CMX983 Datasheet, PDF (63/93 Pages) CML Microcircuits – Programmable Channel Filter

Analogue Front End (AFE) for Digital Radio
CMX983
13 Auxiliary ADC and Comparators
AV_DD
2.5V
Threshold
adjust
Output invert/
latch
+
-
0
+
-
1
AUXCMP_ST_EN
AUXCMP_STAT
+
-
2
5
+
-
3
AUXCMP_CON0
AUXCMP_CON1
AUXCMP_CON2
+
-
4
AUXCMP_CON3
AUXCMP_CON4
Analogue Comparators
Analogue comparator status
Digital comparator status
AUXADC_STAT
8
Threshold
comparators
AUXADC_THR0
AUXADC_THR1
AUXADC_THR2
AUXADC_THR3
AUXADC_THR4
AUXADC_THR5
AUXADC_THR6
AUXADC_THR7
AUXADC0
AUXADC1
AUXADC2
AUXADC3
AUXADC4
AUXADC5
Sample/
Hold 1
Sample/
Hold 2
10-bit ¹⁰
ADC
AuxADCClk
AUXADC_DATA0
AUXADC_DATA1
AUXADC_DATA2
AUXADC_DATA3
AUXADC_DATA4
AUXADC_DATA5
AUXADC_DATA6
AUXADC_DATA7
AUXDAC7
(AUXADC6)
AUXDAC8
(AUXADC7)
Alternate
routing for
AuxADC
Channels 6
and 7
CLK
IQ
From input
gain stage
Clock div
÷2P
÷4^M ÷N
÷4^M ÷N
Timer
PwrUp
ADC
control
logic
End of convert status
AUXADC_CON
AUXADC_START
AUXADC_ABORT
AUXADC_CLK
AUXADC_PWRUP
Figure 25 Auxiliary ADC and Comparators
The Auxiliary ADC and Comparators circuit is shown in Figure 25. The auxiliary analogue to digital converter
is a 10-bit successive approximation ADC with eight multiplexed inputs. Six of the ADC inputs connect to
dedicated input pins and the remaining two inputs can be individually configured to connect to either the main
Rx channel I/Q gain stages, or to the AUXDAC7/8 pins. If using either of the AUXDAC7/8 pins as an ADC
input, the associated auxiliary DAC cannot be used and must be disabled. Each auxiliary ADC channel
includes a digital threshold comparator that can assert a status flag when any of the programmed threshold
levels have been exceeded.
There are five analogue comparators that share five of the ADC input signals. Each of these five inputs is
compared against an internal voltage threshold, and a separate flag is set when any of the programmed
threshold levels have been crossed.
 2015 CML Microsystems Plc
63
D/983/6