LINER LTC1748 12-bit,170msps/ 135msps adc Datasheet

LTC2220/LTC2221
12-Bit,170Msps/
135Msps ADCs
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FEATURES
DESCRIPTIO
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The LTC®2220 and LTC2221 are 170Msps/135Msps, sampling 12-bit A/D converters designed for digitizing high
frequency, wide dynamic range signals. The LTC2220/
LTC2221 are perfect for demanding communications
applications with AC performance that includes 67.5dB
SNR and 80dB spurious free dynamic range for signals
up to 170MHz. Ultralow jitter of 0.15psRMS allows
undersampling of IF frequencies with excellent noise
performance.
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Sample Rate: 170Msps/135Msps
67.5dB SNR up to 140MHz Input
80dB SFDR up to 170MHz Input
775MHz Full Power Bandwidth S/H
Single 3.3V Supply
Low Power Dissipation: 890mW/660mW
LVDS, CMOS, or Demultiplexed CMOS Outputs
Selectable Input Ranges: ±0.5V or ±1V
No Missing Codes
Optional Clock Duty Cycle Stabilizer
Shutdown and Nap Modes
Data Ready Output Clock
Pin Compatible Family
185Msps: LTC2220-1 (12-Bit)
170Msps: LTC2220 (12-Bit), LTC2230 (10-Bit)
135Msps: LTC2221 (12-Bit), LTC2231 (10-Bit)
64-Pin 9mm × 9mm QFN Package
DC specs include ±0.4LSB INL (typ), ±0.3LSB DNL (typ)
and no missing codes over temperature. The transition
noise is a low 0.5LSBRMS.
The digital outputs can be either differential LVDS, or
single-ended CMOS. There are three format options for
the CMOS outputs: a single bus running at the full data rate
or two demultiplexed buses running at half data rate with
either interleaved or simultaneous update. A separate
output power supply allows the CMOS output swing to
range from 0.5V to 3.6V.
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APPLICATIO S
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Wireless and Wired Broadband Communication
Cable Head-End Systems
Power Amplifier Linearization
Communications Test Equipment
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 allows high
performance at full speed for a wide range of clock duty
cycles.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATIO
SFDR vs Input Frequency
3.3V
VDD
REFH
REFL
100
0.5V
TO 3.6V
FLEXIBLE
REFERENCE
90
OVDD
INPUT
S/H
–
12-BIT
PIPELINED
ADC CORE
CORRECTION
LOGIC
D11
•
•
•
D0
OUTPUT
DRIVERS
CMOS
OR
LVDS
OGND
CLOCK/DUTY
CYCLE
CONTROL
70
2nd OR 3rd
60
50
22201 TA01
ENCODE
INPUT
SFDR (dBFS)
+
ANALOG
INPUT
4th OR HIGHER
80
40
0
100
200
300
400
500
600
INPUT FREQUENCY (MHz) 22201 TA01b
22201fa
1
LTC2220/LTC2221
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ABSOLUTE
AXI U RATI GS
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W
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PACKAGE/ORDER I FOR ATIO
OVDD = VDD (Notes 1, 2)
TOP VIEW
64 GND
63 VDD
62 VDD
61 GND
60 VCM
59 SENSE
58 MODE
57 LVDS
56 OF +/OFA
55 OF –/DA11
54 D11+/DA10
53 D11–/DA9
52 D10+/DA8
51 D10 –/DA7
50 OGND
49 OVDD
Supply Voltage (VDD) ................................................. 4V
Digital Output Ground Voltage (OGND) ....... –0.3V to 1V
Analog Input Voltage (Note 3) ..... –0.3V to (VDD + 0.3V)
Digital Input Voltage .................... –0.3V to (VDD + 0.3V)
Digital Output Voltage ............... –0.3V to (OVDD + 0.3V)
Power Dissipation ............................................ 1500mW
Operating Temperature Range
LTC2220C, LTC2221C ............................. 0°C to 70°C
LTC2220I, LTC2221I ...........................–40°C to 85°C
Storage Temperature Range ..................–65°C to 125°C
AIN+ 1
AIN+ 2
AIN– 3
AIN– 4
REFHA 5
REFHA 6
REFLB 7
REFLB 8
REFHB 9
REFHB 10
REFLA 11
REFLA 12
VDD 13
VDD 14
VDD 15
GND 16
48 D9+/DA6
47 D9–/DA5
46 D8+/DA4
45 D8–/DA3
44 D7 +/DA2
43 D7 –/DA1
42 OVDD
41 OGND
40 D6+/DA0
39 D6–/CLOCKOUTA
38 D5+/CLOCKOUTB
37 D5–/OFB
36 CLOCKOUT +/DB11
35 CLOCKOUT –/DB10
34 OVDD
33 OGND
ENC + 17
ENC – 18
SHDN 19
OE 20
DO–/DB0 21
+
DO /DB1 22
D1–/DB2 23
D1+/DB3 24
OGND 25
OVDD 26
D2–/DB4 27
+
D2 /DB5 28
D3–/DB6 29
D3+/DB7 30
D4–/DB8 31
D4+/DB9 32
65
UP PACKAGE
64-LEAD (9mm × 9mm) PLASTIC QFN
TJMAX = 125°C, θJA = 20°C/W
EXPOSED PAD (PIN 65) IS GND, MUST BE SOLDERED TO PCB
UP PART MARKING*
ORDER PART NUMBER
LTC2220CUP
LTC2220IUP
LTC2221CUP
LTC2221IUP
LTC2220UP
LTC2220UP
LTC2221UP
LTC2221UP
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The temperature grade is identified by a label on the shipping container.
