ADC-207 Просмотр технического описания (PDF) - DATEL Data Acquisition products
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ADC-207 Datasheet PDF : 6 Pages
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ADC-207
®
®
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
LIMITS
Power Supply Voltage (+VDD)
Digital Inputs
Analog Input
Reference Inputs
Digital Outputs
(short circuit protected to ground)
Lead Temperature (10 sec. max.)
–0.5 to +7
–0.5 to +5.5
–0.5 to (+VDD +0.5)
–0.5 to +VDD
–0.5 to +5.5
+300
UNITS
Volts
Volts
Volts
Volts
Volts
°C
PHYSICAL/ENVIRONMENTAL
PARAMETERS
MIN. TYP. MAX. UNITS
Operating Temp. Range, Case:
LC/MC Versions
MM/LM/QL Versions
Storage Temp. Range
Package Type
DIP
LCC
0
—
+70
°C
–55
—
+125
°C
–65
—
+150
°C
18-pin ceramic DIP
24-pin ceramic LCC
FUNCTIONAL SPECIFICATIONS
(Typical at +5V power, +25°C, 20MHz clock, +REFERENCE = +5V,
–REFERENCE = ground, unless noted)
ANALOG INPUT
Input Type
Input Range (dc-20MHz)
Input Impedance
Input Capacitance (Full Range)
MIN. TYP. MAX.
Single-ended, non-isolated
0
—
+5
—
1000
—
—
10
—
UNITS
Volts
Ohms
pF
DIGITAL INPUTS
Logic Levels
Logic "1"
+3.2
—
—
Volts
Logic "0"
—
—
+0.8
Volts
Logic Loading "1"
—
±1
±5 microamps
Logic Loading "0"
—
±1
±5 microamps
Sample Pulse Width
(During Sampling Portion of Clock) 12
—
—
ns
Reference Ladder Resistance
225
330
—
Ohms
PERFORMANCE
Conversion Rate
Harmonic Distortion
(8MHz 2nd Order Harmonic)
Differential Gain
Differential Phase
Aperture Delay
Aperture Jitter
No Missing Codes
LC/MC grade
LM/MM grade
Integral Linearity
Over Temperature Range
Differential Nonlinearity
Over Temperature Range
Power Supply Rejection
20
25
—
MHz
—
–40
—
dB
—
3
—
%
—
1.5
—
degrees
—
8
—
ns
—
50
—
ps
0
—
+70
°C
–55
—
+125
°C
—
±0.8
±1
LSB
±0.8
±1
LSB
—
±0.3
±0.6
LSB
—
±0.4
±0.6
LSB
—
±0.02
— %FSR/%Vs
DIGITAL OUTPUTS
Data Coding
Data Output Resolution
Logic Levels
Logic "1"
Logic "0" (at 1.6mA)
Logic Loading "1"
Logic Loading "0"
Output Data Valid Delay
(From Rising Edge)
Straight binary
7
—
—
Bits
+2.4
+4.5
—
Volts
—
—
+0.4
Volts
–4
—
—
mA
+4
—
—
mA
—
15
25
ns
POWER REQUIREMENTS
Power Supply Range (+VDD)
Power Supply Current
Power Dissipation
+3.0
+5.0
+5.5
Volts
—
+50
+70
mA
—
250
385
mW
Footnotes:
At full power input and chip selects enabled.
At 4MHz input and 20MHz clock.
For 10-step, 40 IRE NTSC ramp test.
Adjustable using reference ladder midpoint tap. See ADC-207 Operation.
TECHNICAL NOTES
1. Input Buffer Amplifier – Since the ADC-207 has a switched
capacitor type input, the input impedance of the 207 is
dependent on the clock frequency. At relatively slow
conversion rates, a general purpose type input buffer can be
used; at high conversion rates DATEL recommends either
the HA-5033 or Elantec 2003. See Figure 2 for typical
connections.
2. Reference Ladder – Adjusting the voltage at +REFERENCE
adjusts the gain of the ADC-207. Adjusting the voltage at –
REFERENCE adjusts the offset or zero of the ADC-207.
The midpoint pin is usually bypassed to ground through a
0.1µF capacitor, although it can be tied to a precision
voltage halfway between +REFERENCE and
–REFERENCE. This would improve integral linearity
beyond 7 bits.
3. Clock Pulse Width – To improve performance at Nyquist
bandwidths, the clock duty cycle can be adjusted so that the
low portion of the clock pulse is 12ns wide. The smaller
aperture allows the ADC-207 to closely resemble an ideal
sampler. See Figure 4.
4. At sampling rates less than 100kHz, there may be some
degradation in offset and differential nonlinearity.
Performance may be improved by increasing the clock duty
cycle (decreasing the time spent in the sample mode).
CAUTION
Since the ADC-207 is a CMOS device, normal precautions
against static electricity should be taken. Use ground straps,
grounded mats, etc. The Absolute Maximum Ratings of the
device MUST NOT BE EXCEEDED as irrevocable damage to
the ADC-207 will occur.
0.1µF
+15
47µF
+
20MHz
CLOCK
+5V
12
5
11
HA-5033
10 Ω
10
47µF
0.1µF
+
–15
0.1µF
+5V
4.7µF
+
0.01µF
1
CLOCK
2
DIGITAL GND
18
+VDD
B7 17 B7 (LSB)
3
–REFERENCE
B6 16 B6
4
VIN
15
B5
B5
5
14
MID
B4
B4
6
13
+REFERENCE
B3
B3
7
12
ANALOG GND
B2
B2
8
11
CS1
B1
B1 (MSB)
9
CS2
10
OF
OF
Figure 2. Typical Connections for Using the ADC-207
2
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