simultaneous sampling 12-bit A/D converters designed
for digitizing high frequency, wide dynamic range signals.
They are perfect for demanding communications applica-
tions with AC performance that includes 70.8dB SNR and
89dB spurious free dynamic range (SFDR). Ultralow jitter
of 0.08ps
RMS
allows undersampling of IF frequencies with
excellent noise performance.
DC specs include ±0.3LSB INL (typ), ±0.1LSB DNL (typ)
and no missing codes over temperature. The transition
noise is 0.3LSB
RMS
.
The digital outputs can be either full rate CMOS, double
data rate CMOS, or double data rate LVDS. A separate
output power supply allows the CMOS output swing to
range from 1.2V to 1.8V.
The ENC
+
and ENC
–
inputs may be driven differentially
or single-ended with a sine wave, PECL, LVDS, TTL, or
CMOS inputs. An optional clock duty cycle stabilizer al-
lows high performance at full speed for a wide range of
clock duty cycles.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
FEATURES
n
n
n
n
n
n
n
n
n
n
n
n
n
2-Channel Simultaneously Sampling ADC
70.8dB SNR
89dB SFDR
Low Power: 92mW/65mW/48mW Total
46mW/33mW/24mW per Channel
Single 1.8V Supply
CMOS, DDR CMOS, or DDR LVDS Outputs
Selectable Input Ranges: 1V
P-P
to 2V
P-P
750MHz Full Power Bandwidth S/H
Optional Data Output Randomizer
Optional Clock Duty Cycle Stabilizer
Shutdown and Nap Modes
Serial SPI Port for Configuration
64-Pin (9mm
×
9mm) QFN Package
APPLICATIONS
n
n
n
n
n
n
Communications
Cellular Base Stations
Software Defined Radios
Portable Medical Imaging
Multi-Channel Data Acquisition
Nondestructive Testing
TYPICAL APPLICATION
1.8V
V
DD
1.8V
OV
DD
2-Tone FFT, f
IN
= 70MHz and 69MHz
0
–10
–20
AMPLITUDE (dBFS)
CH 1
ANALOG
INPUT
S/H
12-BIT
ADC CORE
D1_11
CMOS,
DDR CMOS
OR
DDR LVDS
OUTPUTS
–30
–40
–50
–60
–70
–80
D1_0
D2_11
CH 2
ANALOG
INPUT
S/H
12-BIT
ADC CORE
OUTPUT
DRIVERS
D2_0
–90
–100
–110
–120
65MHz
CLOCK
CLOCK
CONTROL
21421012 TA01a
0
20
10
FREQUENCY (MHz)
30
21821012
TA01b
GND
OGND
21421012fa
1
LTC2142-12/
LTC2141-12/LTC2140-12
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltages (V
DD
, OV
DD
) ....................... –0.3V to 2V
Analog Input Voltage (A
IN+
, A
IN –
,
PAR/SER, SENSE) (Note 3) .......... –0.3V to (V
DD
+ 0.2V)
Digital Input Voltage (ENC
+
, ENC
–
,
CS,
SDI, SCK) (Note 4) .................................... –0.3V to 3.9V
SDO (Note 4)............................................. –0.3V to 3.9V
Digital Output Voltage ................ –0.3V to (OV
DD
+ 0.3V)
Operating Temperature Range
LTC2142C, LTC2141C, LTC2140C ............. 0°C to 70°C
LTC2142I, LTC2141I, LTC2140I ............–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
PIN CONFIGURATIONS
FULL RATE CMOS OUTPUT MODE
TOP VIEW
64 V
DD
63 SENSE
62 V
REF
61 SDO
60 OF1
59 OF2
58 D1_11
57 D1_10
56 D1_9
55 D1_8
54 D1_7
53 D1_6
52 D1_5
51 D1_4
50 D1_3
49 D1_2
DOUBLE DATA RATE CMOS OUTPUT MODE
TOP VIEW
64 V
DD
63 SENSE
62 V
REF
61 SDO
60 OF2_1
59 DNC
58 D1_10_11
57 DNC
56 D1_8_9
55 DNC
54 D1_6_7
