ADS-30639
Dual, 14-Bit, 6.4MHz
Sampling A/D Converter
DATEL, Inc., Mansfield, MA 02048 (USA)
Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356
E-mail: sales@datel.com
Internet: www.datel.com
PIN
FUNCTION
PIN
FUNCTION
1
INPUT "A"
28
INPUT "B"
2
RANGE
27
5V
3
+2.5V REFERENCE
26
+15V
4
ANALOG GROUND
25
+5VD
5
+5VA
24
DIGITAL GROUND
6
START CONVERT "A"
23
START CONVERT "B"
7
SELECT
22
ENABLE
8
BIT 14 (LSB)
21
BIT 1 (MSB)
9
BIT 13
20
BIT 2
10
BIT 12
19
BIT 3
11
BIT 11
18
BIT 4
12
BIT 10
17
BIT 5
13
BIT 9
16
BIT 6
14
BIT 8
15
BIT 7
FEATURES
14-bit resolution
6.4MHz sampling rate
Functionally complete
No missing codes over full military temperature range
Edge-triggered, 1.7 Watts
Small, 28-pin, ceramic DDIP
Ideal for both time and frequency-domain applications
GENERAL DESCRIPTION
The low-cost ADS-30639 is a dual 14-bit, 6.4MHz sampling
A/D converter. This device accurately samples full-scale input
signals up to Nyquist frequencies with no missing codes. The
dynamic performance of the ADS-30639 has been optimized to
achieve a signal-to-noise ratio (SNR) of 78dB and a total
harmonic distortion (THD) of 80dB. Each channel is
completely independant allowing operation with independant
analog inputs and start convert signals.
Packaged in a miniature 28-pin DDIP, the functionally complete
ADS-30639 contains two individual fast-settling sample-hold
amplifiers and subranging A/D converters, along with an
internal reference, timing/control logic, and error-correction
circuitry. Digital input and output levels are TTL. The ADS-
30639 only requires the rising edge of the start convert pulse
to operate.
Requiring only 5V and +15V supplies, the ADS-30639
dissipates 1.7 Watts. The device is offered with a bipolar
(2.0V) analog input range. Model is available for use in 55
to +125C operating temperature range. A proprietary, auto-
INPUT/OUTPUT CONNECTIONS
Figure 1. ADS-30639 Functional Block Diagram
calibrating, error-correcting circuit enables the device to
achieve specified performance over the full military
temperature range. Typical applications include medical
imaging, radar, sonar, communications and instrumentation.
+5V ANALOG SUPPLY
5
+5V DIGITAL SUPPLY 25
+15V SUPPLY
26
5V SUPPLY
27
ANALOG GROUND
4
DIGITAL GROUND
24
POWER AND GROUNDING
3
-
ST
ATE OUTPUT REGI
ST
ER
ANALOG INPUT "A"
ANALOG INPUT "B"
SELECT
START CONVERT "B"
T/H
BIT 14 (LSB)
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1 (MSB)
SUBRANGING
A/D
"B"
TIMING AND
CONTROL
LOGIC
SUBRANGING
A/D
"A"
DI
GI
TA
L
CORRECT
I
O
N L
OGI
C
T/H
ENABLE
START CONVERT "A"
1
28
6
23
22
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
ADS-30639
2
+25C
0 to +70C
55 to +125C
ANALOG INPUT
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
UNITS
Bipolar Input Voltage Range
--
2
--
--
