TPS22963C: tR min value and behavior of changing reverse protection mode to normal operation

Hello, 

(1) Rise time is a very use-case specific parameter meaning it will vary based on your loading conditions. 

If you have a specific loading condition, we can test this parameter in lab and apply min and max values based on simulation data. 

(2) I cannot find the device you are referring to with regard to "TLV74218" could you link me to the product page to which you are referring?

We do offer several dedicated power mux devices that allow you to select between two power sources synchronously or asynchronously. 

For more information on our power mux portfolio please visit: https://www.tij.co.jp/ja-jp/power-management/power-switches/power-muxes/products.html

Best Regards, 

Elizabeth 

Hello, thank you for your reply.

(1) Loading condition is about 100mA.

(2) TLV74218 link is following.

https://www.ti.com/store/ti/en/p/product/?p=TLV74218PDQNR

Thanks.

Hello, 

Could you specify your Cin, Cout, and Rout on the TPS22963C?

Best Regards, 

Elizabeth

Hello,

Condition is followings.

Cin=47uF x2 (=12V to 3.3V DCDC's Cout)

Cout=1uF+2.2uF

Rout=33 ohm (max 100mA)

Ta = 0 ~ 70℃

I need to satisfy "slew rate < 18mV/us" in rising.

(0V to 3.3V Rise time must be longer than 183.33us.) 

datasheet tR Typ: 715us > 183.33us . It is OK.

I want to know tR Min > 183.33us satisfy or not.

Best Regards.

Hi Yama,

Apologies for the delay; I was looking through some characterization data to see if we had anything else to provide on hand.
Since we do not specify this parameter, this request is going to require a combined design-applications effort to support the min value.
Our plan is to use an EVM operating in nominal condition, collect rise time values, and provide min-max values based on simulation data.
I have reached out to design to get a better estimate on the expected timeline. 

Best Regards, 

Elizabeth 

Hi, thank you for your support.

How about (2) question?

Do you think TPS22963C operate normally?

(3.3V output and 1.8V output are cotrolled by EN_SW on my shcematic.)

Best Regards.

Hello,

Alternative to our integrated power mux products, with regard to power muxing solutions, we recommend two load switch devices that have reverse current blocking and no quick output discharge.  

The EN signal used for one device will pass through a inverter and then is used to control the second device.

Alternatively another method of control is to use a MCU with two outputs and tuns on/off one device waits, for a slight delay and then turns on/off the second device to avoid any channel to channel conduction.

In load switch muxing, you use the reverse current protection to turn off the device during switching. 

Without reverse current protection which does not appear present in the LDO device, reverse current has the potential to flow through the body diode of your LDO whenever the output is greater than the input such as in which can cause damage explained further in this E2E blog: 

https://e2e.ti.com/blogs_/b/powerhouse/posts/ldo-basics-preventing-reverse-current-in-ldos

With output discharge present in the LDO, if using the 'P' part, the output will discharge whenever EN is low for the TLV74218P device even if the TPS22963C is sending out an output such as in case 2. This will cause a huge power loss on TLV74218P.

In a powerMUX however, there is a seperate switching circuit that handles these cases and protects against the backflow of current by waiting for the output to drop below the input before turning on the channel. 

Best Regards, 

Elizabeth 

Hello, thank you for your reply.

We used TPS22914C and TLV74218 for Power MUX on our past product.
However, I need to change TPS22914C, because 0.4mm pin pitch is not good for our next product.
So, I think changing TPS22914C to TPS22963C.
TPS22963C is 0.5mm pitch, and its rise time (=tR) is OK (>183.33us).
I want to change TPS22914C to other load switch simply.
Could you let me know my (2) question?
I want to know TPS22963C operates nomally or not.

Best Regards.

Hello Yama,

TPS22963C when disabled will keep reverse current flow less than 0.02uA. Using this device to mux will be fine as long as you've confirmed your timing requirements; however, I can't speak for the TLV device operation. You will have constant power loss due to QOD functionality of the TLV device when 63C device is powering the load. 

Elizabeth has placed your timing request into the design queue. This usually takes about 3 weeks to a month to turn-around. She will update you as soon as she gets the data back.

Regards,

Kalin Burnside

Hello

Sure, thank you for your support.
Best Regards.