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Электронный компонент: MAX1425CAI

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For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
General Description
The MAX1425 10-bit, monolithic analog-to-digital con-
verter (ADC) is capable of a 20Msps sampling rate. This
device features an internal track-and-hold (T/H) amplifier
for excellent dynamic performance; at the same time, it
minimizes the number of external components. Low
input capacitance of only 8pF minimizes input drive
requirements. A wide input bandwidth (up to 150MHz)
makes this device suitable for digital RF/IF downconvert-
er applications employing undersampling techniques.
The MAX1425 employs a differential pipelined architec-
ture with a wideband T/H amplifier to maximize through-
put while limiting power consumption to only 172mW.
The MAX1425 generates an internal +2.5V reference
that supplies three additional reference voltages
(+3.25V, +2.25V, and +1.25V). These reference volt-
ages provide a differential input range of +2V to -2V.
The analog inputs are biased internally to correct the
DC level, eliminating the need for external biasing on
AC-coupled applications.
A separate +3V digital logic supply input allows for
separation of digital and analog circuitry. The output
data is in two's complement format. The MAX1425 is
available in the space-saving 28-pin SSOP package.
For a pin-compatible version at a lower data rate, refer
to the MAX1426 data sheet. For a higher data rate, refer
to the MAX1424 data sheet.
Applications
Medical Ultrasound Imaging
CCD Pixel Processing
IR Focal Plane Array
Radar
IF and Baseband Digitization
Set-Top Boxes
Features
o Differential Inputs for High Common-Mode
Noise Rejection
o Signal-to-Noise Ratio
61dB (at f
IN
= 2MHz)
59.3dB (at f
IN
= 10MHz)
o Internal +2.5V Reference
o 150MHz Input Bandwidth
o Wide 2V Input Range
o Low Power Consumption: 172mW
o Separate Digital Supply Input for 3V Logic
Compatibility
o Single +5V Supply Operation Possible
MAX1425
10-Bit, 20Msps ADC
________________________________________________________________ Maxim Integrated Products
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
D0
D1
D2
D3
D4
DGND
D9
DV
DD
DGND
DV
DD
D5
D6
D7
D8
OE/PD
CLK
CMLN
CMLP
INN
INP
AV
DD
AGND
CML
REFN
REFIN
REFP
AV
DD
AGND
SSOP
TOP VIEW
MAX1425
CLK
INP
INTERFACE
PIPELINE ADC
REF SYSTEM +
BIAS
OUTPUT
DRIVERS
REF
REFIN REFP
CML REFN
OE/PD
AV
DD
AGND
DV
DD
DGND
D9D0
INN
T/H
MAX1425
Functional Diagram
19-1597; Rev 0; 1/00
Pin Configuration
Ordering Information
PART
MAX1425CAI
MAX1425EAI
-40C to +85C
0C to +70C
TEMP. RANGE
PIN-PACKAGE
28 SSOP
28 SSOP
MAX1425
10-Bit, 20Msps ADC
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
AVDD
= V
CMLP
= +5V, V
DVDD
= +3.3V, V
CMLN
= V
AGND
= V
DGND
= 0, internal reference, digital output load = 35pF, f
CLK
= 20MHz
(50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
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 in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
AV
DD
to AGND ........................................................ -0.3V to +6V
DV
DD
to DGND ....................................................... -0.3V to +6V
AV
DD
to DGND ........................................................ -0.3V to +6V
DGND to AGND ................................................................. 0.3V
REFP, REFIN, REFN, CMLN, CMLP,
