19-4598; Rev 1; 7/09
KIT
ATION
EVALU
BLE
AVAILA
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
General Description
Features
o
Smart Analog Peripherals
Dedicated Ultrasonic Burst Generator
Echo Receiving Path (Includes LNA, Sigma-
Delta ADC)
5-Channel, 12-Bit SAR ADC with 250ksps
Sampling Rate
Internal Bandgap Voltage Reference for the
ADCs (Also Accepts External Voltage Reference)
o
Timer/Digital I/O Peripherals
o
High-Performance, Low-Power, 16-Bit RISC Core
o
Program and Data Memory
o
Crystal/Clock Module
o
16 x 16 Hardware Multiplier with 48-Bit
Accumulator, Single Clock Cycle
o
Power-Management Module
o
JTAG Interface
o
Universal Asynchronous Receiver-Transmitter
(UART)
o
Local Interconnect Network (LIN)
See the
Detailed Features
section for complete list of features.
MAXQ7667
The MAXQ7667 smart system-on-a-chip (SoC) provides a
time-of-flight ultrasonic distance-measuring solution. The
device is optimized for applications involving large dis-
tance measurement with weak input signals or multiple
target identification. The MAXQ7667 features high signal-
to-noise ratio achieved by combining flexible electronics
with the intelligence necessary to optimize each function
as environmental and target conditions change.
An integrated burst signal generator and echo reception
components process ultrasonic signals between 25kHz
and 100kHz. Echo reception components include a pro-
grammable gain low-noise amplifier (LNA), a 16-bit
sigma-delta ADC to digitize the received echo signals,
and digital signal processing (DSP). DSP limits noise
with a bandpass filter, and creates an echo envelope
through demodulation and lowpass filtering. Input
referred noise is a low 0.7µV
RMS
. A programmable
phase-locked loop (PLL) frequency synthesizer supplies
the reference frequency for the burst generator and the
clock for the echo receiver’s digital filter. An embedded
16-bit MAXQ20 microcontroller (µC) controls all the pre-
ceding functions.
The µC optimizes the burst frequency and reception
frequency for each transmission at any temperature.
The MAXQ7667 achieves smart sensing by monitoring
the echo signals and then actively changing the trans-
mitted and received parameters to obtain optimum
results. Digital filtering and burst synthesis do not
require CPU intervention. This leaves all the CPU power
available for echo optimization, communication, diag-
nostics, and additional signal processing.
The MAXQ7667 operates with three different power
supply voltages: +5V, +3.3V, and +2.5V. Two internal
linear regulators allow operation from a single +5V sup-
ply when three external power supplies are not avail-
able. Alternatively, the MAXQ7667 can control an
external pass transistor to allow operation from a single
supply voltage of +8V to +65V or more, depending on
the external component tolerance. The device is avail-
able in a 48-pin LQFP package and is specified to
operate from -40°C to +125°C.
Ordering Information
PART
MAXQ7667AACM/V+
PIN-PACKAGE
48 LQFP
RAM
(KB)
4
FLASH
(KB)
32
Note:
All devices are specified over the -40°C to +125°C oper-
ating temperature range.
/V denotes an automotive qualified part.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Applications
Automotive Parking
Vehicle Security
Industrial Processing
Automation
Handheld Devices
Pin Configuration appears at end of data sheet.
