Document Outline
- FEATURES
- APPLICATIONS
- DESCRIPTION
- ORDERING INFORMATION
- ABSOLUTE MAXIMUM RATINGS
- SPECIFICATIONS
- TIMING CHARACTERISTICS
- PIN ASSIGNMENTS
- TERMINAL FUNCTIONS
- TIMING DIAGRAMS
- TYPICAL CHARACTERISTICS
- APPLICATION INFORMATION
- MICROCONTROLLER INTERFACING
- ADS8371 to 8-Bit Microcontroller Interface
- PRINCIPLES OF OPERATION
- REFERENCE
- ANALOG INPUT
- DIGITAL INTERFACE
- Timing And Control
- Digital Inputs
- Reading Data
- RESET
- LAYOUT
ADS8371
SLAS390A - JUNE 2003 - REVISED DECEMBER 2003
16 BIT, 750 kHz, UNIPOLAR INPUT, MICRO POWER SAMPLING
ANALOG TO DIGITAL CONVERTER WITH PARALLEL INTERFACE
FEATURES
D
750-KSPS Sample Rate
D
High Linearity:
- +0.9 LSB INL Typ,
+
1.5 LSB Max
- -0.4/+0.6 LSB DNL Typ,
+
1 LSB Max
D
Onboard Reference Buffer and Conversion
Clock
D
0 V to 4.096 V Unipolar Inputs
D
Low Noise: 88 dB SNR
D
High Dynamic Range: 110 dB SFDR
D
Very Low Offset and Offset Drift
D
Low Power: 130 mW at 750 KSPS
D
Wide Buffer Supply, 2.7 V to 5.25 V
D
Flexible 8-/16-Bit Parallel Interface
D
Direct Pin Compatible With
ADS8381/ADS8383
D
48-Pin TQFP Package
APPLICATIONS
D
Medical Instruments
D
Optical Networking
D
Transducer Interface
D
High Accuracy Data Acquisition Systems
D
Magnetometers
DESCRIPTION
The ADS8371 is an 16-bit, 750 kHz A/D converter. The
device includes a 16-bit capacitor-based SAR A/D
converter with inherent sample and hold. The ADS8371
offers a full 16-bit interface or an 8-bit bus option using two
read cycles.
The ADS8371 is available in a 48-lead TQFP package and
is characterized over the industrial -40
C to 85
C
temperature range.
CDAC
_
+
Output
Latches
and
3-State
Drivers
BYTE
16-/8-Bit
Parallel DATA
Output Bus
SAR
Conversion
and
Control Logic
Comparator
Clock
+IN
-IN
REFIN
CONVST
BUSY
CS
RD
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright
2003, Texas Instruments Incorporated
ADS8371
SLAS390A - JUNE 2003 - REVISED DECEMBER 2003
www.ti.com
2
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during
storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
MODEL
MAXIMUM
INTEGRAL
LINEARITY
(LSB)
MAXIMUM
DIFFERENTIAL
LINEARITY
(LSB)
NO
MISSING
CODES
RESOLU-
TION (BIT)
PACKAGE
TYPE
PACKAGE
DESIGNATOR
TEMPER-
ATURE
RANGE
ORDERING
INFORMATION
TRANS-
PORT
MEDIA
QUANTITY
ADS8371I
2.5
-1/1.5
16
48 Pin
PFB
-40
C to
ADS8371IPFBT
Tape and
reel 250
ADS8371I
2.5
-1/1.5
16
48 Pin
TQFP
PFB
-40 C to
85
C
ADS8371IPFBR
Tape and
reel 1000
ADS8371IB
1.5
1
16
48 Pin
PFB
-40
C to
ADS8371IBPFBT
Tape and
reel 250
ADS8371IB
1.5
1
16
48 Pin
TQFP
PFB
-40 C to
85
C
ADS8371IBPFBR
Tape and
reel 1000
NOTE: For the most current specifications and package information, refer to our website at www.ti.com.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
UNIT
Voltage
+IN to AGND
-0.4 V to +VA + 0.1 V
Voltage
-IN to AGND
-0.4 V to 0.5 V
+VA to AGND
-0.3 V to 7 V
Voltage range
+VBD to BDGND
-0.3 V to 7 V
Voltage range
+VA to +VBD
-0.3 V to 2.55 V
Digital input voltage to BDGND
-0.3 V to +VBD + 0.3 V
Digital output voltage to BDGND
-0.3 V to +VBD + 0.3 V
Operating free-air temperature range, TA
-40
C to 85
C
Storage temperature range, Tstg
-65
C to 150
C
Junction temperature (TJ max)
150
C
TQFP package
Power dissipation
(TJMax - TA)/
JA
TQFP package
JA thermal impedance
86
C/W
Lead temperature, soldering
Vapor phase (60 sec)
215
C
Lead temperature, soldering
Infrared (15 sec)
220
C
(1) 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 under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
