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PCA9515A

ACTIVE

2-bit bidirectional 2.3- to 3.6-V 400-kHz I2C/SMBus buffer

Product details

Features Buffer Protocols I2C Frequency (max) (MHz) 0.4 VCCA (min) (V) 2.3 VCCA (max) (V) 3.6 VCCB (min) (V) 2.3 VCCB (max) (V) 3.6 Supply restrictions VCC Single Supply Rating Catalog Operating temperature range (°C) -40 to 85
Features Buffer Protocols I2C Frequency (max) (MHz) 0.4 VCCA (min) (V) 2.3 VCCA (max) (V) 3.6 VCCB (min) (V) 2.3 VCCB (max) (V) 3.6 Supply restrictions VCC Single Supply Rating Catalog Operating temperature range (°C) -40 to 85
SOIC (D) 8 29.4 mm² 4.9 x 6 TSSOP (PW) 8 19.2 mm² 3 x 6.4 VSSOP (DGK) 8 14.7 mm² 3 x 4.9 WSON (DRG) 8 9 mm² 3 x 3
  • Two-Channel Bidirectional Buffers
  • I2C Bus and SMBus Compatible
  • Active-High Repeater-Enable Input
  • Open-Drain I2C I/O
  • 5.5-V Tolerant I2C I/O and Enable Input Support Mixed-Mode Signal Operation
  • Lockup-Free Operation
  • Accommodates Standard Mode and Fast Mode I2C Devices and Multiple Masters
  • Powered-Off High-Impedance I2C Pins
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)

All trademarks are the property of their respective owners.

  • Two-Channel Bidirectional Buffers
  • I2C Bus and SMBus Compatible
  • Active-High Repeater-Enable Input
  • Open-Drain I2C I/O
  • 5.5-V Tolerant I2C I/O and Enable Input Support Mixed-Mode Signal Operation
  • Lockup-Free Operation
  • Accommodates Standard Mode and Fast Mode I2C Devices and Multiple Masters
  • Powered-Off High-Impedance I2C Pins
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)

All trademarks are the property of their respective owners.

This dual bidirectional I2C buffer is operational at 2.3-V to 3.6-V VCC.

The PCA9515A is a BiCMOS integrated circuit intended for I2C bus and SMBus systems applications. The device contains two identical bidirectional open-drain buffer circuits that enable I2C and similar bus systems to be extended without degradation of system performance.

The PCA9515A buffers both the serial data (SDA) and serial clock (SCL) signals on the I2C bus, while retaining all the operating modes and features of the I2C system. This enables two buses of 400-pF bus capacitance to be connected in an I2C application.

The I2C bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the PCA9515A enables the system designer to isolate two halves of a bus, accommodating more I2C devices or longer trace lengths.

The PCA9515A has an active-high enable (EN) input with an internal pullup, which allows the user to select when the repeater is active. This can be used to isolate a badly behaved slave on power-up reset. It never should change state during an I2C operation, because disabling during a bus operation hangs the bus, and enabling part way through a bus cycle could confuse the I2C parts being enabled. The EN input should change state only when the global bus and the repeater port are in an idle state, to prevent system failures.

The PCA9515A also can be used to run two buses: one at 5-V interface levels and the other at 3.3-V interface levels, or one at 400-kHz operating frequency and the other at 100-kHz operating frequency. If the two buses are operating at different frequencies, the 100-kHz bus must be isolated when the 400-kHz operation of the other bus is required. If the master is running at 400 kHz, the maximum system operating frequency may be less than 400 kHz, because of the delays that are added by the repeater.

The PCA9515A does not support clock stretching across the repeater.

The output low levels for each internal buffer are approximately 0.5 V, but the input voltage of each internal buffer must be 70 mV or more below the output low level, when the output internally is driven low. This prevents a lockup condition from occurring when the input low condition is released.

Two or more PCA9515A devices cannot be used in series. The PCA9515A design does not allow this configuration. Because there is no direction pin, slightly different valid low-voltage levels are used to avoid lockup conditions between the input and the output of each repeater. A valid low applied at the input of a PCA9515A is propagated as a buffered low with a slightly higher value on the enabled outputs. When this buffered low is applied to another PCA9515A-type device in series, the second device does not recognize it as a valid low and does not propagate it as a buffered low again.

The device contains a power-up control circuit that sets an internal latch to prevent the output circuits from becoming active until VCC is at a valid level (VCC = 2.3 V).