53 DNC
52 D1_4_5
51 DNC
50 D1_2_3
49 DNC
48 D1_1
47 D1_0
46 DNC*
45 DNC*
44 DNC*
43 DNC*
42 OV
DD
41 OGND
40 CLKOUT
+
39 CLKOUT
–
38 D2_11
37 D2_10
36 D2_9
35 D2_8
34 D2_7
33 D2_6
V
DD
1
V
CM1
2
GND 3
A
IN1+
4
A
IN1–
5
GND 6
REFH 7
REFL 8
REFH 9
REFL 10
PAR/SER 11
A
IN2+
12
A
IN2–
13
GND 14
V
CM2
15
V
DD
16
65
GND
48 D1_0_1
47 DNC
46 DNC*
45 DNC*
44 DNC*
43 DNC*
42 OV
DD
41 OGND
40 CLKOUT
+
39 CLKOUT
–
38 D2_10_11
37 DNC
36 D2_8_9
35 DNC
34 D2_6_7
33 DNC
T
JMAX
= 150°C,
θ
JA
= 20°C/W
EXPOSED PAD (PIN 65) IS GND, MUST BE SOLDERED TO PCB
V
DD
17
ENC
+
18
ENC
–
19
CS
20
SCK 21
SDI 22
DNC* 23
DNC* 24
DNC* 25
DNC* 26
DNC 27
D2_0_1 28
DNC 29
D2_2_3 30
DNC 31
D2_4_5 32
UP PACKAGE
64-LEAD (9mm
×
9mm) PLASTIC QFN
V
DD
1
V
CM1
2
GND 3
A
IN1+
4
A
IN1–
5
GND 6
REFH 7
REFL 8
REFH 9
REFL 10
PAR/SER 11
A
IN2+
12
A
IN2–
13
GND 14
V
CM2
15
V
DD
16
65
GND
T
JMAX
= 150°C,
θ
JA
= 20°C/W
EXPOSED PAD (PIN 65) IS GND, MUST BE SOLDERED TO PCB
V
DD
17
ENC
+
18
ENC
–
19
CS
20
SCK 21
SDI 22
DNC* 23
DNC* 24
DNC* 25
DNC* 26
D2_0 27
D2_1 28
D2_2 29
D2_3 30
D2_4 31
D2_5 32
UP PACKAGE
64-LEAD (9mm
×
9mm) PLASTIC QFN
21421012fa
2
LTC2142-12/
LTC2141-12/LTC2140-12
PIN CONFIGURATIONS
DOUBLE DATA RATE LVDS OUTPUT MODE
TOP VIEW
64 V
DD
63 SENSE
62 V
REF
61 SDO
60 OF2_1
+
59 OF2_1
–
58 D1_10_11
+
57 D1_10_11
–
56 D1_8_9
+
55 D1_8_9
–
54 D1_6_7
+
53 D1_6_7
–
52 D1_4_5
+
51 D1_4_5
–
50 D1_2_3
+
49 D1_2_3
–
V
DD
1
V
CM1
2
GND 3
A
IN1+
4
A
IN1–
5
GND 6
REFH 7
REFL 8
REFH 9
REFL 10
PAR/SER 11
A
IN2+
12
A
IN2–
13
GND 14
V
CM2
15
V
DD
16
65
GND
48 D1_0_1
+
47 D1_0_1
–
46 DNC*
45 DNC*
44 DNC*
43 DNC*
42 OV
DD
41 OGND
40 CLKOUT
+
39 CLKOUT
–
38 D2_10_11
+
37 D2_10_11
–
36 D2_8_9
+
35 D2_8_9
–
34 D2_6_7
+
33 D2_6_7
–
T
JMAX
= 150°C,
θ
JA
= 20°C/W
EXPOSED PAD (PIN 65) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC2142CUP-12#PBF
LTC2142IUP-12#PBF
LTC2141CUP-12#PBF
LTC2141IUP-12#PBF
LTC2140CUP-12#PBF
LTC2140IUP-12#PBF
TAPE AND REEL
LTC2142CUP-12#TRPBF
LTC2142IUP-12#TRPBF
LTC2141CUP-12#TRPBF
LTC2141IUP-12#TRPBF
LTC2140CUP-12#TRPBF
LTC2140IUP-12#TRPBF
PART MARKING*
LTC2142UP-12
LTC2142UP-12
LTC2141UP-12
LTC2141UP-12
LTC2140UP-12
LTC2140UP-12
PACKAGE DESCRIPTION
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
V
DD
17
ENC
+
18
ENC
–
19
CS
20
SCK 21
SDI 22
DNC* 23
DNC* 24
DNC* 25
DNC* 26
D2_0_1
–
27
D2_0_1
+
28
D2_2_3
–
29
D2_2_3
+
30
D2_4_5
–
31
D2_4_5
+
32
UP PACKAGE
64-LEAD (9mm
×
9mm) PLASTIC QFN
21421012fa
3
LTC2142-12/
LTC2141-12/LTC2140-12
CONVERTER CHARACTERISTICS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 5)
LTC2142-12
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Gain Error
Offset Drift
Full-Scale Drift
Gain Matching
Offset Matching
Transition Noise
Internal Reference
External Reference
Differential Analog Input
(Note 7)
Internal Reference
External Reference
CONDITIONS
l
LTC2141-12
MIN
12
–0.9
–0.5
–9
–1.7
TYP
±0.3
±0.1
±1.5
±1.5
–0.3
±10
±30
±10
±0.2
±1.5
0.3
MAX
0.9
0.5
9
1.1
12
LTC2140-12
MIN
–0.9
–0.5
–9
–1.7
TYP
±0.3
±0.1
±1.5
±1.5
–0.3
