Rainbow Electronics MAXQ7667 - Manual (Page 9)

MAXQ7667
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
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BURST OUTPUT FREQUENCY
vs. TEMPERATURE
MAXQ7667 toc01
TEMPERATURE ( °C)
BURST OUTPUT FREQUENCY (kHz)
50 25 100 75 0 -25
49.96
49.97
49.98
49.99
50.00
50.01
50.02
50.03
50.04
50.05
49.95
-50 125
USING PLL
LOWPASS FILTER OUTPUT
vs. ECHO INPUT AMPLITUDE
MAXQ7667 toc02
ECHO INPUT AMPLITUDE (V P-P )
LPF OUTPUT (LSB)
0.04 0.02 0.08 0.06
24,576
32,768
8192
16,384
40,960
49,152
57,344
65,536
0
0 0.10
PROGRAMMABLE ECHO GAIN = MINIMUM
LOWPASS FILTER OUTPUT
vs. ECHO INPUT FREQUENCY
MAXQ7667 toc03
ECHO INPUT FREQUENCY (kHz)
LPF OUTPUT (LSB)
55 40 85 70
1000
100
10,000
100,000
10
25 100
PROGRAMMABLE ECHO GAIN = MINIMUM
ECHO INPUT AMPLITUDE = 20mV
P-P
BANDPASS FILTER OUTPUT NOISE FLOOR
vs. BANDPASS FILTER CENTER FREQUENCY
MAXQ7667 toc04
FREQUENCY (kHz)
BANDPASS FILTER OUTPUT (LSB
RMS
)
80 60 40
9
3
6
12
15
0
20 100
RECEIVE PATH GAIN AT MAXIMUM
T A = +105 °C
T A = +25 °C
T A = -40 °C
RECEIVE PATH RESPONSE TIME
(ECHO INPUT TO LOWPASS FILTER OUTPUT)
MAXQ7667 toc05
TIME ( µs)
ADC COUNT (LSB)
400 200 800 600
6000
4000
10,000
2000
8000
14,000
12,000
16,000
0
0 1000
MINIMUM ECHO GAIN
20mV P-P ECHO AMPLITUDE
50kHz ECHO FREQUENCY
250ksps
INPUT ON
INPUT OFF
LOWPASS FILTER OUTPUT RIPPLE vs. TIME
MAXQ7667 toc06
TIME (ms)
LPF OUTPUT (LSB)
2 4 6 10 8
12,500
12,000
14,500
11,500
14,000
10,500
13,000
11,000
13,500
15,000
10,000
0 12
MINIMUM ECHO GAIN
20mV
P-P ECHO AMPLITUDE
50kHz ECHO FREQUENCY
250ksps
SAR ADC OFFSET ERROR
vs. TEMPERATURE
MAXQ7667 toc07
TEMPERATURE ( °C)
OFFSET ERROR (mV)
0 75 25 -25 100 50
0.5
-0.5
0
1.0
1.5
2.0
-1.0
-50 125
V AVDD = 3.3V
V AVDD = 3.6V
V AVDD = 3V
Typical Operating Characteristics
(V DVDDIO = +5V, V AVDD = +3.3V, V DVDD = +2.5V, f SYSCLK = 16MHz, burst frequency = bandpass frequency = 50kHz, T A = +25°C,
unless otherwise noted.)