CML, INP, INN ....................(V
AGND
- 0.3V) to (V
AVDD
+ 0.3V)
CLK, OE/PD, D0D9 ...............(V
DGND
- 0.3V) to (V
DVDD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70C)
28-Pin SSOP (derated 9.5mW/C above +70C) .........762mW
Operating Temperature Ranges
MAX1425CAI ..................................................... 0C to +70C
MAX1425EAI................................................... -40C to +85C
Junction Temperature ..................................................... +150C
Storage Temperature Range ............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
SINAD
dB
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Gain Error
GE
-10
5
10
Midscale Offset
MSO
-3
1.0
3
No Missing Codes
Integral Nonlinearity
INL
-1.5
0.3
1.5
LSB
-5
2
5
-5
3 5
Power-Supply Rejection Ratio
PSRR
-5
2
5
mV/V
Resolution
RES
10
Bits
Differential Nonlinearity
DNL
-1
1
LSB
Signal-to-Noise Ratio
SNR
60
61
dB
Spurious-Free Dynamic Range
SFDR
70
72
dB
Total Harmonic Distortion
(first five harmonics)
THD
-70
-67
dB
Signal-to-Noise and Distortion
59
61
CONDITIONS
f = 2MHz
Internal reference (Note 1)
(Note 1)
Guaranteed monotonic
External reference (REFIN) (Note 2)
External reference (REFP, CML, REFN)
(Note 3)
(Note 4)
f = 2MHz
f = 2MHz
f = 2MHz
%FSR
%FSR
f = 10MHz
56
59
f = 10MHz
64
69
f = 10MHz
-69
-64
f = 10MHz
55
59
ENOB
Bits
Effective Number of Bits
9.3
9.7
f = 2MHz
f = 10MHz
8.8
9.5
IMD
dBc
Intermodulation Distortion
-70
f1 = 10.17MHz, f2 = 10.19MHz
(-7dB FS, each tone) (Note 5)
ACCURACY
DYNAMIC PERFORMANCE (V
INP
- V
INN
= +2V to -2V)
MAX1425
10-Bit, 20Msps ADC
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
CMLP
= +5V, V
DVDD
= +3.3V, V
CMLN
= V
AGND
= V
DGND
= 0, internal reference, digital output load = 35pF, f
CLK
= 20MHz
(50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
Common-Mode Reference
Voltage
V
CML
2.25
V
(Note 1)
Differential Reference
Temperature Coefficient
50
ppm/C
Positive Reference Voltage
V
REFP
3.25
V
Common-Mode Reference
Voltage
V
CML
2.25
V
Negative Reference Input
Voltage
V
REFN
1.25
V
Differential Reference
1.9
2.0
2.1
V
Positive Reference
V
REFP
3.25
V
V
REFP
- V
REFN
, T
A
= +25C
(Note 1)
Input Resistance
R
IN
6.5
k
Input Capacitance
C
IN
10
pF
Differential Reference
2.0
V
Input Current
I
IN
-325
325
A
Input Capacitance
C
IN
15
pF
REFP Input Range
3.25
10%
V
CML Input Range
2.25
10%
V
REFN Input Range
1.25
10%
V
REFIN (Note 8)
REFIN
V
REFP
- V
REFN
REFP, CML, REFN
REFP, CML, REFN
Input Resistance
R
IN
3.5
k
Input Capacitance
C
IN
8
pF
Input Common-Mode Voltage
Range
V
CMVR
2.25
10%
V
Differential Input Range
DR
2
V
Small-Signal Bandwidth
SSBW
400
MHz
Large-Signal Bandwidth
LSBW
150
MHz
Either input to ground
Either input to ground
CML (Note 6)
V
INP
- V
INN
(Note 7)
(Note 7)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
Negative Reference
V
REFN
1.25
V
(Note 1)
Differential Reference
1.8
2
2.2
V
V
REFP
- V
REFN
, T
A
= +25C
Differential Reference
Temperature Coefficient
150
ppm/C
ANALOG INPUT (INP, INN, CML)
REFERENCE (V
REFIN
= 0; REFP, REFN, CML applied externally)
REFERENCE OUTPUTS (REFP, CML, REFN; external +2.5V reference)
REFERENCE OUTPUTS (REFP, CML, REFN; internal +2.5V reference)
MAX1425
10-Bit, 20Msps ADC
4
_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
CMLP
= +5V, V
DVDD
= +3.3V, V
CMLN
= V
AGND
= V
DGND
= 0, internal reference, digital output load = 35pF, f