2
--
--
2
--
Volts
Input Resistance (Vin A), (Vin B)
380
400
420
380
400
420
380
400
420
Input Capacitance
--
6
15
--
6
15
--
6
15
pF
DIGITAL INPUT
Logic Levels
Logic "1"
+2.0
--
--
+2.0
--
--
+2.0
--
--
Volts
Logic "0"
--
--
+0.8
--
--
+0.8
--
--
+0.8
Volts
Logic Loading "1"
--
--
+20
--
--
+20
--
--
+20
A
Logic Loading "0"
--
--
20
--
--
20
--
--
20
A
Start Convert Positive Pulse Width
--
50
--
--
50
--
--
50
--
ns
Input Capacitance C
IN
--
10
15
--
10
15
--
10
15
pf
STATIC PERFORMANCE
Resolution
--
14
--
--
14
--
--
14
--
Bits
Integral Nonlinearity (DC Input)
--
1
--
--
2
--
--
3
--
LSB
Differential Nonlinearity (f
in
= 10kHz)
0.90
0.5
+1
0.90
0.5
+1
0.99
0.5
+1.25
LSB
Full Scale Absolute Accuracy
--
0.1
0.3
--
0.15
0.5
--
0.5
0.8
%FSR
Bipolar Zero Error (Tech Note 2)
--
0.3
0.5
--
0.3
0.5
--
0.5
0.9
%FSR
Gain Error (Tech Note 2)
--
0.3
0.5
--
0.3
0.5
--
0.5
0.9
%FSR
No Missing Codes (f
in
= 10kHz)
14
--
--
14
--
--
14
--
--
Bits
DYNAMIC PERFORMANCE
Peak Harmonics (0.5dB)
dc to 975kHz
--
80
78
--
80
78
--
80
76
dB
975kHz to 2.4MHz
--
76
70
--
76
70
--
76
68
dB
Total Harmonic Distortion (0.5dB)
dc to 975kHz
--
80
77
--
80
77
--
80
74
dB
975kHz to 2.4MHz
--
75
69
--
75
69
--
75
67
dB
Signal-to-Noise Ratio
(w/o distortion, 0.5dB)
dc to 975kHz
76
78
--
76
78
--
75
77
--
dB
975kHz to 2.4MHz
75
77
--
75
77
--
74
76
--
dB
Signal-to-Noise Ratio
(& distortion, 0.5dB)
dc to 975kHz
74
74
--
74
74
--
73
73
--
dB
975kHz to 2.4MHz
68
72
--
68
72
--
67
72
--
dB
Noise
--
150
--
--
150
--
--
150
--
Vrms
Two-tone Intermodulation
Distortion (f
in
= 240kHz, 200kHz
f
s
= 6.4MHz, 0.5dB)
--
76
70
--
76
70
--
76
70
dB
Input Bandwidth (3dB)
Small Signal (20dB input)
--
30
--
--
30
--
--
30
--
MHz
Large Signal (0.5dB input)
--
20
--
--
20
--
--
20
--
MHz
Feedthrough Rejection (f
in
= 500kHz)
--
78
--
--
78
--
--
78
--
dB
Slew Rate
--
450
--
--
450
--
--
450
--
V/s
Aperture Delay Time
--
+1
--
--
+1
--
--
+1
--
ns
Aperture Uncertainty
--
5
--
--
5
--
--
5
--
ps rms
FUNCTIONAL SPECIFICATIONS
(T
A
= +25C, +V
DD
= +5V, V
DD
= 5V, +Vcc = +15V, 6.4MHz sampling rate, 2V input range, and a minimum 3 minute warmup
,
unless otherwise specified.)
PARAMETERS
MIN.
TYP.
MAX.
UNITS
Operating Temp. Range, Case
ADS-30639
55
--
+125
C
Thermal Impedance
jc
--
6
--
C/Watt
ca
--
23
--
C/Watt
Storage Temperature Range
65
--
+150
C
Package Type
28-pin, metal-sealed, ceramic DDIP
Weight
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
LIMITS
UNITS
+5V Supply (Pins 5, 25)
0 to +6
Volts
+15V Supply (Pin 26)
12 to 17
Volts
5V Supply (Pin 27)
0 to 6
Volts
Digital Inputs (Pins 6, 7, 22, 23 )
0.3 to +V
DD
+0.3
Volts
Analog Input (Pins 1, 28)
5
Volts
Lead Temperature (10 seconds)
+300
C
PHYSICAL/ENVIRONMENTAL
ADS-30639
3
+25C
0 to +70C
55 to +125C
DYNAMIC PERFORMANCE (Cont.)
