LTC3351 without Vin

Hi there,

I'm working with the DC2464A-B (with the LTC3351) demo board and Linduino DC2026.

It's working fine: with the PC GUI V1.2.9.0 I can access to all registers and they are updated continuously with the "AutoUpdateEnabled" button.

The problem comes when I unplug the power, I mean I unplug the Vin on the DC2464A-B; THEN the PC GUI is freeze and stop to update!!!!!

I have done some test:

->With Vin=25v:

On LTC3351: INTVCC=4.7V;  Vout=25V   ; vcc2p5=2,5V

On DC2026: Rx(D4) and Tx (D5) blinking continuously: On 0.3S, OFF 0.7S approximately.

On SMBus: ACK from the Slave device. (Verified with a sniffer)

On PC GUI: values updated constantly.

->With Vin unplugged:

On LTC3351: INTVCC=4.7V;  Vout=18.06V (boost working)  ; vcc2p5=2,5V

On DC2026: Rx(D4) and Tx (D5) blinking continuously: On 0.3S, OFF 0.7S approximately.

On SMBus: ACK from the Slave device. (Verified with a sniffer)

On PC GUI: values freezed!!!!!

I have sniffed the SMBus communication with a sniffer and apparently there is no difference, I can see the ACK bit in both cases. If you want I can send you some images.

Seems that without Vin the PC GUI is freeze; NEVERTHELESS the LTC3351 SMBus communications are working.

MY QUESTION IS:

Can you assert that the LTC3351 SMBus communications will work meanwhile its boost is working, and Vin is unplug?

Thanks