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, go to:
ww.maxim-ic.com/errata.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
MAXQ7667
ABSOLUTE MAXIMUM RATINGS
DVDDIO, GATE5, REG3P3, REG2P5 to
DGND ................................................................-0.3V to +6.0V
AVDD to AGND .....................................................-0.3V to +4.0V
DVDD to DGND .....................................................-0.3V to +3.0V
DVDDIO to DVDD..................................................-0.3V to +6.0V
AVDD to DVDD......................................................-0.3V to +4.0V
AGND to DGND.....................................................-0.3V to +0.3V
Digital Inputs/Outputs to DGND..........-0.3V to (V
DVDDIO
+ 0.3V)
Analog Inputs/Outputs to AGND ............-0.3V to (V
AVDD
+ 0.3V)
XIN, XOUT to DGND ..............................-0.3V to (V
DVDD
+ 0.3V)
Maximum Current into Any Pin............................................50mA
Continuous Power Dissipation (T
A
= +70°C)
48-Pin LQFP (derate 21.7mW/°C above +70°C).....1739.1mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(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
Input-Referred Noise
(Note 1)
Minimum Detectable Signal
SYMBOL
CONDITIONS
VGA gain adjust = 1.55µV
P-P
/LSB
VGA gain adjust = 0.1µV
P-P
/LSB
VGA gain adjust = 1.55µV
P-P
/LSB
VGA gain adjust = 0.1µV
P-P
/LSB
VGA gain adjust = 1.55µV
P-P
/LSB,
unclipped
Operating Input Range
VGA gain adjust = 0.1µV
P-P
/LSB,
unclipped
VGA gain adjust
From echo input to = 1.55µV /LSB
P-P
bandpass filter in
VGA gain adjust
reply to input
= 0.1µV
P-P
/LSB
(Note 2)
6.7
1.55
µV
P-P
/LSB
0.1
10
150
80 x f
BPF
10 x f
BPF
16
R
IN
For each echo input
14
14
V
AVDD
/2
Recover from 2V
P-P
input
10
%
kHz
kHz
kHz
Bits
k
pF
V
µs
MIN
TYP
5.6
0.7
80
10
100
mV
P-P
MAX
UNITS
ECHO INPUT (Low-Noise Amplifier and Sigma-Delta ADC)
µV
RMS
µV
P-P
Programmable Gain
Programmable-Gain Adjust
Resolution
LNA Bandwidth
ADC Sampling Rate
ADC Output Data Rate
ADC Output Data Resolution
Echo-Input Resistance
Echo-Input Capacitance
Echo-Input DC Bias Voltage
Maximum Overvoltage
Recovery Time
2
_______________________________________________________________________________________
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
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
BANDPASS FILTER
Center Frequency
Passband Width
Minimum Stopband
Rejection
Output Data Rate
Output Data Resolution
LOWPASS FILTER
Corner Frequency
Rolloff
Output Data Rate
Output Data Resolution
SAR ADC
Resolution
Integral Nonlinearity
Differential Nonlinearity
Offset Error
Offset-Error Drift
Gain Error
Gain-Error Temperature
Coefficient
Input-Referred Noise
Differential Input Range
Absolute Input Range
Input Leakage Current
Conversion Time
Input Capacitance
Track-and-Hold Acquisition
Time
Turn-On Time
Conversion Clock
Conversion Rate
f
ADCCLK
f
ADCCLK
= 4MHz (not production
tested)
Three ADCCLK cycles at 2MHz
Eight ADCCLK cycles at 2MHz
0.5
13 ADCCLK cycles at 2MHz
14
1.5
4
4
250
At ADC inputs
Unipolar
Bipolar
0
-V
REF
/2
0
±0.1
6.5
±0.4
400
V
REF
+V
REF
/2
V
AVDD
Measurement
No missing codes
Tested at 125ksps
Tested at 125ksps
-2
±1
±5
±1
12
11
±1
±2
+2
±3
Bits
LSB
LSB
mV
µV/°C
%
ppmFS/°C
µV
RMS
V
V
µA
µs
pF
µs
µs
MHz
ksps
f
LPF
-3dB
0.1 x f
BPF
40
5 x f
BPF
16
kHz
dB/Decade
ksps
Bits
f
BPF
-3dB
One decade away from center
frequency
25
0.14 x f
BPF
-60
10 x f
BPF
16
100
kHz
kHz
dB
ksps
Bits