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CO VERTER CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 4)
PARAMETER
CONDITIONS
MIN
LTC2220
TYP
MAX
MIN
LTC2221
TYP
MAX
●
12
Differential Analog Input (Note 5)
●
–1.5
±0.4
1.5
–1
±0.4
1
Differential Linearity Error
Differential Analog Input
●
–1
±0.3
1
–1
±0.2
1
Integral Linearity Error
Single-Ended Analog Input (Note 5)
Resolution (No Missing Codes)
Integral Linearity Error
12
±1
Bits
±1
±0.3
LSB
LSB
LSB
±0.2
Differential Linearity Error
Single-Ended Analog Input
Offset Error
(Note 6)
●
–35
±3
35
–35
±3
35
Gain Error
External Reference
●
–2.5
±0.5
2.5
–2.5
±0.5
2.5
Offset Drift
UNITS
LSB
mV
%FS
±10
±10
µV/C
Full-Scale Drift
Internal Reference
External Reference
±30
±15
±30
±15
ppm/C
ppm/C
Transition Noise
SENSE = 1V
0.5
0.5
LSBRMS
22201fa
2
LTC2220/LTC2221
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A ALOG I PUT
The ● denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
VIN
Analog Input Range (AIN+ – AIN–)
3.1V < VDD < 3.5V (Note 7)
●
VIN, CM
Analog Input Common Mode (AIN+
Differential Input (Note 7)
Single Ended Input (Note 7)
●
●
1
0.5
IIN
Analog Input Leakage Current
0 < AIN+, AIN– < VDD
●
–1
ISENSE
SENSE Input Leakage
0V < SENSE < 1V
●
–1
IMODE
MODE Pin Pull-Down Current to GND
10
µA
ILVDS
LVDS Pin Pull-Down Current to GND
10
µA
tAP
Sample and Hold Acquisition Delay Time
0
ns
tJITTER
Sample and Hold Acquisition Delay Time Jitter
0.15
CMRR
Analog Input Common Mode Rejection Ratio
80
dB
775
MHz
+ AIN–)/2
Full Power Bandwidth
MIN
TYP
MAX
UNITS
±0.5 to ±1
Figure 8 Test Circuit
1.6
1.6
V
1.9
2.1
V
V
1
µA
µA
1
psRMS
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DY A IC ACCURACY
The ● denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. AIN = –1dBFS. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
SNR
Signal-to-Noise Ratio
(Note 10)
5MHz Input (1V Range)
5MHz Input (2V Range)
70MHz Input (1V Range)
70MHz Input (2V Range)
SFDR
SFDR
S/(N+D)
MIN
62.7
67.7
●
65.8
62.7
67.6
65.8
LTC2221
TYP
MAX
UNITS
62.8
67.8
dB
dB
62.8
67.8
dB
dB
62.5
67.5
dB
dB
250MHz Input (1V Range)
250MHz Input (2V Range)
61.8
66.1
61.8
66.1
dB
dB
84
84
84
84
dB
dB
84
84
dB
dB
●
70
84
84
70
140MHz Input (1V Range)
140MHz Input (2V Range)
84
84
84
84
dB
dB
250MHz Input (1V Range)
250MHz Input (2V Range)
74
73
77
77
dB
dB
90
90
90
90
dB
dB
90
90
dB
dB
Spurious Free Dynamic Range 5MHz Input (1V Range)
4th Harmonic or Higher
5MHz Input (2V Range)
(Note 11)
70MHz Input (1V Range)
70MHz Input (2V Range)
Intermodulation Distortion
MAX
62.4
67.5
●
75
90
90
75
140MHz Input (1V Range)
140MHz Input (2V Range)
87
87
90
90
dB
dB
250MHz Input (1V Range)
250MHz Input (2V Range)
85
85
90
90
dB
dB
62.7
67.5
62.8
67.6
dB
dB
62.8
67.4
dB
dB
81
dBc
5MHz Input (1V Range)