CLK
= 20MHz
(50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
I
OE/PD
OE/PD = DV
DD
V
DVDD
= 5.25V, OE/PD = DV
DD
I
OL
= 200A, V
DVDD
= 2.7V
I
OH
= -200A, V
DVDD
= 2.7V
V
DVDD
= 5.25V
V
DVDD
< 4.75V
V
DVDD
> 4.75V
OE/PD = DV
DD
V
DVDD
= 5.0V
REFIN = AGND
OE/PD = DV
DD
V
DVDD
< 4.75V
V
DVDD
= 3.3V
V
DVDD
> 4.75V
CONDITIONS
pF
10
Three-State Capacitance
A
-10
10
Three-State Leakage
V
0.5
VOL
Output Logic Low
V
V
DVDD
V
DVDD
- 0.5
VOH
Output Logic High
pF
10
Input Capacitance
A
-20
20
A
-10
10
Input Current Leakage
0.3
V
DVDD
V
0.8
V
IL
Input Logic Low
0.7
V
DVDD
V
2.4
V
IH
Input Logic High
mW
172
220
PD
Power Dissipation
A
90
150
Digital Shutdown Current
8.5
14
mA
26
35
Analog Supply Current with
Internal Reference in Shutdown
nA
0.6
1
Analog Shutdown Current
mA
5.3
9
I
DVDD
Digital Supply Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
Figure 4
Figure 4
ps
7
t
AJ
Aperture Jitter
ns
5
t
AD
Aperture Delay
cycles
5.5
Pipeline Delay (Latency)
ns
20
25
30
t
CL
Clock Low
ns
20
25
30
t
CH
Clock High
MHz
20
f
CLK
Clock Frequency
MHz
0.1
20
CONV
Conversion Rate
V
2.7
3.3
5.5
V
DVDD
Digital Supply Voltage
V
4.75
5.00
5.25
V
AVDD
Analog Supply Voltage
mA
31
38
I
AVDD
Analog Supply Current
I
CLK
ns
10
20
t
AJ
Bus Disable
ns
10
20
t
AD
Bus Enable
ns
5
20
25
t
OD
Data Output Delay
POWER SUPPLY
DIGITAL INPUTS (CLK, OE/PD)
DIGITAL OUTPUTS (D0D9)
TIMING CHARACTERISTICS
MAX1425
10-Bit, 20Msps ADC
_______________________________________________________________________________________
5
ELECTRICAL CHARACTERISTICS (continued)
Note 1:
Internal reference, REFIN bypassed to AGND with a 0.1F capacitor.
Note 2:
External +2.5V reference applied to REFIN.
Note 3:
Internal reference disabled. V
REFIN
= 0, V
REFP
= 3.25V, V
CML
= 2.25V, and V
REFN
= 1.25V.
Note 4:
Measured as the ratio of the change in midscale offset voltage for a 5% change in V
AVDD
using the internal reference.
Note 5:
IMD is measured with respect to either of the fundamental tones.
Note 6:
Specifies the common-mode range of the differential input signal supplied to the MAX1425.
Note 7:
Defined as the input frequency at which the fundamental component of the output spectrum is attenuated by 3dB.
Note 8:
V
REFIN
is internally biased to +2.5V through a 5k
resistor.
Typical Operating Characteristics
(V
AVDD
= V
CMLP
= +5V, V
DVDD
= +3.3V, V
CMLN
= V
AGND
= 0, internal reference, digital output load = 35pF, f
CLK
= 20Msps (50%
duty cycle), for dynamic performance 0dB is full scale, T
A
= +25C, unless otherwise noted.)
-1.2
-0.6
-0.8
-1.0
-0.4
-0.2
0
0.2
0.4
0.6
0.8
0
400
200
600
800
1000
INTEGRAL NONLINEARITY vs. CODE
MAX1425-01
CODE
INL (LSB)
f
INP
= 2MHz
-0.6
-0.2
-0.4
0
0.2
0.4
0.6
0
400
200
600
800
1000
DIFFERENTIAL NONLINEARITY vs. CODE
MAX1425-02
CODE
DNL (LSB)
f
INP
= 2MHz
-8.0
-6.0
-7.0
-5.0
-4.0
-3.0
-2.0
-1.0
0
0.01
1
0.1
10
100
1000 10,000
ANALOG INPUT BANDWIDTH
(FULL POWER)
MAX1425-03
BANDWIDTH (MHz)
AMPLITUDE (dB)
-140
-100
-120
-60
-80
-20
-40
0
0
4
2
6
8
1
5
3
7
9
10
INTERMODULATION DISTORTION
vs. FREQUENCY
MAX1425-04
FREQUENCY (MHz)
MAGNITUDE (dB)
f
CLK
= 20MHz
f1 = 5.01MHz
f2 = 5.03MHz
f
CLK
= 20MHz
f1 = 5.01MHz
f2 = 5.03MHz
0
20
40
60
SIGNAL-TO-NOISE PLUS DISTORTION
vs. POWER (f
IN
= 2.003MHz)
MAX1425-05
INPUT (dB)
SINAD (dB)
-60
-30
-45
-15
0
0
20
40
60
SIGNAL-TO-NOISE RATIO PLUS DISTORTION
vs. POWER (f
IN
= 5.009MHz)
MAX1425-06
INPUT (dB)
SNDR (dB)
-60
-30
-45
-15
0