THCV217-THCV218_Rev.2.11_E

Copyright(C)2016 THine Electronics,Inc.

13

THine Electronics, Inc.

Security E

Lock Detect and Hot-Plug Function

LOCKN and HTPDN of Rx must be connected with those of Tx as in Figure 5.

LOCKN and HTPDN on THCV218 are both open drain outputs. Pull-up resistors are needed at Tx side.

If THCV218 is not active (in the power down mode, powered off, or not connected), THCV218’s HTPDN

turns high-Z, and the pull-up resister at the Tx side makes the HTPDN input of THCV217 high. THCV217 then

enters into the power down mode.

When THCV218 is active, HTPDN is pulled down by THCV218. Then THCV217 starts up and transmits the

“training pattern” for link training.

LOCKN indicates whether THCV218 is in the lock state or not. If THCV218 is not the lock state, LOCKN

turns high-Z. Otherwise (in the lock state), it’s pulled down by THCV218.

THCV217 keeps transmitting the “training pattern” until LOCKN turns low. And then THCV217 starts

transmitting serialized input data.

Figure 5. Hot-plug and Lock detect scheme

HTPDN connection between THCV217 and THCV218 can be omitted as an application option. In this case,

HTPDN at the Transmitter side should always be taken as Low. See Figure 6.

Figure 6. HTPDN is not connected scheme

Power supply for HTPDN

(Tx side)

Power supply for LOCKN

(Tx side)

HTPDN

LOCKN

THCV217

THCV218

10kΩ

10kΩ

Power supply for LOCKN

(Tx side)

HTPDN

LOCKN

THCV217

THCV218

HTPDN

10kΩ