ADS7841
12-Bit, 4-Channel Serial Output Sampling
ANALOG-TO-DIGITAL CONVERTER
FEATURES
q
SINGLE SUPPLY: 2.7V to 5V
q
4-CHANNEL SINGLE-ENDED OR
2-CHANNEL DIFFERENTIAL INPUT
q
UP TO 200kHz CONVERSION RATE
q
1 LSB MAX INL AND DNL
q
GUARANTEED NO MISSING CODES
q
72dB SINAD
q
SERIAL INTERFACE
q
16-PIN PDIP OR 16-LEAD SSOP PACKAGE
q
ALTERNATE SOURCE FOR MAX1247
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/ FAXLine: (800) 548-6133 (US/Canada Only) Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
DESCRIPTION
The ADS7841 is a 4-channel, 12-bit sampling analog-
to-digital converter (ADC) with a synchronous serial
interface. The resolution is programmable to either 8
or 12 bits. Typical power dissipation is 2mW at a
200kHz throughput rate and a +5V supply. The refer-
ence voltage (V
REF
) can be varied between 100mV and
V
CC
, providing a corresponding input voltage range of
0V to V
REF
. The device includes a shutdown mode
which reduces power dissipation to under 15
W. The
ADS7841 is guaranteed down to 2.7V operation.
Low power, high speed, and on-board multiplexer
make the ADS7841 ideal for battery operated systems
such as personal digital assistants, portable multi-
channel data loggers, and measurement equipment.
The serial interface also provides low-cost isolation
for remote data acquisition. The ADS7841 is available
in a 16-pin PDIP or a 16-lead SSOP package and is
guaranteed over the 40
C to +85
C temperature range.
CDAC
SAR
Comparator
Four
Channel
Multiplexer
Serial
Interface
and
Control
CH0
CH1
CH2
CH3
COM
V
REF
CS
SHDN
DIN
DOUT
MODE
BUSY
DCLK
ADS7841
ADS7841
1998 Burr-Brown Corporation
PDS-1420B
Printed in U.S.A. June, 1998
APPLICATIONS
q
DATA ACQUISITION
q
TEST AND MEASUREMENT
q
INDUSTRIAL PROCESS CONTROL
q
PERSONAL DIGITAL ASSISTANTS
q
BATTERY-POWERED SYSTEMS
2
ADS7841
SPECIFICATION: +5V
At T
A
= 40
C to +85
C, +V
CC
= +5V, V
REF
= +5V, f
SAMPLE
= 200kHz, and f
CLK
= 16 f
SAMPLE
= 3.2MHz, unless otherwise noted.
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.
ADS7841E, P
ADS7841EB, PB
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
ANALOG INPUT
Full-Scale Input Span
Positive Input - Negative Input
0
V
REF
T
T
V
Absolute Input Range
Positive Input
0.2
+V
CC
+0.2
T
T
V
Negative Input
0.2
+1.25
T
T
V
Capacitance
25
T
pF
Leakage Current
1
T
A
SYSTEM PERFORMANCE
Resolution
12
T
Bits
No Missing Codes
12
12
Bits
Integral Linearity Error
2
1
LSB
(1)
Differential Linearity Error
0.8
0.5
1
LSB
Offset Error
3
T
LSB
Offset Error Match
0.15
1.0
T
T
LSB
Gain Error
4
3
LSB
Gain Error Match
0.1
1.0
T
T
LSB
Noise
30
T
Vrms
Power Supply Rejection
70
T
dB
SAMPLING DYNAMICS
Conversion Time
12
T
Clk Cycles
Acquisition Time
3
T
Clk Cycles
Throughput Rate
200
T
kHz
Multiplexer Settling Time
500
T
ns
Aperture Delay
30
T
ns
Aperture Jitter
100
T
ps
DYNAMIC CHARACTERISTICS
Total Harmonic Distortion
(2)
V
IN
= 5Vp-p at 10kHz
78
72
80
76
dB
Signal-to-(Noise + Distortion)
V
IN
= 5Vp-p at 10kHz
68
71
70
72
dB
Spurious Free Dynamic Range
V
IN
= 5Vp-p at 10kHz
72
79
76
81
dB
Channel-to-Channel Isolation
V
IN
= 5Vp-p at 50kHz
120
T
dB
REFERENCE INPUT
Range
0.1
+V
CC
T
T
V
Resistance
DCLK Static
5
T
G
Input Current
40
100
T
T
A
f
SAMPLE
= 12.5kHz
2.5
T
A
DCLK Static
0.001
3
T
T
A
DIGITAL INPUT/OUTPUT
Logic Family
CMOS
T
Logic Levels
V
IH
| I
IH
|
+5
A
3.0
5.5
T
T
V
V
IL
| I
IL
|
+5
A
0.3
+0.8
T
T
V
V
OH
I
OH
= 250
A
3.5
T
V
V
OL
I
OL
= 250
A
0.4
T
V
Data Format
Straight Binary
T
POWER SUPPLY REQUIREMENTS
+V
CC
Specified Performance
4.75
5.25
T
T
V
Quiescent Current
550
900
T
A
f
SAMPLE
= 12.5kHz
300
T
A
Power-Down Mode
(3)
, CS = +V
CC
3
T
A
Power Dissipation
4.5
T
mW
TEMPERATURE RANGE
Specified Performance
40
+85
T
T
C
T
Same specifications as ADS7841E, P.
