Dual SPM Detector
Page 4 of 16
MX641 Preliminary Information
2. Signal List
Pin
No.
Name
Type
Description
1
Xtal/Clock
input
The input to the on-chip clock oscillator; for use with a 3.579545MHz
Xtal in conjunction with the Xtal output; circuit components are on-chip.
When using a Xtal input, the Clock Out pin should be connected directly
to the Clock In pin. If a clock pulse input is used at the Clock In pin, this
(Xtal/Clock) pin must be connected directly to V (see Figure 2). See
DD
Figure 3 for details of clock frequency distribution.
2
3
output The output of the on-chip clock oscillator inverter.
XTAL
Clock Out
output The buffered output of the on-chip-clock oscillator inverter. If a Xtal
input is used, this output should be connected directly to the Clock In
pin. This output can support up to 3 additional MX641 ICs. See Figure
3 for details of clock frequency distribution.
4
5
Clock In
input
The 3.579545 clock pulse input to the internal clock dividers. If an
externally generated clock pulse input is used, the Xtal/Clock input pin
should be connected to V
.
DD
input For multi-chip output multiplexing; controls the state of both Ch1 and
Ch2 outputs. When this input is placed high (logic '1') both outputs are
set to a high impedance. When placed low (logic '0') both outputs are
enabled.
Output Enable
6
7
8
Ch 2 Output
Ch 1 Output
output The digital output of the Channel 2 SPM detector when enabled. The
format of the signal at this pin, in common with Ch 1, is selectable to
either 'Tone Follower' or 'Packet' mode via the Output Select input.
output The digital output of the Channel 1 SPM detector when enabled. The
format of the signal at this pin, in common with Ch 2, is selectable to
either 'Tone Follower' or 'Packet' mode via the Output Select input.
V
BIAS
power The output of the on-chip analog bias circuitry. Held internally at V /2,
DD
this pin should be decoupled to V (see Figure 2).
SS
9
Ch 1 Amp Out
output The output of the Channel 1 Input Amplifier. See Figure 2 and Figure 8.
10
Ch 1 Amp In (-): input The negative input to the Channel 1 Input Amplifier. See Figure 2 and
Figure 8.
11
12
Ch 1 Amp In
(+):
input The positive input to the Channel 1 Input Amplifier. See Figure 2 and
Figure 8.
V
SS
power Negative supply (GND).
13
14
N/C
No internal connection; leave open circuit.
Ch 2 Amp In
(+):
input The positive input to the Channel 2 Input Amplifier. See Figure 2 and
Figure 8.
15
Ch 2 Amp In (-): input The negative input to the Channel 2 Input Amplifier. See Figure 2 and
Figure 8.
16
17
Ch 2 Amp Out
Output Select
output The output of the Channel 2 Input Amplifier. See Figure 2 and Figure 8.
input A logic input to set the Channel 1 and Channel 2 output modes. When
high (logic '1'), the outputs are in the Tone Follower mode; when low
(logic '0'), the outputs are in the Packet mode.
18
Preset Level
input A logic input to set the sensitivity mode of the MX641. When high (logic
'1'), both channels are in the Fixed Sensitivity mode. The external
components govern the input sensitivity; the System Select input
selects 12kHz or 16kHz operation. When low (logic '0'), both channels
are in the Controlled Sensitivity mode. Device sensitivities and system
selection are via the Chip Select/Serial Data/Serial Clock inputs. This
input has an internal pull-up resistor on chip (Fixed Sensitivity Mode).
ã 2001 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480115.004
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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