这个用于两线双向总线 (I2C) 的 16 位扩展器设计用于在 2.3V 至 5.5V VCC 之间运行。通过 I2C 接口 [串行时钟 (SCL)，串行数据 (SDA)]，它为大多数微控制器系列产品提供通用远程 I/O 扩展。 PCA9539 由两个 8 位配置（输入或输出可选）、输入端口、输出端口和极性反转（高电平有效或低电平有效运行）寄存器组成。在加电时，I/O 被配置为输入。系统主控制器可以通过写入 I/O 配置位将 I/O 启用为输入或输出。每个输入或输出的数据均保存在相应的输入或输出寄存器中。输入端口寄存器的极性可借助极性反转寄存器进行转换。所有寄存器都可由系统主控器读取。 The system master can reset the PCA9539 in the event of a time-out or other improper operation by asserting a low in the 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 de-powering the part. The PCA9539 open-drain interrupt (INT) output is activated when any input state differs from its corresponding Input Port register state and is used to indicate to the system master that an input state has changed. INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I²C bus. Thus, the PCA9539 can remain a simple slave device. The device outputs (latched) have high-current drive capability for directly driving LEDs. The device has low current consumption. The PCA9539 is identical to the PCA9555, except for the removal of the internal I/O pullup resistor, which greatly reduces power consumption when the I/Os are held low, replacement of A2 with RESET, and a different address range. Two hardware pins (A0 and A1) are used to program and vary the fixed I²C address and allow up to four devices to share the same I²C bus or SMBus.

	属性	参数值
	商品目录	I/O扩展器
	接口类型	I2C；SMBus
	I/O数量	16
	是否有中断输出	有中断输出
	输出类型	推挽式
	工作电压	2.3V~5.5V
	灌电流(IOL)	25mA

	属性	参数值
	拉电流(IOH)	10mA
	时钟频率(fc)	400kHz
	工作温度	-40℃~+85℃
	支持设备数量	4
	静态电流(Iq)	1.5uA
	输出高电平(VOH)	2.6V
	输出低电平(VOL)	500mV

PCA9539DBQR

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