NOTE: (1) LSB means Least Significant Bit. With V
REF
equal to +5.0V, one LSB is 1.22mV. (2) First five harmonics of the test frequency. (3) Auto power-down mode
(PD1 = PD0 = 0) active or SHDN = GND.
3
ADS7841
SPECIFICATION: +2.7V
At T
A
= 40
C to +85
C, +V
CC
= +2.7V, V
REF
= +2.5V, f
SAMPLE
= 125kHz, and f
CLK
= 16 f
SAMPLE
= 2MHz, unless otherwise noted.
ADS7841E, P
ADS7841EB, PB
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
ANALOG INPUT
Full-Scale Input Span
Positive Input - Negative Input
0
V
REF
T
T
V
Absolute Input Range
Positive Input
0.2
+V
CC
+0.2
T
T
V
Negative Input
0.2
+0.2
T
T
V
Capacitance
25
T
pF
Leakage Current
1
T
A
SYSTEM PERFORMANCE
Resolution
12
T
Bits
No Missing Codes
12
12
Bits
Integral Linearity Error
2
1
LSB
(1)
Differential Linearity Error
0.8
0.5
1
LSB
Offset Error
3
T
LSB
Offset Error Match
0.15
1.0
T
T
LSB
Gain Error
4
3
LSB
Gain Error Match
0.1
1.0
T
T
LSB
Noise
30
T
Vrms
Power Supply Rejection
70
T
dB
SAMPLING DYNAMICS
Conversion Time
12
T
Clk Cycles
Acquisition Time
3
T
Clk Cycles
Throughput Rate
125
T
kHz
Multiplexer Settling Time
500
T
ns
Aperture Delay
30
T
ns
Aperture Jitter
100
T
ps
DYNAMIC CHARACTERISTICS
Total Harmonic Distortion
(2)
V
IN
= 2.5Vp-p at 10kHz
77
72
79
76
dB
Signal-to-(Noise + Distortion)
V
IN
= 2.5Vp-p at 10kHz
68
71
70
72
dB
Spurious Free Dynamic Range
V
IN
= 2.5Vp-p at 10kHz
72
78
76
80
dB
Channel-to-Channel Isolation
V
IN
= 2.5Vp-p at 50kHz
100
T
dB
REFERENCE INPUT
Range
0.1
+V
CC
T
T
V
Resistance
DCLK Static
5
T
G
Input Current
13
40
T
T
A
f
SAMPLE
= 12.5kHz
2.5
T
A
DCLK Static
0.001
3
T
T
A
DIGITAL INPUT/OUTPUT
Logic Family
CMOS
T
Logic Levels
V
IH
| I
IH
|
+5
A
+V
CC
0.7
5.5
T
T
V
V
IL
| I
IL
|
+5
A
0.3
+0.8
T
T
V
V
OH
I
OH
= 250
A
+V
CC
0.8
T
V
V
OL
I
OL
= 250
A
0.4
T
V
Data Format
Straight Binary
T
POWER SUPPLY REQUIREMENTS
+V
CC
Specified Performance
2.7
3.6
T
T
V
Quiescent Current
280
650
T
T
A
f
SAMPLE
= 12.5kHz
220
T
A
Power-Down Mode
(3)
, CS = +V
CC
3
T
A
Power Dissipation
1.8
T
mW
TEMPERATURE RANGE
Specified Performance
40
+85
T
T
C
T
Same specifications as ADS7841E, P.
NOTE: (1) LSB means Least Significant Bit. With V
REF
equal to +2.5V, one LSB is 610mV. (2) First five harmonics of the test frequency. (3) Auto power-down mode
(PD1 = PD0 = 0) active or SHDN = GND.
4
ADS7841
PIN CONFIGURATIONS
Top View
MINIMUM
RELATIVE
DIFFERENTIAL
SPECIFICATION
PACKAGE
ACCURACY
NONLINEARITY
TEMPERATURE
DRAWING
ORDERING
TRANSPORT
PRODUCT
(LSB)
(LSB)
RANGE
PACKAGE
NUMBER
(1)
NUMBER
(2)
MEDIA
ADS7841E
2
68
40
C to +85
C
16-Lead SSOP
322
ADS7841E
Rails
"
"
"
"
"
"
ADS7841E/2K5
Tape and Reel
ADS7841P
2
68
40
C to +85
C
16-Pin PDIP
180
ADS7841P
Rails
ADS7841EB
1
70
40
C to +85
C
16-Lead SSOP
322
ADS7841EB
Rails
"
"
"
"
"
"
ADS7841EB/2K5
Tape and Reel
ADS7841PB
1
70
40
C to +85
C
16-Pin PDIP
180
ADS7841PB
Rails
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 "ADS7841/2K5" 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.
