Monthly Archives: March 2018

Remote 8-bit I/O Expander for I²C-bus

PCA8574N Block Diagram

PCA8574N Block Diagram

PCA8574N is the remote 8-bit I/O expander for I²C-bus with interrupt. It provide general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus (serial clock (SCL), serial data (SDA)). It consist of eight quasi-bidirectional ports, 400kHz I²C‑bus interface, three hardware address inputs and interrupt output operating between 2.3 V and 5.5 V. The quasi-bidirectional port can be independently assigned as an input to monitor interrupt status or keypads, or as an output to activate indicator devices such as LEDs. The system master can read from the input port or write to the output port through a single register.

The low current consumption of 4.5 μA (typical, static) is great for mobile applications and the latched output ports have 25 mA high current sink drive capability for directly driving LEDs.

Why Used

  • Operating supply voltage 2.3 V to 5.5 V with 5.5 V tolerant I/Os held to VDD with 100 μA current source
  • 400 kHz I²C‑bus interface (Fast-mode I²C‑bus)
  • I²C‑bus to parallel port expander
  • 8-bit remote I/O pins that default to inputs at power-up
  • Latched outputs with 25 mA sink capability for directly driving LEDs

Where Used

  • Instrumentation and Test Measurement
  • Servers
  • LED Signs and Displays
  • PLCs
  • Industrial Control

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Low-voltage 16-bit I²C-bus I/O Port

PCA9555A Block Diagram

PCA9555A Block Diagram

PCA9555A is an NXP I/O expanders that provide a simple solution when additional I/Os are needed while keeping interconnections to a minimum. It is a low-voltage 16-bit General Purpose Input/Output (GPIO) expander with interrupt and weak pull-up resistors for I²C-bus/SMBus applications. The wide VDD range of 1.65 V to 5.5 V allows the PCA9555A to interface with next-generation microprocessors and microcontrollers where supply levels are dropping down to conserve power, considering the device provide a flexible set of GPIOs.

The device outputs have 25 mA sink capabilities for directly driving LEDs while consuming low device current. All input/outputs pins have weak pull-up resistors connected to them to eliminate external components.

Why Used

  • 5 V tolerant I/Os
  • I²C-bus to parallel port expander
  • Operating power supply voltage range of 1.65 V to 5.5 V
  • Low standby current consumption:
    • 1.5 μA (typical at 5 V VDD)
    • 1.0 μA (typical at 3.3 V VDD)
  • Schmitt-trigger action allows slow input transition and better switching noise immunity at the SCL and SDA inputs:
    • Vhys = 0.10 x VDD (typical)

Where Used

  • Sensors
  • LEDs
  • ACPI Power Switches
  • Fan Control
  • Push Buttons

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3.3 V, 2 Differential Channel, 2:1 Multiplexer/Demultiplexer Switch

CBTL02043A/CBTL02043B Block Diagram

CBTL02043A/CBTL02043B Block Diagram

This 2 differential channel, 2-to-1 multiplexer/demultiplexer switch allows expansion of existing high-speed ports for extremely low power. It can switch two differential signals to one of two locations.

The CBTL02043A has input and output pins on the opposite of the package, and is suitable for edge connector(s) with different signal sources on the motherboard. The CBTL02043B has outputs on both sides of the package, and the device can be placed between two connectors to multiplex differential signals from controller.

Why Used

  • High-speed signal switching for PCIe Gen3 8 Gbit/s
  • High bandwidth: 10 GHz at -3 dB
  • 2 bidirectional differential channel, 2 : 1 multiplexer/demultiplexer
  • Low return loss: -13.5 dB at 4 GHz
  • Low insertion loss:
    • -0.5 dB at 100 MHz
    • -1.3 dB at 4.0 GHz

Where Used

  • Routing of high-speed differential signals with low signal attenuation
    • PCIe Gen3
    • DisplayPort 1.2
    • USB 3.1
    • SATA 6 Gbit/s

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SuperSpeed USB 3.0 Redriver with PTN36241B

PTN36241B Block Diagram

PTN36241B Block Diagram

A SuperSpeed USB 3.0 redriver IC enhances signal quality by performing receive equalization on the deteriorated input signal followed by transmit de-emphasis maximizing system link performance. This is PTN36241B device that has superior differential signal conditioning and enhancement capability. It delivers significant flexibility and performance scaling for various systems with different PCB trace and cable channel conditions, and still benefit from optimum power consumption.

The PTN36241B has built-in advanced power management capability that enables significant power savings under various different USB 3.0 Low-power modes (U2/U3). It can detect LFPS signaling and link electrical conditions and can dynamically activate/de-activate internal circuitry and logic. The device performs these actions without host software intervention and conserves power.

Why Used

  • High-speed channel processing
    • Supports USB 3.0 specification (SuperSpeed only)
    • Support of 2 channels
    • Selectable receive equalization on each channel to recover from InterSymbol Interference (ISI) and high-frequency losses, with provision to choose from five Equalization gain settings per channel
  • Enhancements
    • Intelligent I2C-bus multiplexing and 5-level logic configuration options (with
      patent-pending quinary pins) delivering ultimate flexibility
    • I2C-bus interface:
      • Standard-mode (100 kbit/s) or Fast-mode (400 kbit/s)
      • 3.3 V tolerant

Where Used

  • USB 3.0 peripherals like consumer/storage devices, printers or USB 3.0 capable hubs/repeaters
  • Server and storage platforms
  • Notebook/netbook/nettop platforms
  • Docking stations
  • Desktop and AIO platforms

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