This 8-bit I/O expander for the two-line bidirectional bus (I2C) is designed for 2.3V to 5.5V VCC operation. The device provides general-purpose remote I/O expansion for most microcontroller families through the I2C interface [serial clock (SCL) and serial data (SDA)].
The PCA9557 consists of one 8-bit configuration (input or output selection), input port, output port, and polarity inversion (active-high) registers. At power on, the I/Os are configured as inputs. However, the system controller can enable the I/Os as either inputs or outputs by writing to the I/O configuration bits. The data for each input or output is kept in the corresponding input or output register. The polarity of the input port register can be inverted with the polarity inversion register. All registers can be read by the system controller.
The device outputs (latched) have high-current drive capability for directly driving LEDs. The device has low current consumption.
The system controller can reset the PCA9557 in the event of a timeout or other improper operation by asserting a low in the active-low reset (RESET) input. The power-on reset puts the registers in their default state and initializes the I2C/SMBus state machine. Asserting RESET causes the same reset/initialization to occur without depowering the part.
Three hardware pins (A0, A1, and A2) are used to program and vary the fixed I2C address, allowing up to eight devices to share the same I2C bus or SMBus.
| Documentación principal | Tipo | Título | Opciones de formato | Descargar la versión más reciente en inglés | Fecha |
|---|---|---|---|---|---|
| * | Hoja de datos | PCA9557 Remote 8-Bit I2 C and SMBus Low-Power I/O Expander With Reset and Configuration Registers datasheet (Rev. K) | PDF | HTML | 2/12/2024 | |
| Nota sobre la aplicación | Understanding Transient Drive Strength vs. DC Drive Strength in Level-Shifters (Rev. A) | PDF | HTML | 3/07/2024 | ||
| Nota sobre la aplicación | I2C Dynamic Addressing | 25/04/2019 | |||
| Nota sobre la aplicación | Choosing the Correct I2C Device for New Designs | PDF | HTML | 7/09/2016 | ||
| Nota sobre la aplicación | Understanding the I2C Bus | PDF | HTML | 30/06/2015 | ||
| Nota sobre la aplicación | Maximum Clock Frequency of I2C Bus Using Repeaters | 15/05/2015 | |||
| Nota sobre la aplicación | I2C Bus Pull-Up Resistor Calculation | PDF | HTML | 13/02/2015 |
Para conocer los términos adicionales o los recursos necesarios, haga clic en cualquier título de abajo para ver la página de detalles cuando esté disponible.
| Encapsulado | Pines | Símbolos CAD, huellas y modelos 3D |
|---|---|---|
| TSSOP (PW) | 16 | Ultra Librarian |
| VQFN (RGV) | 16 | Ultra Librarian |
| SSOP (DB) | 16 | Ultra Librarian |
| VQFN (RGY) | 16 | Ultra Librarian |
| SOIC (D) | 16 | Ultra Librarian |
| TVSOP (DGV) | 16 | Ultra Librarian |
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