ADS8321
DESCRIPTION
The ADS8321 is a 16-bit sampling analog-to-digital
converter with guaranteed specifications over a 4.75V
to 5.25V supply range. It requires very little power
even when operating at the full 100kHz data rate. At
lower data rates, the high speed of the device enables
it to spend most of its time in the power-down mode--
the average power dissipation is less than 1mW at
10kHz data rate.
The ADS8321 also features a synchronous serial
(SPI/SSI compatible) interface, and a differential in-
put. The reference voltage can be set to any level
within the range of 500mV to 2.5V.
Ultra-low power and small size make the ADS8321
ideal for portable and battery-operated systems. It is
also a perfect fit for remote data acquisition mod-
ules, simultaneous multi-channel systems, and iso-
lated data acquisition. The ADS8321 is available in
an 8-lead MSOP package.
16-Bit, High Speed, MicroPower Sampling
ANALOG-TO-DIGITAL CONVERTER
1999 Burr-Brown Corporation
PDS-1537A
Printed in U.S.A. Setpember, 1999
FEATURES
q
BIPOLAR INPUT RANGE
q
100kHz SAMPLING RATE
q
MICRO POWER:
4.5mW at 100kHz
1mW at 10kHz
q
POWER DOWN: 3
A max
q
8-LEAD MSOP PACKAGE
q
PIN-COMPATIBLE TO ADS7816 AND
ADS7822
q
SERIAL (SPI/SSI) INTERFACE
APPLICATIONS
q
BATTERY OPERATED SYSTEMS
q
REMOTE DATA ACQUISITION
q
ISOLATED DATA ACQUISITION
q
SIMULTANEOUS SAMPLING,
MULTI-CHANNEL SYSTEMS
q
INDUSTRIAL CONTROLS
q
ROBOTICS
q
VIBRATION ANALYSIS
International Airport Industrial Park Mailing Address: PO Box 11400, Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 Tel: (520) 746-1111
Twx: 910-952-1111 Internet: http://www.burr-brown.com/ Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
For most current data sheet and other product
information, visit www.burr-brown.com
SAR
Serial
Interface
Comparator
ADS8321
S/H Amp
DCLOCK
D
OUT
CS/SHDN
+In
V
REF
In
CDAC
2
ADS8321
SPECIFICATIONS: +V
CC
= +5V
At 40
C to +85
C, V
REF
= +2.5V, In = 2.5V, f
SAMPLE
= 100kHz, and f
CLK
= 24 f
SAMPLE
, unless otherwise specified.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN
assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user's own risk. Prices and specifications are subject
to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not
authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.
ADS8321E
ADS8321EB
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
RESOLUTION
16
T
Bits
ANALOG INPUT
Full-Scale Input Span
+In (In)
V
REF
+V
REF
T
T
V
Absolute Input Range
+In
0.1
V
CC
+ 0.1
T
T
V
In
0.1
+4.0
T
T
V
Capacitance
25
T
pF
Leakage Current
1
T
nA
SYSTEM PERFORMANCE
No Missing Codes
14
15
Bits
Integral Linearity Error
0.008
0.018
0.006
0.012
% of FSR
Offset Error
0.4
2
0.2
1
mV
Offset Temperature Drift
1
T
V/
C
Gain Error, Positive
0.05
0.024
%
Negative
0.05
0.024
%
Gain Temperature Drift
0.3
T
ppm/
C
Noise
60
T
Vrms
Common-Mode Rejection Ratio
80
T
dB
Power Supply Rejection Ratio
+4.7V < V
CC
< 5.25V
3
T
LSB
(1)
SAMPLING DYNAMICS
Conversion Time
16
T
Clk Cycles
Acquisition Time
4.5
T
Clk Cycles
Throughput Rate
100
T
kHz
Clock Frequency Range
0.024
2.9
T
T
MHz
DYNAMIC CHARACTERISTICS
Total Harmonic Distortion
V
IN
= 5Vp-p at 10kHz
84
86
dB
SINAD
V
IN
= 5Vp-p at 10kHz
82
84
dB
Spurious Free Dynamic Range
V
IN
= 5Vp-p at 10kHz
84
86
dB
SNR
85
87
dB
REFERENCE INPUT
Voltage Range
0.5
V
CC
/2
T
T
V
Resistance
CS = GND, f
SAMPLE
= 0Hz
5
T
G
CS = V
CC
5
T
G
