TPS7A4001: Operating below min operating temperature of -40 °C

Hi Lars,

I haven't heard of any behavior like this for this device. Can you provide some scope shots to help us better understand what is happening? If not can you explain what you mean when you say that it doesn't work or stops working?

-Kyle

Hello Kyle,

Thanks for your quick answer.
I have 4 LDOs on my board, and I could precisize the misbehaviour of the LDO as follows:

At a temperature below -43 °C the LDOs will not deliver the adjusted voltage of 14 V while the device is supplied by 28 V (I load approx 10 mA). Instead the device delivers a output votlage of ~ 1 V.

This effect occurs on power-up - this means the LDOs does not start-up below -43°C.

Note: I will continue detailed tests on this misbehavior. I have no scope plots because the device is in the temp chamber - I only could see no function of the circuit and my voltage monitoring of the LDO output voltage showed this ~1 V (The voltage monitoring is working fine).

1. Can you tell me up to what low-temperature the device is able to start-up? (I expected a power up at least down to -50°C)

2. Do you know anny my problem related issues with this device?

3. I have a redesign ongoing - so I can change this device. Can you recommend a similar device (100V / 50mA / adjustable LDO) where you can tell (no guarantee) that the device will start up at least at - 50°C ?

Note: I attached my schmetics.

Thanks in advance

Lars Hummel

LUA0089 - TPS7A4001.pdf

Lars,

Unfortunately the majority of our devices are only rated for -40C operation and so we don't have any that meet your 100V input and -50C operation.

Looking at your schematic I don't see an input capacitor, I assume that it is simply on another page of the layout. If not thie device requires at least 1uF of capacitance that is close to the input/gnd pins.