 6.0 V tolerant.
An active LOW reset input allows the PCA9541 to be initialized. Pulling the RESET pin LOW resets the I2C-bus state machine and configures the device to its default state as does the internal Power-On Reset (POR) function.
Features
- 2-to-1 bidirectional master selector
- I2C-bus interface logic; compatible with SMBus standards
- PCA9541/01 powers up with Channel 0 selected
- PCA9541/03 powers up with no channel selected and either master can take control of the bus
- Active LOW interrupt input
- 2 active LOW interrupt outputs
- Active LOW reset input
- 4 address pins allowing up to 16 devices on the I2C-bus
- Channel selection via I2C-bus
- Bus initialization/recovery function
- Bus traffic sensor
- Low Ron 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
- Software identical for both masters
- Low standby current
- Operating power supply voltage range of 2.3 V to 5.5 V
- 6.0 V tolerant inputs
- 0 Hz to 400 kHz clock frequency
- ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD22-A115, and 1000 V CDM per JESD22-C101
- Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
- Packages offered: SO16, TSSOP16, HVQFN16
Applications
- High reliability systems with dual masters
- Gatekeeper multiplexer on long single bus
- Bus initialization/recovery for slave devices without hardware reset
- Allows masters without arbitration logic to share resources
All information on this product information page is subject to the subsequent disclaimers:
Products / Packages
| Type number | Orderable part number | Ordering code (12NC) | Product status | Package | Packing | Marking | ECCN |
|---|---|---|---|---|---|---|---|
| PCA9541BS/03 | PCA9541BS/03,118 | 9352 733 18118 | Volume production | SOT629-1 (HVQFN16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541BS/01 | PCA9541BS/01,118 | 9352 732 99118 | Volume production | SOT629-1 (HVQFN16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541D/03 | PCA9541D/03,112 | 9352 733 17112 | Volume production | SOT109-1 (SO16) | Tube | Standard Marking | |
| PCA9541D/03 | PCA9541D/03,118 | 9352 733 17118 | Volume production | SOT109-1 (SO16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541D/01 | PCA9541D/01,112 | 9352 732 98112 | Volume production | SOT109-1 (SO16) | Tube | Standard Marking | |
| PCA9541D/01 | PCA9541D/01,118 | 9352 732 98118 | Volume production | SOT109-1 (SO16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541PW/03 | PCA9541PW/03,118 | 9352 733 16118 | Volume production | SOT403-1 (TSSOP16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541PW/03 | PCA9541PW/03,112 | 9352 733 16112 | Volume production | SOT403-1 (TSSOP16) | Tube | Standard Marking | |
| PCA9541PW/01 | PCA9541PW/01,112 | 9352 732 97112 | Volume production | SOT403-1 (TSSOP16) | Tube | Standard Marking | |
| PCA9541PW/01 | PCA9541PW/01,118 | 9352 732 97118 | Volume production | SOT403-1 (TSSOP16) | Reel Pack, SMD, 13" | Standard Marking |
The variants in the table below are discontinued. See the table Discontinuation information at the bottom of this page for more information.
| Type number | Orderable part number | Ordering code (12NC) | Product status | Package | Packing | Marking | ECCN |
|---|---|---|---|---|---|---|---|
| PCA9541BS/02 | PCA9541BS/02,118 | 9352 733 15118 | Withdrawn Replacement product | SOT629-1 (HVQFN16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541D/02 | PCA9541D/02,112 | 9352 733 14112 | Withdrawn Replacement product | SOT109-1 (SO16) | Tube | Standard Marking | |
| PCA9541D/02 | PCA9541D/02,118 | 9352 733 14118 | Withdrawn Replacement product | SOT109-1 (SO16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541PW/03/G | PCA9541PW/03/G,118 | 9352 822 87118 | Withdrawn Replacement product | SOT403-1 (TSSOP16) | Reel Pack, SMD, 13" | Standard Marking | |
| PCA9541PW/02 | PCA9541PW/02,112 | 9352 733 13112 | Withdrawn Replacement product | SOT403-1 (TSSOP16) | Tube | Standard Marking | |
| PCA9541PW/02 | PCA9541PW/02,118 | 9352 733 13118 | Withdrawn Replacement product | SOT403-1 (TSSOP16) | Reel Pack, SMD, 13" | Standard Marking |
Discontinuation information
| Type number | Ordering code (12NC) | Last-time buy date | Last-time delivery date | Replacement product | DN Notice | Status | Comments |
|---|---|---|---|---|---|---|---|
| PCA9541BS/02 | 935273315118 | 1-Oct-07 | 31-Mar-08 | PCA9541BS/01, PCA9541BS/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541D/02 | 935273314112 | 1-Oct-07 | 31-Mar-08 | PCA9541D/01 or PCA9541D/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541D/02 | 935273314118 | 1-Oct-07 | 31-Mar-08 | PCA9541D/01 or /03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541PW/03/G | 935282287118 | 31-Mar-11 | 30-Jun-11 | PCA9541PW/03 | DN 66 |
| Standard End of Life. Discontinued /G version only. |
