ADS-238Q Datel, Inc., ADS-238Q Datasheet - Page 2

• Manufacturer Part Number: ADS-238Q
• Description: 12-bit, 20mhz, Low Power Sampling A/D Converters
• Manufacturer: Datel, Inc.

ABSOLUTE MAXIMUM RATINGS
ADS-238Q
FUNCTIONAL SPECIFICATIONS
(T
Frequency = 20MHz, BIAS1 = 90µA, BIAS2 = 9.5µA, Duty Cycle = 50% and
Differential Input, unless otherwise specified.)
ANALOG INPUTS
DIGITAL INPUTS
REFERENCE VOLTAGES
STATIC PERFORMANCE
DYNAMIC PERFORMANCE
PARAMETERS
Supply Voltage, V
Input Voltages:
Lead Temperature (10 seconds)
Differential Input Voltage Range
Common Mode Input Voltage
Input Capacitance
Input Bandwidth, Large Signal
Logic Levels
Reference Input Voltage Range
Negative Reference Voltage
Positive Reference Voltage
Common Mode Output Voltage
Resolution
Differential Nonlinearity
Integral Nonlinearity
Common Mode rejection ratio
No Missing Codes
Offset, Mid-Scale
Gain Error
Peak Harmonics
Total Harmonics Distortion
Signal-to-Noise Ratio
Signal-to-Noise Ratio
Effective Number of Bits
A
= T
Analog Input, V
(Pin 20, 21)
V
CLK, (Pin 2)
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Input Capacitance
(V
(V
(V
(V
F
F
F
F
(w/o distortion)
F
F
(and distortion)
F
F
F
F
REF–
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
MIN
REF+
REF–
REF+
CM
= 5MHz
= 10MHz
= 5MHz
= 10MHz
= 5MHz
= 10MHz
= 5MHz
= 10MHz
= 5MHz
= 10MHz
)
, V
to T
)
)
- V
REF+,
MAX
REF–
, V
(Pin 10, 11)
)
S
IN+
S
(Pins 4-9,44)
= 3.3V, V
, V
IN–
REF–
= 1.15V, V
80% V
MIN.
±0.6
1.2
0.6
1.3
9.2
–0.5 to (+V
–0.5 to (+V
–0.5 to (+V
—
—
—
—
—
—
—
—
—
—
—
—
12
—
—
62
—
—
—
59
—
57
—
—
REF+
–0.5 to +6
S
LIMITS
+300
= 2.15V, V
TYP.
S
S
S
±1.0
1.65
1.15
2.15
1.65
±0.6
±3.0
±1.0
120
–68
–60
1.4
1.8
1.0
0.3
9.8
9.0
12
55
70
61
62
58
61
56
—
—
—
—
—
+0.5)
+0.5)
+0.5)
CM
20% V
= 1.65V, CLK
MAX.
±1.7
–61
1.9
1.7
1.8
±1
±1
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
S
UNITS
Volts
Volts
Volts
Volts
°C
UNITS
%FSR
Volts
Volts
Volts
Volts
Volts
Volts
Volts
Volts
MHz
LSB
LSB
Bits
Bits
Bits
Bits
µA
µA
dB
dB
dB
dB
dB
dB
dB
dB
dB
pF
pF
%
2
TECHNICAL NOTES
Differential Analog Input
Reference Voltage Inputs
DYNAMIC PERFORMANCE
DIGITAL OUTPUTS
POWER REQUIREMENTS
PHYSICAL/ENVIRONMENTAL
Differential Phase
Differential Gain
Aperature Uncertainty
Aperture Delay Time, t
Data Latency
A/D Conversion Rate
Logic "1"
Logic "0"
CLK to Output Delay Time, t
Supply Voltages, VS
Supply Current, I
Power Dissipation
Power Supply Rejection Ratio
Operating Temp. Range, Case
Storage Temperature Range
Package Type
Weight
The analog input is a fully differential input that can be
configured in various ways depending on whether a single-
ended or differential, AC or DC coupled input is required.
An AC coupled input is most readily implemented using a
transformer (1:1 with a center tap on the secondary
winding) as illustrated in Figures 2, Typical Connection
Diagram, and 3.1, Transformer Coupled Input. To minimize
distortion, the core of the transformer must not saturate at
full scale input voltage levels. To minimize kickback noise
from the internal sample-hold a small capacitor should be
connected across the V
Figure 3.2, DC Coupled Single Ended Input, illustrates a
conversion circuit for a DC coupled single-ended input.
Power supplies and by-pass capacitors are not shown.
The ADS-238Q is designed to accept two external
reference voltages at the V
Typical Connection Diagram. These reference voltages,
applied to V
analog input voltage range, which is equal to ±(V
V
common mode voltage, and for best performance should
be symmetrical about the midpoint of the supply voltage.
In order to minimize overall converter noise it is
recommended that the V
using a 4.7µF tantalum capacitor in parallel with a 0.01µF
ceramic capacitor. Locate the bypass capacitors as close
to the unit as possible.
REF–
). This voltage range will be symmetric about the
S
REF+
AP
(pin 11) and V
D
IN
REF
pins (pins 20 and 21).
44-pin (leaded), plastic thin quad flat package
80% V
REF
–65
2.8
pins be adequately bypassed
20
—
—
—
—
—
—
—
—
—
4
0
REF–
input pins, see Figure 2,
S
®
(pin 10), determine the
95% V
0.2
0.5
7.5
0.1
3.3
10
24
79
63
—
—
—
5
8
0.2 grams
S
+125
100
+70
0.4
3.6
12
30
—
—
—
—
—
—
—
—
REF+
Degrees
ps rms
Cycles
-
Volts
Volts
Volts
MHz
mW
mA
dB
°C
°C
ns
ns
%
®