5MHz Input (2V Range)
70MHz Input (1V Range)
70MHz Input (2V Range)
IMD
LTC2220
TYP
140MHz Input (1V Range)
140MHz Input (2V Range)
Spurious Free Dynamic Range 5MHz Input (1V Range)
2nd or 3rd Harmonic
5MHz Input (2V Range)
(Note 11)
70MHz Input (1V Range)
70MHz Input (2V Range)
Signal-to-Noise Plus
Distortion Ratio (Note 12)
MIN
fIN1 = 138MHz, fIN2 = 140MHz
●
65
62.7
67.3
81
65
22201fa
3
LTC2220/LTC2221
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I TER AL REFERE CE CHARACTERISTICS
(Note 4)
PARAMETER
CONDITIONS
MIN
TYP
MAX
VCM Output Voltage
IOUT = 0
1.570
1.600
1.630
±25
VCM Output Tempco
UNITS
V
ppm/°C
VCM Line Regulation
3.1V < VDD < 3.5V
3
mV/V
VCM Output Resistance
–1mA < IOUT < 1mA
4
Ω
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DIGITAL I PUTS A D DIGITAL OUTPUTS
The ● denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2.5
V
V
ENCODE INPUTS (ENC +, ENC –)
VID
Differential Input Voltage
VICM
Common Mode Input Voltage
RIN
Input Resistance
CIN
Input Capacitance
●
Internally Set
Externally Set (Note 7)
●
0.2
1.1
(Note 7)
V
1.6
1.6
6
kΩ
3
pF
LOGIC INPUTS (OE, SHDN)
VIH
High Level Input Voltage
VDD = 3.3V
●
VIL
Low Level Input Voltage
VDD = 3.3V
●
IIN
Input Current
VIN = 0V to VDD
●
CIN
Input Capacitance
(Note 7)
2
V
–10
0.8
V
10
µA
3
pF
LOGIC OUTPUTS (CMOS MODE)
OVDD = 3.3V
COZ
Hi-Z Output Capacitance
OE = High (Note 7)
3
pF
ISOURCE
Output Source Current
VOUT = 0V
50
mA
ISINK
Output Sink Current
VOUT = 3.3V
50
mA
VOH
High Level Output Voltage
IO = –10µA
IO = –200µA
●
IO = 10µA
IO = 1.6mA
●
VOL
Low Level Output Voltage
3.1
3.295
3.29
0.005
0.09
V
V
0.4
V
V
OVDD = 2.5V
VOH
High Level Output Voltage
IO = –200µA
2.49
V
VOL
Low Level Output Voltage
IO = 1.6mA
0.09
V
VOH
High Level Output Voltage
IO = –200µA
1.79
V
VOL
Low Level Output Voltage
IO = 1.6mA
0.09
V
OVDD = 1.8V
LOGIC OUTPUTS (LVDS MODE)
VOD
Differential Output Voltage
100Ω Differential Load
●
247
350
454
VOS
Output Common Mode Voltage
100Ω Differential Load
●
1.125
1.250
1.375
mV
V
22201fa
4
LTC2220/LTC2221
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POWER REQUIRE E TS
The ● denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 9)
MIN
LTC2220
TYP
MAX
PARAMETER
CONDITIONS
VDD
Analog Supply Voltage
(Note 8)
PSHDN
Shutdown Power
SHDN = High, OE = High, No CLK
2
2
mW
PNAP
Nap Mode Power
SHDN = High, OE = Low, No CLK
35
35
mW
●
3.1
3.3
3.5
MIN
LTC2221
TYP
MAX
SYMBOL
3.1
3.3
UNITS
3.5
V
LVDS OUTPUT MODE
(Note 8)
●
OVDD
Output Supply Voltage
3
3.3
3.6
264
288
3
3.3
3.6
V
IVDD
Analog Supply Current
●
196
212
mA
IOVDD
Output Supply Current
●
55
70
55
70
mA
PDISS
Power Dissipation
●
1050
1182
828
931
mW
CMOS OUTPUT MODE
OVDD
Output Supply Voltage
IVDD
Analog Supply Current
PDISS
Power Dissipation
(Note 8)
●
0.5
●
3.3
3.6
264
288
0.5
890
3.3
