Datasheet

MAXQ7667
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
DVDDIO
= +5V, V
AVDD
= +3.3V; V
DVDD
= +2.5V, system clock (f
SYSCLK
) = 16MHz, burst frequency (f
BURST
) = bandpass frequency
(f
BPF
) = 50kHz, C
REFBG
= C
REF
= 1µF in parallel with 0.01µF, f
ADCCLK
= 2MHz (SAR data rate = 125ksps), T
A
= T
MIN
to T
MAX
, unless
otherwise specified. Typical values are at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
REFERENCE BUFFER
Offset 5mV
Minimum Load 2.5 kΩ
Output Bypass Capacitor 0.47 µF
EXTERNAL VOLTAGE REFERENCE (Reference Buffer Disabled)
Reference Input Range Applied at REF 1.0 V
AVDD
V
Reference Input Impedance
Measured at REF with the SAR and
sigma-delta ADCs running at
maximum frequency
50 kΩ
INTERNAL VOLTAGE REFERENCE (REFBG)
Initial Accuracy 2.45 2.5 2.55 V
Maximum Temperature
Coefficient
100 ppm/°C
Output Impedance 1.1 kΩ
Power-Supply Rejection Ratio V
AVDD
= 3.0V to 3.6V 60 dB
Output Noise 0.5 mV
RMS
PROGRAMMABLE BURST-FREQUENCY OSCILLATOR
Burst-Frequency Range 0.025 1.335 MHz
Burst-Frequency Resolution 0.1 %
Change from 40kHz to 60kHz 5
Burst-Frequency Locking
Time
Change from 50kHz to 50.5kHz 2
ms
CRYSTAL OSCILLATOR
Tested crystal frequency 16
Minimum crystal frequency 4
Frequency Range
External clock input 4 16
MHz
Temperature Stability Excluding crystal 25 ppm/°C
Startup Time 16MHz crystal 10 ms
XIN Input Low Voltage When driven with external clock source
0.3 x
V
DVDD
V
XIN Input High Voltage When driven with external clock source
0.7 x
V
DVDD
V
INTERNAL RC OSCILLATOR
Frequency 13.5 MHz
Initial Accuracy 10.5 %
Temperature Drift T
A
= T
MIN
to T
MAX
700 ppm
Supply Rejection V
DVDD
= 2.25V to 2.75V -1.5 %