AN2813 Datasheet, PDF (1/25 Pages) STMicroelectronics – TDE1708DFT in IO-Link applications

AN2813
Application note
TDE1708DFT in IO-Link applications
1
Introduction
This application note investigates the possibility of using a TDE1708DFT switch for the
physical layer transmitter realization of 3-wire IO-Link sensors.
The TDE1708DFT is an integrated power switch especially dedicated to proximity detectors.
It can deliver up to 250 mA, enables high-side and low-side configurations and includes
a number of protections.
According to the IO-Link Communication Specification (see Section 8: References -3. and
for the TDE1708DFT features - see Section 8: References - 1.) two basic slave transmitter
configurations were tested (see Figure 1):
■ p-switching (high-side) driver
■ p-switching driver with an additional n-switching (low-side) driver (push-pull operation)
Figure 1. P-switching slave drive and p-switching with n-switching slave drive
P SWITCHINGSLAVEDRIVE
SLAVE
LINE
, 
MASTER
P SWITCHINGWITHN SWITCHINGSLAVEDRIVER
SLAVE
LINE
,
MASTER
ON
OFF
#13
#1
),,-
#1-
ON
OFF
#1
ON
#13
OFF
),,-
#1-
,n
,n
!-
In the following test arrangements the input load current (ILL_M) is fixed to 10 mA which
represents the average master current sink value specified for a 3-wire system. The master
(CQ_M), slave (CQ_L), and line capacitances are set together at 4.7 nF, corresponding to the
maximum parasitic capacitance of the system.
February 2011
Doc ID 14923 Rev 1
1/25
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