Datasheet

OE1
OE4
OE3
OE2
A1
A2
A3
A4
Y1
Y2
Y3
Y4
DBACK
DIN
ACKB
VAVD
COMACOMD
LOW
ERRLVL
C1
C2
C3
BASE
OUT
IN
OUT
GND
TPS79801
22P
22
40
40
1n
1n
100n
100n
20
100
300p
2.2n 2.2n 2.2n
74LVC125
DAC161P997
PRI_RX
PRI_TX
PRI_TX_EN
1k
IN
OUT
OUT
PC
1P
100n
LOOP+
LOOP-
Coilcraft
S5394
EN
FB
3.3P
100k
158k
4.1V
DAC161P997
SNAS515E –JULY 2011–REVISED OCTOBER 2013 www.ti.com
ERROR DETECTION AND REPORTING
The user can modify the CONFIG2:(LOOP | CHANNEL | PARITY | FRAME) bits to mask or enable the reporting
of any of the detectable fault conditions. The DAC161P997 reports errors by asserting the ERRB signal, and by
setting the current sourced by OUT to a value dictated by the state at ERRLVL pin and the contents of the
ERR_HIGH and ERR_LOW registers. Once the condition causing the fault is removed the OUT will return to the
last valid output level prior to the occurrence of the fault.
Table below summarizes the detectable faults, and means of reporting. The interval TM is governed by the
internal timer and is specified in ELECTRICAL CHARACTERISTICS.
REPORTING
ERROR CAUSE
Value used by the DAC to set OUT pin
ERRB
current
The device cannot sustain the required output current at
OUT pin, typically caused by drop in loop supply, or
increased load impedance.
LOOP LOW ERR_LOW
The DAC161P997 automatically clears this fault after
interval of TM and attempts to establish output current
dictated by the value in the DACCODE register
ERRLVL=1: ERR_HIGH
no valid symbols have been received on DIN in last
CHANNEL LOW
interval of TM
ERRLVL=0: ERR_LOW
ERRLVL=1: ERR_HIGH
SWIF received a valid data frame, but a bit error has
PARITY LOW
been detected by parity check
ERRLVL=0: ERR_LOW
ERRLVL=1: ERR_HIGH
invalid symbol received, or an incorrect number of valid
FRAME LOW
symbols were detected in the frame
ERRLVL=0: ERR_LOW
Application Circuit Examples
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