hello
I have a question about TCA9555 parts.
Can you tell me the amount of current consumed when the supply power is 3.3V or 5V?
Q1) When 3.3V is applied to Vcc, current consumption (Icc?) = ?
Q2) When 5.0V is applied to Vcc, current consumption (Icc?) = ?
Hi Jaehak,
ICC is widely dependent on your use case of the device. It is dependent on the mode you are operating in.
See this table in the electrical characteristics of the datasheet.
Depending on the state of the I/O pins, SCL frequency, loading, will determine different ICC spec's.
IF you are looking to see total ICC when driving different loads on the Pxx pins, this current will vary but would most likely be much larger than the values listed in the electrical characteristics since those were validated with no load.
Regards,
Tyler
Hi,
First of all, thank you for your reply.
I would like to ask again with a more detailed explanation.
We plan to control 64 TCA9555PWR parts.
Therefore, I asked you to review the current specifications.
This is an action concept. Please refer to the image.
-. We plan to control I/O Expanders TCA9555 64Qty with I2C Switch TCA9548 1Qty.
-. I2C Frequency is assumed to be 400[kHz]. (Actually, I don't think speed is important as low speed is sufficient.)
These are the operating conditions.
-. TCA9555(64Qty) is in I2C communication with TCA9548, and all I/O Pins of TCA9555(64Qty) are operating as input.
I have a question.
-. It is necessary to prepare for the cases with the highest current consumption when the supply power is 3.3[V] and 5.0[V].
Q1) What is the maximum current consumption of TCA9548 1Qty?
Case1) Vcc 3.3[V] = ?[mA]
Case2) Vcc 5.0[V] = ?[mA]
Q2) What is the maximum current consumption of TCA9555 1Qty?
Case1) Vcc 3.3[V] = ?[mA]
Case2) Vcc 5.0[V] = ?[mA]
Hi Jaehak,
I understand the application much better now.
This question is overall hard to pin point an exact value. Current through ICC will vary depending on how much current is passing through the TCA9548 i2c switch and how much current the TCA9555 IO expander is consuming. Since the TCA9555 units are being used as inputs for the p-ports, current should be less than an IO expander that is driving resistive loads on the output. ICC current will vary here because it is also dependent the the state whether HIGH or LOW on the input pin, and how many times the INPUT pin switches from HIGH to LOW and LOW to HIGH. These are high-impedance CMOS inputs that have a peak current draw somewhere in the middle of the VCC and GND.
This application is definitely had to quantify for the exact amount, but absolute maximum conditions can be taken into account to determine a maximum ICC needed by the supply if both the IO expander and switch operated at maximum capacity.
Q1) What is the maximum current consumption of TCA9548 1Qty?
At VCC = 3.3V, or 5.0V, ICC can withstand...
Q2) What is the maximum current consumption of TCA9555 1Qty?
At VCC = 3.3V or 5.0V, ICC can withstand...
These are absolute maximum conditions. I expect in actual application that the IO expander and switch would use much less current than these two values given.
Regards,
Tyler