Current Drain
40
80
T
T
A
f
SAMPLE
= 10kHz
0.8
T
A
CS = V
CC
0.1
3
T
A
DIGITAL INPUT/OUTPUT
Logic Family
CMOS
T
Logic Levels:
V
IH
I
IH
= +5
A
3.0
V
CC
+ 0.3
T
T
V
V
IL
I
IL
= +5
A
0.3
0.8
T
T
V
V
OH
I
OH
= 250
A
4.0
T
V
V
OL
I
OL
= 250
A
0.4
T
V
Data Format
T
POWER SUPPLY REQUIREMENTS
V
CC
Specified Performance
4.75
5.25
T
T
V
V
CC
Range
(2)
2.7
5.25
T
T
V
Quiescent Current
1100
1700
T
T
A
f
SAMPLE
= 10kHz
(3, 4)
250
T
A
Power Dissipation
5.5
8.5
T
T
mW
Power Down
CS = V
CC
0.3
3
T
T
A
TEMPERATURE RANGE
Specified Performance
40
+85
T
T
C
T
Specifications same as grade to the left.
NOTES: (1) LSB means Least Significant Bit. (2) See Typical Performance Curves for more information. (3) f
CLK
= 2.4MHz, CS = V
CC
for 216 clock cycles out
of every 240. (4) See the Power Dissipation section for more information regarding lower sample rates.
Binary Two's Complement
3
ADS8321
ELECTROSTATIC
DISCHARGE SENSITIVITY
Electrostatic discharge can cause damage ranging from per-
formance degradation to complete device failure. Burr-
Brown Corporation recommends that all integrated circuits
be handled and stored using appropriate ESD protection
methods.
ESD damage can range from subtle performance degrada-
tion to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet
published specifications.
ABSOLUTE MAXIMUM RATINGS
(1)
V
CC
....................................................................................................... +6V
Analog Input .............................................................. 0.3V to (V
CC
+ 0.3V)
Logic Input ............................................................................... 0.3V to 6V
Case Temperature ......................................................................... +100
C
Junction Temperature .................................................................... +150
C
Storage Temperature ..................................................................... +125
C
External Reference Voltage .............................................................. +5.5V
NOTE: (1) Stresses above these ratings may permanently damage the device.
PIN
NAME
DESCRIPTION
1
V
REF
Reference Input
2
+In
Non Inverting Input
3
In
Inverting Input
4
GND
Ground
5
CS/SHDN
Chip Select when LOW, Shutdown Mode when
HIGH.
6
D
OUT
The serial output data word is comprised of 16
bits of data. In operation the data is valid on the
falling edge of DCLOCK. The second clock
pulse after the falling edge of CS enables the
serial output. After one null bit, data is valid for
the next 16 edges.
7
DCLOCK
Data Clock synchronizes the serial data transfer
and determines conversion speed.
8
+V
CC
Power Supply.
PIN ASSIGNMENTS
MAXIMUM
NO
INTEGRAL
MISSING
PACKAGE
SPECIFICATION
LINEARITY
CODES
DRAWING
TEMPERATURE
ORDERING
TRANSPORT
PRODUCT
ERROR (LSB)
ERROR (LSB)
PACKAGE
NUMBER
(1)
RANGE
NUMBER
MEDIA
ADS8321E
0.018%
14
MSOP
337
40
C to +85
C
ADS8321E/250
Tape and Reel
"
"
"
"
"
"
ADS8321E/2K5
Tape and Reel
ADS8321EB
0.012%
15
MSOP
337
40
C to +85
C
ADS8321EB/250
Tape and Reel
"
"
"
"
"
"
ADS8321EB/2K5
Tape and Reel
NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Models with a slash (/) are
available only in Tape and Reel in the quantities indicated (e.g., /2K5 indicates 2500 devices per reel). Ordering 2500 pieces of "ADS8321EB/2K5" will get a single
2500-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book.