ADS8371
SLAS390A - JUNE 2003 - REVISED DECEMBER 2003
www.ti.com
3
SPECIFICATIONS
TA = -40
C to 85
C, +VA = 5 V, +VBD = 3 V or 5 V, Vref = 4.096 V, fSAMPLE = 750 kHz (unless otherwise noted)
PARAMETER
TEST
ADS8371IB
ADS8371I
UNIT
PARAMETER
TEST
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNIT
Analog Input
Full-scale input voltage (see Note 1)
+IN - -IN
0
Vref
0
Vref
V
Absolute input voltage
+IN
-0.2
Vref + 0.2
-0.2
Vref + 0.2
V
Absolute input voltage
-IN
-0.2
0.2
-0.2
0.2
V
Input capacitance
45
45
pF
Input leakage current
1
1
nA
System Performance
Resolution
16
16
Bits
No missing codes
16
16
Bits
Integral linearity (see Notes 2 and 3)
-1.5
-0.8/0.9
1.5
-2.5
2.5
LSB
Differential linearity
-1
-0.4/0.6
1
-1
1.5
LSB
Offset error
-0.75
0.25
0.75
-1
0.5
1
mV
Gain error (see Note 4)
-0.075
0.075
-0.15
0.15
%FS
Noise
60
60
V RMS
Power supply rejection ratio
At 3FFFFh
output code
75
75
dB
Sampling Dynamics
Conversion time
1.13
1.13
s
Acquisition time
0.2
0.2
s
Throughput rate
750
750
kHz
Aperture delay
4
4
ns
Aperture jitter
15
15
ps
Step response
150
150
ns
Over voltage recovery
150
150
ns
(1) Ideal input span, does not include gain or offset error.
(2) LSB means least significant bit
(3) This is endpoint INL, not best fit.
(4) Measured relative to an ideal full-scale input (+IN - -IN) of 4.096 V
ADS8371
SLAS390A - JUNE 2003 - REVISED DECEMBER 2003
www.ti.com
4
SPECIFICATIONS (CONTINUED)
TA = -40
C to 85
C, +VA = +5 V, +VBD = 3 V or 5 V, Vref = 4.096 V, fSAMPLE = 750 kHz (unless otherwise noted)
PARAMETER
TEST
ADS8371IB
ADS8371I
UNIT
PARAMETER
TEST
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNIT
Dynamic Characteristics
1 kHz
-106
-100
Total harmonic distortion (THD) (see Note 1)
10 kHz
-99
-96
dB
Total harmonic distortion (THD) (see Note 1)
50 kHz
-92
-90
dB
100 kHz
-90
-88
1 kHz
87.7
87
Signal to noise ratio (SNR) (see Note 1)
10 kHz
87.5
87
dB
Signal to noise ratio (SNR) (see Note 1)
50 kHz
87.2
87
dB
100 kHz
87
87
1 kHz
87.6
87
Signal to noise + distortion
10 kHz
87
86
dB
Signal to noise + distortion
(SINAD) (see Note 1)
50 kHz
86
85
dB
(SINAD) (see Note 1)
100 kHz
85
84
1 kHz
110
106
Spurious free dynamic range (SFDR) (see
10 kHz
100
97
dB
Spurious free dynamic range (SFDR) (see
Note 1)
50 kHz
95
92
dB
Note 1)
100 kHz
94
90
-3dB Small signal bandwidth
3
3
MHz
Voltage Reference Input
Reference voltage at REFIN, Vref
2.5
4.096
4.2
2.5
4.096
4.2
V
Reference resistance (see Note 2)
500
500
k
Reference current drain
fs = 750 kHz
1
1
mA
(1) Calculated on the first nine harmonics of the input frequency
(2) Can vary
20%
ADS8371
SLAS390A - JUNE 2003 - REVISED DECEMBER 2003
www.ti.com
5
SPECIFICATIONS (CONTINUED)
TA = -40
C to 85
C, +VA = +5 V, +VBD = 3 V or 5 V, Vref = 4.096 V, fSAMPLE = 750 kHz (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital Input/Output
Logic family
CMOS
VIH
IIH = 5
A
+VBD-1
+VBD + 0.3
Logic level
VIL
IIL = 5
A
-0.3
0.8
V
Logic level
VOH
IOH = 2 TTL loads
+VBD - 0.6
V
VOL
IOL = 2 TTL loads
0.4
Data format
Straight
Binary
Power Supply Requirements
Power supply voltage
+VBD Buffer supply
2.7
3.3
5.25
V
Power supply voltage
+VA Analog Supply
4.75
5
5.25
V
Supply current, 750-kHz sample rate (1)
26
28
mA
Power dissipation, 750-kHz sample rate (1)
130
140
mW
Temperature Range
Operating free-air
-40
85
C
(1) This includes only +VA current. +VBD current is typical 1 mA with 5 pF load capacitance on all output pins.
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