Rainbow Electronics MAXQ7667 - Manual (Page 4)

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 5 mV
Minimum Load 2.5 k Ω
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 k Ω
INTERNAL VOLTAGE REFERENCE (REFBG)
Initial Accuracy 2.45 2.5 2.55 V
Maximum Temperature
Coefficient
100 ppm/°C
Output Impedance 1.1 k Ω
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 %