12-Bit, 40MHz Sampling
ANALOG-TO-DIGITAL CONVERTER
FEATURES
q
LOW POWER: 390mW
q
INTERNAL REFERENCE
q
WIDEBAND TRACK-AND-HOLD: 65MHz
q
SINGLE +5V SUPPLY
DESCRIPTION
The ADS800 is a low-power, monolithic 12-bit, 40MHz Ana-
log-to-Digital (A/D) converter utilizing a small geometry CMOS
process. This complete converter includes a 12-bit quantizer,
wideband track-and-hold, reference, and three-state outputs.
It operates from a single +5V power supply and can be
configured to accept either differential or single-ended input
signals.
The ADS800 employs digital error correction to provide
excellent Nyquist differential linearity performance for de-
manding imaging applications. Its low distortion, high SNR,
and high oversampling capability give it the extra margin
needed for telecommunications, test instrumentation, and
video applications.
This high-performance A/D converter is specified over tem-
perature for AC and DC performance at a 40MHz sampling
rate. The ADS800 is available in an SO-28 package.
Pipeline
A/D
Converter
Timing
Circuitry
Error
Correction
Logic
3-State
Outputs
T/H
12-Bit
Digital
Data
CLK
+1.25V
+3.25V
MSBI
OE
IN
IN
REFT
CM
REFB
APPLICATIONS
q
IF AND BASEBAND DIGITIZATION
q
DIGITAL COMMUNICATIONS
q
ULTRASOUND IMAGING
q
GAMMA CAMERAS
q
TEST INSTRUMENTATION
q
CCD IMAGING
Copiers
Scanners
Cameras
q
VIDEO DIGITIZING
ADS800
SBAS035B FEBRUARY 1995 REVISED FEBRUARY 2005
www.ti.com
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.
Copyright 1995-2005, Texas Instruments Incorporated
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.
ADS8
00U
All trademarks are the property of their respective owners.
ADS800
2
SBAS035B
www.ti.com
ADS800U
PARAMETER
CONDITIONS
TEMP
MIN
TYP
MAX
UNITS
ELECTRICAL CHARACTERISTICS
At T
A
= +25
C, V
S
= +5V, Sampling Rate = 40MHz, and with a 50% duty cycle clock having a 2ns rise-and-fall time, unless otherwise noted.
ABSOLUTE MAXIMUM RATINGS
(1)
+V
S
....................................................................................................... +6V
Analog Input .............................................................. 0V to (+V
S
+ 300mV)
Logic Input ................................................................ 0V to (+V
S
+ 300mV)
Case Temperature ......................................................................... +100
C
Junction Temperature .................................................................... +150
C
Storage Temperature ..................................................................... +125
C
External Top Reference Voltage (REFT) .................................. +3.4V Max
External Bottom Reference Voltage (REFB) .............................. +1.1V Min
NOTE: (1) Stresses above these ratings may permanently damage the device.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper han-
dling and installation procedures can cause damage.
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 its
published specifications.
Resolution
12
Bits
Specified Temperature Range
T
AMBIENT
0
+70
C
Operating Temperature Range
T
AMBIENT
40
+85
C
ANALOG INPUT
Differential Full-Scale Input Range
Both Inputs,
+1.25
+3.25
V
180
Out-of-Phase
Common-Mode Voltage
+2.25
V
Analog Input Bandwidth (3dB)
Small-Signal
20dBFS
(1)
Input
+25
C
400
MHz
Full-Power
0dBFS Input
+25
C
65
MHz
Input Impedance
1.25 || 4
M
|| pF
DIGITAL INPUT
Logic Family
TTL/HCT Compatible CMOS
Convert Command
Start Conversion
Falling Edge
ACCURACY
(2)
f
S
= 2.5MHz
Gain Error
+25
C
0.4
1.5
%
Full
0.6
2.5
%
Gain Drift
95
ppm/
C
Power-Supply Rejection of Gain
+V
S
=
5%
+25
C
0.01
0.15
%FSR/%
Input Offset Error
Full
2.6
3.5
%
Power-Supply Rejection of Offset
+V
S
=
5%
+25
C
0.02
0.15
%FSR/%
CONVERSION CHARACTERISTICS
Sample Rate
10k
40M
Sample/s
Data Latency
6.5
Convert Cycle
DYNAMIC CHARACTERISTICS
Differential Linearity Error
f = 500kHz
t
H
= 13ns
(3)
+25
C
0.6
1.0
LSB
Full
0.8
LSB
f = 12MHz
+25
C
0.4
1.0
LSB
Full
0.5
LSB
No Missing Codes
t
H
= 13ns
(3)
+25
C
Tested
LSB
Integral Linearity Error at f = 500kHz
Full
1.9
LSB
Spurious-Free Dynamic Range (SFDR)
f = 500kHz (1dBFS input)
+25
C
65
72
dBFS
Full
60
66
dBFS
f = 12MHz (1dBFS input)
+25
C
58
61
dBFS
Full
55
61
dBFS
SPECIFIED
PACKAGE
TEMPERATURE
PACKAGE
ORDERING
TRANSPORT
PRODUCT
PACKAGE-LEAD
DESIGNATOR
RANGE
MARKING
NUMBER
MEDIA, QUANTITY
ADS800U
SO-28
DW
40
C to +85
C
ADS800U
ADS800U
Rails, 28
NOTE: (1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at
www.ti.com.
