General description

      The AT9515A is a CMOS integrated circuit intended for application in I²C-bus and  SMBus systems.

      While retaining all the operating modes and features of the I²C-bus system, it permits extension of the I²C-bus by buffering both the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF.

      The I²C-bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the AT9515A enables the system designer to isolate two halves of a bus, thus more devices or longer length can be accommodated. It can also be used to run two buses, one at 5 V and the other at 3.3 V or a 400 kHz and 100 kHz bus, where the 100 kHz bus is isolated when 400 kHz operation of the other is required.

     Two or more AT9515As cannot be put in series. The AT9515A design does not allow this configuration. Since there is no direction pin, slightly different ‘legal’ low voltage levels are used to avoid lock -up conditions between the input and the output. A ‘regular LOW’ applied at the input of a AT9515A will be propagated as a ‘buffered LOW’ with a slightly higher value. When this ‘buffered LOW’ is applied to another AT9515A, AT9516A or AT9518/A in series, the second AT9515A, AT9516A or AT9518/A will not recognize it as a ‘regular LOW’ and will not propagate it as a ‘buffered LOW’ again. The AT9510/A, AT9511/A, AT9512/A, AT9513/A, AT9514/A cannot be used in series with the AT9515A, AT9516A or AT9518/A, but can be used in series with themselves since they use shifting instead of static offsets to avoid lock-up conditions.

    The output pull-down of each internal buffer is set for approximately 0.5V, while the input threshold of each internal buffer is set about 0.07 V lower, when the output is internally driven LOW. This prevents a lock-up condition from occurring.

Features

    2-channel, bidirectional buffer

    I²C-bus and SMBus compatible 

    Active HIGH repeater enable input 

    Open-drain input/outputs 

    Lock-up free operation

    Supports arbitration and clock stretching across the repeater 

    Accommodates Standard-mode and Fast-mode I²C-bus devices and multiple masters

    Powered-off high-impedance I²C-bus pins

    Operating supply voltage range of 2.3 V to 3.6 V 

    5.5 V tolerant I²C-bus and enable pins

    0 Hz to 400 kHz clock frequency (the maximum system operating frequency may be less than 400 kHz because of the delays added by the repeater) 

    ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101 

    Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA 

    Packages offered: SO8, TSSOP8 (MSOP8), HWSON8

Functional diagram