HCPL-0872 Datasheet, PDF (12/12 Pages) AVAGO TECHNOLOGIES LIMITED – Digital Interface IC

Adjustable Threshold Detection
Table 6. Threshold Level Configuration.
The adjustable threshold detector causes the THR1 output
to go high when the magnitude of the input signal on
channel 1 exceeds a user-defined threshold level. The
threshold level can be set to one of 16 different values
between approximately 160 mV and 310 mV. The adjust-
able threshold detector uses a smaller version of the main
conversion circuit in combination with a digital compara-
tor to detect when the magnitude of the input signal on
channel 1 is beyond the defined threshold level. As with
the main conversion circuit, there is a trade-off between
speed and resolution with the threshold detector;
selecting faster detection times exhibit more noise as
the signal passes through the threshold, while slower
detection times offer lower noise. Both the detection
time and threshold level are programmable using bits 2
through 7 of configuration register 2, as shown in Tables
5 and 6 below.
As with the over-range detector, the adjustable threshold
detector continuously monitors channel 1 independent
of which channel is selected with the CHAN signal. This
allows continuous monitoring of channel 1 for faults
while converting Channel 2.
Table 5. Threshold Detection Configuration.
Threshold
Detection
Time
Configuration Data Bits
Bit 7
Bit 6
2 - 6 µs
Low
Low
3 - 10 µs
Low
High
Threshold
Level
Configuration Data Bits
Bit 5 Bit 4 Bit 3
±160 mV
Low Low Low
± 170 mV
Low Low
± 180 mV
± 190 mV
High
± 200 mV
± 210 mV
± 220 mV
± 230 mV
Low
Low
High
High
± 240 mV
± 250 mV
± 260 mV
± 270 mV
± 280 mV
± 290 mV
± 300 mV
± 310 mV
High
Low
High
Low
High
Low
High
Notes: Bold italic type indicates Default values.
Bit 2
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
Low
High
5 - 20 µs
High
Low
10 - 35 µs
High
High
Notes: Bold italic type indicates Default values.
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Data subject to change. Copyright © 2006 Avago Technologies Limited. All rights reserved. Obsoletes 5989-2165EN
AV02-0411EN - May 14, 2007
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