PACKAGE/ORDERING INFORMATION
1
2
3
4
5
6
7
8
+V
CC
CH0
CH1
CH2
CH3
COM
SHDN
V
REF
DCLK
CS
DIN
BUSY
DOUT
MODE
GND
+V
CC
16
15
14
13
12
11
10
9
ADS7841
1
2
3
4
5
6
7
8
+V
CC
CH0
CH1
CH2
CH3
COM
SHDN
V
REF
DCLK
CS
DIN
BUSY
DOUT
MODE
GND
+V
CC
16
15
14
13
12
11
10
9
ADS7841
DIP
SSOP
PIN DESCRIPTIONS
PIN
NAME
DESCRIPTION
1
+V
CC
Power Supply, 2.7V to 5V.
2
CH0
Analog Input Channel 0.
3
CH1
Analog Input Channel 1.
4
CH2
Analog Input Channel 2.
5
CH3
Analog Input Channel 3.
6
COM
Ground Reference for Analog Inputs. Sets zero code voltage in single-ended mode. Connect this pin to ground or ground reference
point.
7
SHDN
Shutdown. When LOW, the device enters a very low power shutdown mode.
8
V
REF
Voltage Reference Input
9
+V
CC
Power Supply, 2.7V to 5V.
10
GND
Ground
11
MODE
Conversion Mode. When LOW, the device always performs a 12-bit conversion. When HIGH, the resolution is set by the MODE bit in
the CONTROL byte.
12
DOUT
Serial Data Output. Data is shifted on the falling edge of DCLK. This output is high impedance when CS is HIGH.
13
BUSY
Busy Output. This output is high impedance when CS is HIGH.
14
DIN
Serial Data Input. If CS is LOW, data is latched on rising edge of DCLK.
15
CS
Chip Select Input. Controls conversion timing and enables the serial input/output register.
16
DCLK
External Clock Input. This clock runs the SAR conversion process and synchronizes serial data I/O.
ABSOLUTE MAXIMUM RATINGS
(1)
+V
CC
to GND ......................................................................... 0.3V to +6V
Analog Inputs to GND ............................................ 0.3V to +V
CC
+ 0.3V
Digital Inputs to GND ........................................................... 0.3V to +6V
Power Dissipation .......................................................................... 250mW
Maximum Junction Temperature ................................................... +150
C
Operating Temperature Range ....................................... 40
C to +85
C
Storage Temperature Range ......................................... 65
C to +150
C
Lead Temperature (soldering, 10s) ............................................... +300
C
NOTE: (1) Stresses above those listed under "Absolute Maximum Ratings"
may cause permanent damage to the device. Exposure to absolute maximum
conditions for extended periods may affect device reliability.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and
installation procedures can cause damage.
ESD damage can range from subtle performance degradation 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 its published specifi-
cations.
5
ADS7841
TYPICAL PERFORMANCE CURVES:+5V
At T
A
= +25
C, +V
CC
= +5V, V
REF
= +5V, f
SAMPLE
= 200kHz, and f
CLK
= 16 f
SAMPLE
= 3.2MHz, unless otherwise noted.
0
20
40
60
80
100
120
FREQUENCY SPECTRUM
(4096 Point FFT; fIN = 1,123Hz, 0.2dB)
0
100
25
75
50
Frequency (kHz)
Amplitude (dB)
0
20
40
60
80
100
120
FREQUENCY SPECTRUM
(4096 Point FFT; fIN = 10.3kHz, 0.2dB)
0
100
25
75
50
Frequency (kHz)
Amplitude (dB)
SIGNAL-TO-NOISE RATIO AND SIGNAL-TO-
(NOISE+DISTORTION) vs INPUT FREQUENCY
10
1
100
Input Frequency (kHz)
SNR and SINAD (dB)
74
73
72
71
70
69
68
SINAD
SNR
SPURIOUS FREE DYNAMIC RANGE AND TOTAL
HARMONIC DISTORTION vs INPUT FREQUENCY
10
1
100
Input Frequency (kHz)
SFDR (dB)
THD (dB)
85
80
75
70
65
85
80
75
70
65
THD
SFDR
12.0
11.8
11.6
11.4
11.2
11.0
EFFECTIVE NUMBER OF BITS
vs INPUT FREQUENCY
10
1
100
Input Frequency (kHz)
Effective Number of Bits
CHANGE IN SIGNAL-TO-(NOISE+DISTORTION)
vs TEMPERATURE
20
40
100
Temperature (C)
Delta from +25C (dB)
0.4
0.2
0.0
0.2
0.4
0.6
0.6
0
20
40
60
80
f
IN
= 10kHz, 0.2dB
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