3.6
V
196
212
mA
660
mW
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TI I G CHARACTERISTICS
The ● denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
MIN
fS
Sampling Frequency
(Note 8)
●
1
tL
ENC Low Time (Note 7)
Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
●
●
2.8
2
tH
ENC High Time (Note 7)
Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
●
●
2.8
2
tAP
Sample-and-Hold Aperture Delay
tOE
Output Enable Delay
(Note 7)
●
LTC2220
TYP
MAX
MIN
LTC2221
TYP
MAX
UNITS
135
MHz
170
1
2.94
2.94
500
500
3.5
2
3.7
3.7
500
500
ns
ns
2.94
2.94
500
500
3.5
2
3.7
3.7
500
500
ns
ns
0
0
5
10
ns
5
10
ns
LVDS OUTPUT MODE
tD
ENC to DATA Delay
(Note 7)
●
1.3
2.2
3.5
1.3
2.2
3.5
ns
tC
ENC to CLOCKOUT Delay
(Note 7)
●
1.3
2.2
3.5
1.3
2.2
3.5
ns
DATA to CLOCKOUT Skew
(tC - tD) (Note 7)
●
–0.6
0
0.6
–0.6
0
0.6
ns
Rise Time
0.5
0.5
ns
Fall Time
0.5
0.5
ns
5
5
Pipeline Latency
Cycles
CMOS OUTPUT MODE
tD
ENC to DATA Delay
(Note 7)
●
1.3
2.1
3.5
1.3
2.1
3.5
ns
tC
ENC to CLOCKOUT Delay
(Note 7)
●
1.3
2.1
3.5
1.3
2.1
3.5
ns
DATA to CLOCKOUT Skew
(tC - tD) (Note 7)
●
–0.6
0
0.6
–0.6
0
0.6
Pipeline Latency Full Rate CMOS
Demuxed Interleaved
Demuxed Simultaneous
ns
5
5
Cycles
5
5
Cycles
5 and 6
5 and 6
Cycles
22201fa
5
LTC2220/LTC2221
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All voltage values are with respect to ground with GND and OGND
wired together (unless otherwise noted).
Note 3: When these pin voltages are taken below GND or above VDD, they will
be clamped by internal diodes. This product can handle input currents of
greater than 100mA below GND or above VDD without latchup.
Note 4: VDD = 3.3V, fSAMPLE = 170MHz (LTC2220) or 135MHz (LTC2221),
LVDS outputs, differential ENC+/ENC– = 2VP-P sine wave, input range =
2VP-P with differential drive, unless otherwise noted.
Note 5: Integral nonlinearity is defined as the deviation of a code from a “best
straight line” fit to the transfer curve. The deviation is measured from the
center of the quantization band.
Note 6: Offset error is the offset voltage measured from –0.5 LSB when the
output code flickers between 0000 0000 0000 and 1111 1111 1111 in 2’s
complement output mode.
Note 7: Guaranteed by design, not subject to test.
Note 8: Recommended operating conditions.
Note 9: VDD = 3.3V, fSAMPLE = 170MHz (LTC2220) or 135MHz (LTC2221),
differential ENC+/ENC– = 2VP-P sine wave, input range = 1VP-P with differential
drive, output CLOAD = 5pF.
Note 10: SNR minimum and typical values are for LVDS mode. Typical values
for CMOS mode are typically 0.3dB lower.
Note 11: SFDR minimum values are for LVDS mode. Typical values are for
both LVDS and CMOS modes.
Note 12: SINAD minimum and typical values are for LVDS mode. Typical
values for CMOS mode are typically 0.3dB lower.