PIN CONFIGURATION
Top View
MSOP
PACKAGE/ORDERING INFORMATION
PACKAGE/ORDERING INFORMATION
1
2
3
4
8
7
6
5
+V
CC
DCLOCK
D
OUT
CS/SHDN
V
REF
+In
In
GND
ADS8321
4
ADS8321
TYPICAL PERFORMANCE CURVES
At T
A
= +25
C, V
CC
= +5V, V
REF
= +2.5V, f
SAMPLE
= 100kHz, f
CLK
= 24 f
SAMPLE
, unless otherwise specified.
INTEGRAL LINEARITY ERROR vs CODE (+25
C)
3
2
1
0
1
2
3
4
5
6
Integral Linearity Error (LSB)
0000
H
7FF9
H
C000
H
4000
H
FFFD
H
Hex Code
FREQUENCY SPECTRUM
(8192 Point FFT, f
IN
= 10.03kHz, 0.3dB)
0
20
40
60
80
100
120
140
160
180
Amplitude (dB)
0
20
10
40
50
30
Frequency (kHz)
SUPPLY CURRENT vs TEMPERATURE
1400
1200
1000
800
600
400
200
0
Supply Current (
A)
50
0
50
100
Temperature (
C)
POWER-DOWN SUPPLY CURRENT
vs TEMPERATURE
600
500
400
300
200
100
0
Supply Current (nA)
50
25
0
25
50
75
100
Temperature (
C)
5V
QUIESCENT CURRENT vs V
CC
1.20
1.10
1.00
0.90
0.80
0.70
0.60
Quiescent Current (mA)
2.0
2.5
3.0
3.5
4.0
4.5
5.5
5.0
V
CC
(V)
DIFFERENTIAL LINEARITY ERROR vs CODE (+25
C)
3.0
2.5
2.0
1.5
1.0
0.5
0
0.5
1.0
1.5
Differential Linearity Error (LSB)
0000
H
7FFC
H
C000
H
3FFF
H
FFFD
H
Hex Code
5
ADS8321
TYPICAL PERFORMANCE CURVES
(Cont.)
At T
A
= +25
C, V
CC
= +5V, V
REF
= +2.5V, f
SAMPLE
= 100kHz, f
CLK
= 24 f
SAMPLE
, unless otherwise specified.
MAXIMUM SAMPLE RATE vs V
CC
1000
100
10
1
Sample Rate (kHz)
1
2
3
4
5
V
CC
(V)
SIGNAL-TO-NOISE AND SIGNAL-TO-(NOISE + DISTORTION)
vs INPUT FREQUENCY
90
85
80
75
70
65
SNR and SINAD (dB)
0.1
1
100
10
Input Frequency (kHz)
SNR
SINAD
SPURIOUS FREE DYNAMIC RANGE AND
TOTAL HARMONIC DISTORTION vs INPUT FREQUENCY
90
85
80
75
70
65
SNR and SINAD (dB)
0.1
1
100
10
Input Frequency (kHz)
SFDR
THD
NOISE vs REFERENCE VOLTAGE
18
16
14
12
10
8
6
4
2
0
Peak-to-Peak Noise (LSB)
0.1
1
10
Reference Voltage (V)
REFERENCE CURRENT vs SAMPLE RATE
35
30
25
20
15
10
5
0
Reference Current (
A)
0
20
40
60
80
100
120
140
Sample Rate (kHz)
2.5V
1.25V
CHANGE IN GAIN vs REFERENCE VOLTAGE
15
10
5
0
5
10
15
Change in Gain (LSB)
0
0.5
1.0
1.5
2.0
2.5
3.0
Reference Voltage (V)
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