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAXQ7667
_______________________________________________________________________________________
3
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
MAXQ7667
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
REFERENCE BUFFER
Offset
Minimum Load
Output Bypass Capacitor
EXTERNAL VOLTAGE REFERENCE (Reference Buffer Disabled)
Reference Input Range
Reference Input Impedance
Applied at REF
Measured at REF with the SAR and
sigma-delta ADCs running at
maximum frequency
1.0
50
V
AVDD
V
kΩ
2.5
0.47
5
mV
kΩ
µF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
INTERNAL VOLTAGE REFERENCE (REFBG)
Initial Accuracy
Maximum Temperature
Coefficient
Output Impedance
Power-Supply Rejection Ratio
Output Noise
PROGRAMMABLE BURST-FREQUENCY OSCILLATOR
Burst-Frequency Range
Burst-Frequency Resolution
Burst-Frequency Locking
Time
CRYSTAL OSCILLATOR
Tested crystal frequency
Frequency Range
Temperature Stability
Startup Time
XIN Input Low Voltage
XIN Input High Voltage
INTERNAL RC OSCILLATOR
Frequency
Initial Accuracy
Temperature Drift
Supply Rejection
T
A
= T
MIN
to T
MAX
V
DVDD
= 2.25V to 2.75V
13.5
10.5
700
-1.5
MHz
%
ppm
%
Minimum crystal frequency
External clock input
Excluding crystal
16MHz crystal
When driven with external clock source
When driven with external clock source
0.7 x
V
DVDD
4
25
10
0.3 x
V
DVDD
16
4
16
ppm/°C
ms
V
V
MHz
Change from 40kHz to 60kHz
Change from 50kHz to 50.5kHz
0.025
0.1
5
2
1.335
MHz
%
ms
V
AVDD
= 3.0V to 3.6V
2.45
2.5
100
1.1
60
0.5
2.55
V
ppm/°C
kΩ
dB
mV
RMS
4
_______________________________________________________________________________________
16-Bit, RISC, Microcontroller-Based,
Ultrasonic Distance-Measuring System
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
Adjustable Frequency Range
Frequency Adjustment
Resolution
SUPPLY VOLTAGE SUPERVISORS
DVDD Reset Threshold
DVDD Interrupt Threshold
Minimum Reset and Interrupt
Threshold Difference
AVDD Interrupt Threshold
DVDDIO Interrupt Threshold
Supervisor Operating Range
Supervisor Hysteresis
RESET
Release Delay
After V
DVDD
rises above the reset
threshold
Time from
RESET
is released to the
execution of the first instruction (serial
bootloader off)
Generates an interrupt if V
AVDD
falls
below this threshold
Generates an interrupt if V
DVDDIO
falls
below this threshold
At DVDD
Asserts
RESET
if V
DVDD
falls below
this threshold
Generates an interrupt if V
DVDD
falls
below this threshold
2.10
2.25
150
2.95
4.5
1.5
1
35
3.15
4.75
2.75
2.25
2.38
V
V
mV
V
V
V
%
µs
SYMBOL
CONDITIONS
Using the RCTRM register
MIN
-40
0.2
TYP
MAX
+40
UNITS
%
%
MAXQ7667
Power-Up Time
1
µs
+5V LINEAR REGULATOR (DVDDIO, GATE5, Requires External Pass Transistor, see the
Typical Application
Circuit/Functional Diagram)
Regulator Output Voltage
GATE5 Output High Voltage
GATE5 Output Low Voltage
GATE5 Output Resistance
Gain Bandwidth
Gain
GATE5 Slew Rate
Maximum Load Capacitance
+3.3V LINEAR REGULATOR (REG3P3)
REG3P3 Output Voltage
Load Current
Output Short-Circuit Current
REG3P3 shorted to AGND
150
3.15
3.45
50
V
mA
mA
Maximum capacitance on DVDDIO
when using an external pass transistor
At DVDDIO
I
SOURCE
= 0µA (no load)
I
SINK
= 500µA
I
SINK
= 0µA to 50µA
DVDDIO to GATE5
DVDDIO to GATE5
330
1.58
1700
4.3
1
4.75
V
DVDDIO
- 0.1
2
5.25
V
V
V
Ω
kHz
V/V
V/ms
µF
_______________________________________________________________________________________
5
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