As with the standard I2C system, pullup resistors are required to provide the logic high levels on the buffered bus. The PCA9515A has standard open-collector configuration of the I2C bus. The size of these pullup resistors depends on the system, but each side of the repeater must have a pullup resistor. The device is designed to work with Standard Mode and Fast Mode I2C devices in addition to SMBus devices. Standard Mode I2C devices only specify 3 mA in a generic I2C system where Standard Mode devices and multiple masters are possible. Under certain conditions, high termination currents can be used.

This dual bidirectional I2C buffer is operational at 2.3-V to 3.6-V VCC.

The PCA9515A is a BiCMOS integrated circuit intended for I2C bus and SMBus systems applications. The device contains two identical bidirectional open-drain buffer circuits that enable I2C and similar bus systems to be extended without degradation of system performance.

The PCA9515A buffers both the serial data (SDA) and serial clock (SCL) signals on the I2C bus, while retaining all the operating modes and features of the I2C system. This enables two buses of 400-pF bus capacitance to be connected in an I2C application.

The I2C bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the PCA9515A enables the system designer to isolate two halves of a bus, accommodating more I2C devices or longer trace lengths.

The PCA9515A has an active-high enable (EN) input with an internal pullup, which allows the user to select when the repeater is active. This can be used to isolate a badly behaved slave on power-up reset. It never should change state during an I2C operation, because disabling during a bus operation hangs the bus, and enabling part way through a bus cycle could confuse the I2C parts being enabled. The EN input should change state only when the global bus and the repeater port are in an idle state, to prevent system failures.

The PCA9515A also can be used to run two buses: one at 5-V interface levels and the other at 3.3-V interface levels, or one at 400-kHz operating frequency and the other at 100-kHz operating frequency. If the two buses are operating at different frequencies, the 100-kHz bus must be isolated when the 400-kHz operation of the other bus is required. If the master is running at 400 kHz, the maximum system operating frequency may be less than 400 kHz, because of the delays that are added by the repeater.

The PCA9515A does not support clock stretching across the repeater.

The output low levels for each internal buffer are approximately 0.5 V, but the input voltage of each internal buffer must be 70 mV or more below the output low level, when the output internally is driven low. This prevents a lockup condition from occurring when the input low condition is released.

Two or more PCA9515A devices cannot be used in series. The PCA9515A design does not allow this configuration. Because there is no direction pin, slightly different valid low-voltage levels are used to avoid lockup conditions between the input and the output of each repeater. A valid low applied at the input of a PCA9515A is propagated as a buffered low with a slightly higher value on the enabled outputs. When this buffered low is applied to another PCA9515A-type device in series, the second device does not recognize it as a valid low and does not propagate it as a buffered low again.

The device contains a power-up control circuit that sets an internal latch to prevent the output circuits from becoming active until VCC is at a valid level (VCC = 2.3 V).

As with the standard I2C system, pullup resistors are required to provide the logic high levels on the buffered bus. The PCA9515A has standard open-collector configuration of the I2C bus. The size of these pullup resistors depends on the system, but each side of the repeater must have a pullup resistor. The device is designed to work with Standard Mode and Fast Mode I2C devices in addition to SMBus devices. Standard Mode I2C devices only specify 3 mA in a generic I2C system where Standard Mode devices and multiple masters are possible. Under certain conditions, high termination currents can be used.

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Technical documentation

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Type Title Date
* Data sheet PCA9515A Dual Bidirectional I2C Bus and SMBus Repeater datasheet (Rev. D) 12 Jun 2014
Application note Why, When, and How to use I2C Buffers 23 May 2018
Selection guide Logic Guide (Rev. AB) 12 Jun 2017
Application note Choosing the Correct I2C Device for New Designs PDF | HTML 07 Sep 2016
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) 02 Dec 2015
Application note Understanding the I2C Bus PDF | HTML 30 Jun 2015
Application note Maximum Clock Frequency of I2C Bus Using Repeaters 15 May 2015
Application note I2C Bus Pull-Up Resistor Calculation PDF | HTML 13 Feb 2015
Application note Troubleshooting I2C Bus Protocol 19 Oct 2009
Application note Programming Fun Lights With TI's TCA6507 30 Nov 2007
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection 08 Jul 2004

Design & development

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Simulation model

HSPICE Model for PCA9515A

SCEJ213.ZIP (216 KB) - HSpice Model
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TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
Package Pins Download
SOIC (D) 8 View options
TSSOP (PW) 8 View options
VSSOP (DGK) 8 View options
WSON (DRG) 8 View options

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