±10
±30
±10
±0.2
±1.5
0.3
MAX
0.9
0.5
9
1.1
UNITS
Bits
LSB
LSB
mV
%FS
%FS
μV/°C
ppm/°C
ppm/°C
%FS
mV
LSB
RMS
MIN
12
–0.9
–0.5
–9
–1.7
TYP
±0.3
±0.1
±1.5
±1.5
–0.3
±10
±30
±10
±0.2
±1.5
0.3
MAX
0.9
0.5
9
1.1
Differential Analog Input (Note 6)
l
l
l
l
ANALOG INPUT
SYMBOL PARAMETER
V
IN
V
IN(CM)
V
SENSE
I
INCM
The
l
denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at T
A
= 25°C. (Note 5)
CONDITIONS
1.7V < V
DD
< 1.9V
Differential Analog Input (Note 8)
Per Pin, 65Msps
Per Pin, 40Msps
Per Pin, 25Msps
0 < A
IN+
, A
IN–
< V
DD
0 < PAR/SER < V
DD
0.625 < SENSE < 1.3V
Single-Ended Encode
Differential Encode
Figure 6 Test Circuit
l
l
l
l
l
l
MIN
0.7
0.625
TYP
1 to 2
V
CM
1.250
81
50
31
MAX
1.25
1.300
UNITS
V
P-P
V
V
μA
μA
μA
Analog Input Range (A
IN+
– A
IN–
)
Analog Input Common Mode (A
IN+
+ A
IN–
)/2
Analog Input Common Mode Current
External Voltage Reference Applied to SENSE External Reference Mode
I
IN1
I
IN2
I
IN3
t
AP
t
JITTER
CMRR
BW-3B
Analog Input Leakage Current (No Encode)
PAR/SER Input Leakage Current
SENSE Input Leakage Current
Sample-and-Hold Acquisition Delay Time
Sample-and-Hold Acquisition Delay Jitter
Analog Input Common Mode Rejection Ratio
Full-Power Bandwidth
–1.5
–3
–3
0
0.08
0.10
80
750
1.5
3
3
μA
μA
μA
ns
ps
RMS
ps
RMS
dB
MHz
21421012fa
4
LTC2142-12/
LTC2141-12/LTC2140-12
The
l
denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. A
IN
= –1dBFS. (Note 5)
LTC2142-12
SYMBOL
SNR
PARAMETER
Signal-to-Noise Ratio
CONDITIONS
5MHz Input
30MHz Input
70MHz Input
140MHz Input
l
DYNAMIC ACCURACY
LTC2141-12
MIN
69.2
TYP
70.5
70.5
70.4
70.2
89
89
88
84
89
89
88
84
95
95
95
95
70.4
70.4
70.3
69.9
–110
MAX
LTC2140-12
MIN
69.7
TYP
71
71
70.9
70.7
89
89
88
84
89
89
88
84
95
95
95
95
70.9
70.9
70.8
70.4
–110
MAX
UNITS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBc
MIN
69.6
TYP
70.8
70.8
70.7
70.5
89
89
88
84
89
89
88
84
95
95
95
95
70.7
70.7
70.6
70.2
–110
MAX
SFDR
Spurious Free Dynamic Range 5MHz Input
2nd Harmonic
30MHz Input
70MHz Input
140MHz Input
Spurious Free Dynamic Range 5MHz Input
3rd Harmonic
30MHz Input
70MHz Input
140MHz Input
Spurious Free Dynamic Range 5MHz Input
4th Harmonic or Higher
30MHz Input
70MHz Input
140MHz Input
l
78
80
80
l
80
80
80
l
85
85
85
S/(N+D)
Signal-to-Noise Plus
Distortion Ratio
5MHz Input
30MHz Input
70MHz Input
140MHz Input
10MHz Input
l
69.4
69.1
69.6
Crosstalk
INTERNAL REFERENCE CHARACTERISTICS
PARAMETER
V
CM
Output Voltage
V
CM
Output Temperature Drift
V
CM
Output Resistance
V
REF
Output Voltage
V
REF
Output Temperature Drift
V
REF
Output Resistance
V
REF
Line Regulation
–400μA < I
OUT
< 1mA
1.7V < V
DD
< 1.9V
–600μA < I
OUT
< 1mA
I
OUT
= 0
CONDITIONS
I
OUT
= 0
The
l
denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
1. Introduction
Electronic scales are gradually replacing traditional measuring tools like springs and balances in everyday life, such as electronic price computing scales and electronic weigh...[详细]
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