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
UNITS
S/H Acquisition Time
( to 0.003%FSR, 5V step)
--
45
--
--
45
--
--
45
--
ns
Overvoltage Recovery Time
--
175
--
--
175
--
--
175
--
ns
A/D Conversion Rate
6.4
--
--
6.4
--
--
6.4
--
--
MHz
DIGITAL OUTPUTS
Logic Levels
Logic "1"
+2.4
--
Vcc
+2.4
--
Vcc
+2.4
--
Vcc
Volts
Logic "0"
GND
--
+0.4
GND
--
+0.4
GND
--
+0.4
Volts
Logic Loading "1"
--
--
4
--
--
4
--
--
4
mA
Logic Loading "0"
--
--
+4
--
--
+4
--
--
+4
mA
Output Coding
Two's Complement
Output Capacitance C
OUT
--
--
15
--
--
15
--
--
15
pf
Tri-State Output Leakage Current I
OZ
--
--
20
--
--
20
--
--
20
A
POWER REQUIREMENTS
Power Supply Ranges
+5V Supply
+4.9
+5.0
+5.25
+4.9
+5.0
+5.25
+4.9
+5.0
+5.25
Volts
5V Supply
4.5
5.0
5.5
4.5
5.0
5.5
4.5
5.0
5.5
Volts
+15V Supply
+13.5
+15
+16.5
+13.5
+15
+16.5
+13.5
+15
+16.5
Volts
Power Supply Currents
+5V Supply
--
220
270
--
220
270
--
220
270
mA
5V Supply
--
25
35
--
25
35
--
25
35
mA
+15V Supply
--
20
35
--
20
35
--
20
35
mA
Power Dissipation
--
1.7
1.9
--
1.7
1.9
--
1.7
1.9
Watts
Power Supply Rejection
--
--
0.05
--
--
0.05
--
--
0.05
%FSR/%V
Footnotes:
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-30639
requires careful attention to pc card layout and power
supply decoupling. The device's analog and digital ground
systems are connected to each other internally. For optimal
performance, tie all ground pins (4 and 24) directly to a
large analog ground plane beneath the package.
Bypass all power supplies to ground with 4.7 F tantalum
capacitors in parallel with 0.1 F ceramic capacitors. Locate
the bypass capacitors as close to the unit as possible.
2. The ADS-30639 achieves its specified accuracies without
the need for external calibration. It is recommended that
the +5VA and +5VD supplies should be powered up from
the same source.
3. A passive bandpass filter is used at the input of the A/D for
all production testing.
All power supplies should be on before applying a start convert pulse. All
supplies and the clock (start convert pulses) must be present during warmup
periods. The device must be continuously converting during this time.
During the 3-minute warm up period there is a slight offset and gain drift but
the dynamic specifications of the ADS-30639 are not affected.
Contact DATEL for other input voltage ranges.
A 50% duty cycle start convert pulse is used for all production testing. For
applications requiring less than an 6.4MHz sampling rate, wider start convert pulses
can be used. A 50% duty cycle is recommended for all sampling fequencies.
Effective bits is equal to:
+5 VA and 5 VD supplies are connected internally.
(SNR + Distortion) 1.76 + 20 log
Full Scale Amplitude
Actual Input Amplitude
6.02
ADS-30639
4
THERMAL REQUIREMENTS
All DATEL sampling A/D converters are fully characterized and
specified over operating temperature (case) range of
55 to +125C. All room temperature (T
A
= +25C) production
testing is performed without the use of heat sinks or forced air
cooling. Thermal impedance figures for each device are listed
in their respective specification tables.
These devices do not normally require heat sinks, however,
standard precautionary design and layout procedures should
be used to ensure devices do not overheat. The ground and
power planes beneath the package, as well as all pcb signal
runs to and from the device, should be as heavy as possible to
help conduct heat away from the package.