PACKAGE/ORDERING INFORMATION
(1)
NOTES: (1) dBFS refers to dB below Full-Scale. (2) Percentage accuracies are referred to the internal A/D converter Full-Scale Range of 4Vp-p. (3) To assure
DNL and no missing code performance, see timing diagram footnote 2. (4) IMD is referred to the larger of the two input signals. If referred to the peak envelope
signal (
0dB), the intermodulation products will be 7dB lower. (5) No "rollover" of bits.
ADS800
3
SBAS035B
www.ti.com
ELECTRICAL CHARACTERISTICS
(Cont.)
At T
A
= +25
C, V
S
= +5V, Sampling Rate = 40MHz, and with a 50% duty cycle clock having a 2ns rise-and-fall time, unless otherwise noted.
ADS800U
PARAMETER
CONDITIONS
TEMP
MIN
TYP
MAX
UNITS
DYNAMIC CHARACTERISTICS
(Cont.)
2-Tone Intermodulation Distortion (IMD)
(4)
f = 4.4MHz and 4.5MHz (7dBFS each tone)
+25
C
63
dBc
Full
62
dBc
Signal-to-Noise Ratio (SNR)
f = 500kHz (1dBFS input)
+25
C
61
64
dB
Full
57
63
dB
f = 12MHz (1dBFS input)
+25
C
61
62
dB
Full
56
62
dB
Signal-to-(Noise + Distortion) (SINAD)
f = 500kHz (1dBFS input)
+25
C
59
63
dB
Full
54
64
dB
f = 12MHz (1dBFS input)
+25
C
56
58
dB
Full
51
57
dB
Differential Gain Error
NTSC or PAL
+25
C
0.5
%
Differential Phase Error
NTSC or PAL
+25
C
0.1
degrees
Aperture Delay Time
+25
C
2
ns
Aperture Jitter
+25
C
7
ps rms
Over-Voltage Recovery Time
(5)
1.5x Full-Scale Input
+25
C
2
ns
OUTPUTS
Logic Family
TTL/HCT Compatible CMOS
Logic Coding
Logic Selectable
SOB or BTC
Logic Levels
Logic "LO",
Full
0
0.4
V
C
L
= 15pF max
Logic "HI",
Full
+2.5
+V
S
V
C
L
= 15pF max
3-State Enable Time
20
40
ns
3-State Disable Time
Full
2
10
ns
POWER-SUPPLY REQUIREMENTS
Supply Voltage: +V
S
Operating
Full
+4.75
+5.0
+5.25
V
Supply Current: +I
S
Operating
+25
C
78
93
mA
Operating
Full
78
97
mA
Power Consumption
Operating
+25
C
390
465
mW
Operating
Full
390
485
mW
Thermal Resistance,
JA
SO-28
75
C/W
NOTES: (1) dBFS refers to dB below Full-Scale. (2) Percentage accuracies are referred to the internal A/D converter Full-Scale Range of 4Vp-p. (3) To assure
DNL and no missing code performance, see timing diagram footnote 2. (4) IMD is referred to the larger of the two input signals. If referred to the peak envelope
signal (
0dB), the intermodulation products will be 7dB lower. (5) No "rollover" of bits.
