LTM8052 shutdown output high impedance?

Question

I would like to know when LTM8052 module is shutdown, what is the mode of Vout pins. Are they in high impedance mode? If there is a external voltage there, will there be any leakage current from LTM Vout pins. If any, how much will that be? Thanks.

gina_l · Accepted Answer

Hello Victor, 
 Depending on the application, there will be some amount of leakage current from the following paths: 
 1) From the top internal feedback resistor (10k ohm) through the external bottom feedback resistor (It is the resistor from ADJ pin to GND) . This leakage current varies depending on selected VOUT. It is negligible at 1.2Vout, roughly ~30uA at 1.5Vout up to <2.5mA at 24Vout (These are approximations at room temp) 
 2) From the top internal FB resistor (10kohm) through the ADJ pin and the Voltage Regulator Amp. (This is very small and negligible) 
 3) From VOUT to SW node to GND (This is negligible as well, but increases a bit with Vout and ambient temp) 
 *NOTE 1: Do not allow VIN to be less than VOUT since the top FET&rsquo;s body diode will cause a low impedance path from VOUT to VIN. 
 *NOTE 2: All the above numbers are only estimated and can not be guaranteed. 
 * To estimate the current going through VOUT pin(s) with external voltage applied at VOUT pin (s) when it is shutdown, you can download the LTspice demo board circuit of this part from the below link, modify this circuit to match with your test conditions, simulate the circuit, then measure current going into VOUT pin(s) of the part. You can also order a demo board to evaluate and verify your design. 
 https://www.analog.com/en/products/ltm8052.html#product-overview 
 Thanks, 
 Best Regards)

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LTM8052 shutdown output high impedance?

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