Analog Devices Inc./Maxim Integrated

12V, 120mA Flash Memory Programming Supply

The MAX7347/MAX7348/MAX7349 I²C interfaced peripherals provide microprocessors with management of up to 64 key switches. Key inputs are monitored statically, not dynamically scanned, to ensure low-EMI operation. The MAX7347 can monitor up to 24 switches, the MAX7348 can monitor up to 40 switches, and the MAX7349 can monitor up to 64 switches. The switches can be metallic or resistive (carbon) up to 1kΩ.The key controller debounces and maintains a FIFO of key-press events (including autorepeat, if enabled). An interrupt (active-low INT) output can be configured to alert key presses either as they occur, or at maximum rate. The MAX7348/MAX7349 feature a tone generator to generate automatic key-click sounds or alarm tones under processor control.The sounder frequencies cover the 5th musical octave (523.25Hz to 987.77Hz), plus seven other musical notes up to 2637Hz. The output can also be programmed to be high or low for the sound duration to operate an electronic sounder, relay, or lamp.The MAX7347 is offered in 16-pin QSOP and TQFN packages. The MAX7348 is offered in a 20-pin QSOP package. The MAX7349 is available in 24-pin QSOP and TQFN packages. The MAX7347/MAX7348/MAX7349 operate over the -40°C to +125°C temperature range.ApplicationsIndustrial ControlsInstrumentation PanelsMedical InstrumentsSecurity and Access

The MAX7356/MAX7357/MAX7358 8-channel I²C switches/multiplexers expand the main I²C bus to any combination of 8 extended I²C buses. They enable a master on the main bus to isolate and communicate with devices or groups of devices that may otherwise have slave address conflicts. Any extended bus can be connected or disconnected by control packets from the main I²C bus writing to the main control register of these I²C switches.The MAX7357 and MAX7358 feature an enhanced mode that includes a built-in timer used to monitor all extended buses for lock-up conditions. If the clock or data line of any of these buses is low for more than 25ms (typ), a lock condition is detected. An optional interrupt can be generated through the bidirectional active-low RST/active-low INT. The master can read the bus lock-up register to find out which extended bus is locked up. The master can also enable the MAX7357 or the MAX7358 to send a "flush-out" sequence on the faulty channel. There is an optional preconnection check that can be enabled to toggle the extended bus clock and data line low then high to ensure the downstream bus is not locked high prior to connecting it to the host bus.The MAX7356/MAX7357/MAX7358 are transparent to signals sent and received at each channel, allowing multiple masters. Any device connected to an I²C bus can transmit and receive signals; however, only the master connected to the host side of the MAX7356/MAX7357/MAX7358 should address the device.The MAX7356/MAX7357/MAX7358 are available in 24-pin TSSOP and TQFN packages and are specified over the extended -40°C to +85°C temperature range.ApplicationsBase StationsControl and Automation DevicesNetworking EquipmentRAIDServersSFP Control Interface