ADS800
4
SBAS035B
www.ti.com
PIN CONFIGURATION
Top View
SO
PIN
DESIGNATOR
DESCRIPTION
1
GND
Ground
2
B1
Bit 1, Most Significant Bit
3
B2
Bit 2
4
B3
Bit 3
5
B4
Bit 4
6
B5
Bit 5
7
B6
Bit 6
8
B7
Bit 7
9
B8
Bit 8
10
B9
Bit 9
11
B10
Bit 10
12
B11
Bit 11
13
B12
Bit 12, Least Significant Bit
14
GND
Ground
15
+V
S
+5V Power Supply
16
CLK
Convert Clock Input, 50% Duty Cycle
17
+V
S
+5V Power Supply
18
OE
HI: High Impedance State. LO or Floating: Nor-
mal Operation. Internal pull-down resistors.
19
MSBI
Most Significant Bit Inversion, HI: MSB inverted
for complementary output. LO or Floating: Straight
output. Internal pull-down resistors.
20
+V
S
+5V Power Supply
21
REFB
Bottom Reference Bypass. For external bypass-
ing of internal +1.25V reference.
22
CM
Common-Mode Voltage. It is derived by (REFT +
REFB)/2.
23
REFT
Top Reference Bypass. For external bypassing
of internal +3.25V reference.
24
+V
S
+5V Power Supply
25
GND
Ground
26
IN
Input
27
IN
Complementary Input
28
GND
Ground
PIN DESCRIPTIONS
GND
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
GND
GND
IN
IN
GND
+V
S
REFT
CM
REFB
+V
S
MSBI
OE
+V
S
CLK
+V
S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
ADS800
TIMING DIAGRAM
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNITS
t
CONV
Convert Clock Period
25
100
s
ns
t
L
Clock Pulse LOW
12
12.5
ns
t
H
Clock Pulse HIGH
12
(2)
12.5
ns
t
D
Aperture Delay
2
ns
t
1
Data Hold Time, C
L
= 0pF
3.9
ns
t
2
New Data Delay Time, C
L
= 15pF max
12.5
ns
NOTES: (1) "
" indicates the portion of the waveform that will stretch out at slower sample rates.
(2) t
H
must be 13ns minimum if no missing codes is desired only for the conditions of t
CONV
28ns
and f
IN
< 2MHz.
Track
Hold
"N"
Hold
"N + 1"
Hold
"N + 2"
Hold
"N + 3"
Hold
"N + 4"
Hold
"N + 5"
Hold
"N + 6"
Track
Data Valid
N 7
Data Valid
N 6
Internal
Track-and-Hold
Convert
Clock
Output
Data
t
D
t
2
t
1
DATA LATENCY
(6.5 Clock Cycles)
t
CONV
t
L
t
H
Track
Track
Track
Track
N 3
N 5
N 4
N 2
N 1
N
Track
Track
Data Valid
N 8
(1)
Data Invalid
ADS800
5
SBAS035B
www.ti.com
TYPICAL CHARACTERISTICS
At T
A
= +25
C, V
S
= +5V, Sampling Rate = 40MHz, and with a 50% duty cycle clock having a 2ns rise-and-fall time, unless otherwise noted.
SPECTRAL PERFORMANCE
Frequency (MHz)
Amplitude (dB)
0
5
10
15
20
0
20
40
60
80
100
120
f
IN
= 500kHz
SPECTRAL PERFORMANCE
Frequency (MHz)
Amplitude (dB)
0
5
10
15
20
0
20
40
60
80
100
120
f
IN
= 1MHz
0
20
40
60
80
100
120
SPECTRAL PERFORMANCE
Frequency (MHz)
Amplitude (dB)
0
5
10
15
20
f
IN
= 5MHz
SPECTRAL PERFORMANCE
Frequency (MHz)
Amplitude (dB)
0
5
10
15
20
0
20
40
60
80
100
120
f
IN
= 12MHz
0
20
40
60
80
100
120
SPECTRAL PERFORMANCE
Frequency (MHz)
Amplitude (dB)
0
1
2
3
4
5
f
IN
= 1MHz
f
S
= 10MHz
0
20
40
60
80
100
120
2-TONE INTERMODULATION
Amplitude (dB)
0
5
10
15
20
Frequency (MHz)
f
1
= 12.5MHz
f
2
= 12.0MHz
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