Electrically-insulating, thermally-conductive "pads" may be
installed underneath the package. Devices should be soldered
to boards rather than socketed, and of course, minimal air flow
over the surface can greatly help reduce the package
temperature.
In more severe ambient conditions, the package/junction
temperature of a given device can be reduced dramatically
(typically 35%) by using one of DATEL's HS Series heat sinks.
Figure 2. Timing Diagram
Min(ns)
Max(ns) Typ(ns)
Tpwh
Minimum convert pulse width high
45
--
80
Tpwl
Minimum convert pulse width low
45
--
80
Tnctdv
New conversion to internal data valid (Internal)
8
20
12
Toetdv
Output enable to data valid
20
40
30
Tseltdv
Select change to data valid
20
40
25
Tdctdv
Internal data to data valid (Internal)
8
18
12
Todtdz
Output disable to high-impedence
30
45
35
Tctdv
Conversion to data valid
16
38
24
Table 1. Output Coding
INPUT VOLT.
BIPOLAR
MSB
LSB
2V
SCALE
01 1111 1111 1111
+1.99976 +FS 1LSB
01 1000 0000 0000
+1.50000 +3/4FS
01 0000 0000 0000
+1.00000 +1/2FS
00 0000 0000 0000
0.00000 0
11 0000 0000 0000
1.00000 1/2FS
10 1000 0000 0000
1.50000 3/4FS
10 0000 0000 0001
1.99976 FS+1LSB
10 0000 0000 0000
2.00000 FS
TWO'S COMP
See Ordering Information for the assigned part number. See
page 1-183 of the DATEL Data Acquisition Components Catalog
for more information on the HS Series. Request DATEL
Application Note AN8, "Heat Sinks for DIP Data Converters", or
contact DATEL directly, for additional information.
Original Specification
V
DD
= +5V, C
L
=60pF
START
CONVERT
A & B
SELECT
Tpwh
Tctdv
Tpwl
An-3
Bn-3
An-2
An-3
Tseltdv
Tseltdv
Tctdv
An-2
Todtdz
Toetdv
Channel
B Selected
Channel
A Selected
Channel
A Selected
sample (n)
taken on
rising edge
ENABLE
DATA ON
BUS
ADS-30639
5
Figure 3. ADS-30639 Connection Diagram
ADS-30465
1
Input A
Range
2
+2.5V REF
3
+15V
26
27
5V
6
Start Con A
Start Con B
23
Select
A, B
Gnd
Enable +5VA +5VD
LSB
B13
B12
B11
B10
B9
B8
B7
B6
B5
B4
B3
B2
MSB
Input B
Male BNC
100
Male BNC
100
D1
D2
D3
D4
D5
D6
D7
EN VCC OE
Q1
Q2
Q3
Q4
Q5
Q6
Q7
74AS573
19 MSB
18
17
16
15
14
13
11
20 1.10
+5V
D1
D2
D3
D4
D5
D6
D7
EN
74AS573
Q1
Q2
Q3
Q4
Q5
Q6
Q7
OE
VCC
11
20
1.10
+5V
2
3
4
5
6
7
8
9
19
18
17
16
15
14
13 LSB
12
P1
DC25S
13
14
1
+
+
10uF
10uF
+
10uF
10uF
+
5V
+15V
7
4
24
22
5
25
+
+
10uF
10uF
+5V
+5V
11
12
13
74S86
74S86
8
9
10
3
74S86
1
2
14
+5V
6
74S86
7
5
4
+5V
+5V
14
7
8
XTAL
12.8M
MHz
2
3
1
6
5
4
PR
Q
Q
CL
C
D
+5V
74ACT74
200
+5V
+5V
200
74ACT74
PR
D
Q
C
CL
Q
13
7
11
12
14
10
9
8
Select A
Select B
+5V
28
21
20
19
18
17
16
14
13
12
11
10
9
8
15
ADS-30639
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