| PCA9541PW/02 | 935273313112 | 1-Oct-07 | 31-Mar-08 | PCA9541PW/01, PCA9541PW/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541PW/02 | 935273313118 | 1-Oct-07 | 31-Mar-08 | PCA9541PW/01, PCA9541PW/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
Parametrics of this product
| Type number | Package | Inputs | Outputs | INTERRUPT | Operating voltage(VDC) | I²C-bus(kHz) | Operating temp.(Cel) | # of Addresses | Note | POWER-ON RESET |
|---|---|---|---|---|---|---|---|---|---|---|
| PCA9541BS/03 | SOT629-1 (HVQFN16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | No channel selected on pwr up/reset | yes |
| PCA9541BS/01 | SOT629-1 (HVQFN16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | Channel 0 selected on pwr up/reset | yes |
| PCA9541D/03 | SOT109-1 (SO16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | No channel selected on pwr up/reset | yes |
| PCA9541D/01 | SOT109-1 (SO16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | Channel 0 selected on pwr up/reset | yes |
| PCA9541PW/03 | SOT403-1 (TSSOP16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | No channel selected on pwr up/reset | yes |
| PCA9541PW/01 | SOT403-1 (TSSOP16) | 2 (masters) | 1 (shared slave) | yes | 2.3~5.5 | 400 | -40~85 | 16 | Channel 0 selected on pwr up/reset | yes |
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Quality, reliability & chemical content
| Type number | Orderable part number | Chemical content | RoHS | Leadfree conversion date | RHF | IFR (FIT) | MTBF (hours) | MSL | MSL LF |
|---|---|---|---|---|---|---|---|---|---|
| PCA9541BS/03 | PCA9541BS/03,118 | PCA9541BS/03 |  | Always Pb-free |  | 1 | 1 | ||
| PCA9541BS/01 | PCA9541BS/01,118 | PCA9541BS/01 | | Always Pb-free | | 1 | 1 | ||
| PCA9541D/03 | PCA9541D/03,112 | PCA9541D/03 | | week 6, 2004 |  | 1 | 1 | ||
| PCA9541D/03 | PCA9541D/03,118 | PCA9541D/03 | | week 6, 2004 | | 1 | 1 | ||
| PCA9541D/01 | PCA9541D/01,112 | PCA9541D/01 | | week 6, 2004 | | 1 | 1 | ||
| PCA9541D/01 | PCA9541D/01,118 | PCA9541D/01 | | week 6, 2004 | | 1 | 1 | ||
| PCA9541PW/03 | PCA9541PW/03,118 | PCA9541PW/03 | | week 48, 2004 | | 1 | 1 | ||
| PCA9541PW/03 | PCA9541PW/03,112 | PCA9541PW/03 | | week 48, 2004 | | 1 | 1 | ||
| PCA9541PW/01 | PCA9541PW/01,112 | PCA9541PW/01 | | week 48, 2004 | | 1 | 1 | ||
| PCA9541PW/01 | PCA9541PW/01,118 | PCA9541PW/01 | | week 48, 2004 | | 1 | 1 |
The variants in the table below are discontinued. See the table Discontinuation information at the bottom of this page for more information.
Quality and reliability disclaimerDiscontinuation information
| Type number | Ordering code (12NC) | Last-time buy date | Last-time delivery date | Replacement product | DN Notice | Status | Comments |
|---|---|---|---|---|---|---|---|
| PCA9541BS/02 | 935273315118 | 1-Oct-07 | 31-Mar-08 | PCA9541BS/01, PCA9541BS/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541D/02 | 935273314112 | 1-Oct-07 | 31-Mar-08 | PCA9541D/01 or PCA9541D/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541D/02 | 935273314118 | 1-Oct-07 | 31-Mar-08 | PCA9541D/01 or /03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541PW/03/G | 935282287118 | 31-Mar-11 | 30-Jun-11 | PCA9541PW/03 | DN 66 |
| Standard End of Life. Discontinued /G version only. |
| PCA9541PW/02 | 935273313112 | 1-Oct-07 | 31-Mar-08 | PCA9541PW/01, PCA9541PW/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
| PCA9541PW/02 | 935273313118 | 1-Oct-07 | 31-Mar-08 | PCA9541PW/01, PCA9541PW/03 | DN 59 |
| Limited Supply. This is a Boeblingen plant closure discontinued part type. |
Documentation for this product
| Type | Format | Title | Date |
|---|---|---|---|
| Data sheet | 2-to-1 I2C-bus master selector with interrupt logic and reset (v.7.0) | 2009-07-02 | |
| Application note | I2C manual (v.1.0) | 2003-03-27 | |
| Application note | PCA954X FAMILY OF I²C / SMBus MULTIPLEXERS and SWITCHES (v.2.0) | 2004-10-01 | |
| Application note | A guide to designing for ESD and EMC (v.2.0) | 2010-01-22 | |
| Brochure | Add design fl exibility with multi-channel I2C/SMBus muxes and switches; NXP 2-, 4-, and 8-channel I2C/SMBus muxes and switches PCA954x (v.1.0) | 2008-07-01 | |
| Leaflet | Easily isolate each master in dual master I2C-bus applications; NXP 2-to-1 I2C-bus master selector PCA9541 with interrupt logic and reset (v.1.0) | 2010-11-04 | |
| Leaflet | I2C Selection Guide 2H 2011 (v.1.0) | 2011-09-29 | |
| Other type | DesignCon 2003 TecForum I 2 C Bus Overview (v.1.0) | 2003-01-27 | |
| User manual | I2C-bus specification and user manual (v.3.0) | 2007-06-26 | |
| User manual | I2C Demonstration Board 2005-1 Quick Start Guide (v.1.0) | 2006-06-13 |
Support links
- IBIS and HSPICE Model (standardics.nxp.com/support/tools/)
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