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TYPICAL PERFOR A CE CHARACTERISTICS
1.0
1.0
0.8
0.8
0.6
0.6
0.4
0.4
0
– 0.2
0
– 0.2
– 0.4
– 0.6
– 0.6
– 0.8
– 0.8
– 1.0
– 1.0
3072
2048
OUTPUT CODE
4096
24266
20000
1024
3072
2048
OUTPUT CODE
68
68
67
67
62
61
61
600
2220 G04
80
70
60
50
60
400
500
INPUT FREQUENCY (MHz)
2060
90
64
62
300
2059
100
65
63
200
2058
CODE
LTC2220: SFDR (HD2 and HD3)
vs Input Frequency, –1dB, 2V
Range, LVDS Mode
66
63
60
2057
2220 G03
SFDR (dBFS)
69
SNR (dBFS)
SNR (dBFS)
70
69
100
2056
4096
2220 G02
70
64
140
–0
LTC2220: SNR vs Input
Frequency, –1dB, 1V Range,
LVDS Mode
65
12866
229
0
LTC2220: SNR vs Input
Frequency, –1dB, 2V Range,
LVDS Mode
0
60000
40000
2220 G01
66
93571
80000
0.2
– 0.4
1024
100000
COUNT
0.2
0
LTC2220: Shorted Input Noise
Histogram
LTC2220: DNL, 2V Range
ERROR (LSB)
ERROR (LSB)
LTC2220: INL, 2V Range
(TA = 25°C unless otherwise noted, Note 4)
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
2220 G05
40
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
2220 G06
22201fa
6
LTC2220/LTC2221
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TYPICAL PERFOR A CE CHARACTERISTICS
LTC2220: SFDR (HD4+) vs Input
Frequency, –1dB, 2V Range,
LVDS Mode
100
90
90
90
80
80
80
70
SFDR (dBFS)
100
70
70
60
60
60
50
50
50
0
100
200
40
300
400
500
600
INPUT FREQUENCY (MHz)
2220 G07
LTC2220: SFDR and SNR
vs Sample Rate, 1V Range,
fIN = 30MHz, –1dB, LVDS Mode
0
100
200
40
300
400
500
600
INPUT FREQUENCY (MHz)
2220 G08
LTC2220: SFDR and SNR
vs Sample Rate, 2V Range,
fIN = 30MHz, –1dB, LVDS Mode
95
90
SFDR
80
75
70
65
SNR
75
70
55
55
50
SNR
80
120
160
SAMPLE RATE (Msps)
200
1V RANGE
220
210
0
40
2220 G10
80
120
160
SAMPLE RATE (Msps)
200
0
2220 G11
40
80
120
160
SAMPLE RATE (Msps)
200
2220 G12
LTC2220: SFDR vs Input Level,
f IN = 70MHz, 2V Range
LTC2220: IOVDD vs Sample Rate,
5MHz Sine Wave Input, –1dB
100
60
90
LVDS OUTPUTS, 0VDD = 3.3V
dBFS
80
SFDR (dBc AND dBFS)
50
40
IOVDD (mA)
40
2V RANGE
250
230
50
0
260
240
65
60
2220 G09
270
80
60
600
280
SFDR
85
SFDR AND SNR (dBFS)
85
200
300
400
500
INPUT FREQUENCY (MHz)
100
290
95
90
0
LTC2220: IVDD vs Sample Rate,
5MHz Sine Wave Input, –1dB
IVDD (mA)
40
SFDR AND SNR (dBFS)
LTC2220: SFDR (HD4+) vs Input
Frequency, –1dB, 1V Range,
LVDS Mode
100
SFDR (dBFS)
SFDR (dBFS)
LTC2220: SFDR (HD2 and HD3)
vs Input Frequency, –1dB, 1V
Range, LVDS Mode
30
20
CMOS OUTPUTS, 0VDD = 1.8V
70
dBc
60
50
40
30
20
10
10
0
0
40
80
120
160
SAMPLE RATE (Msps)
200
2220 G13
0
–60
–50
–30
–20
–40
INPUT LEVEL (dBFS)
–10
0
2220 G14
22201fa
7
LTC2220/LTC2221
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TYPICAL PERFOR A CE CHARACTERISTICS
LTC2220: 8192 Point FFT,
f IN = 30MHz, –1dB, 1V Range,
LVDS Mode
0
–20
–20
–20
–40
–40
–40
–60
–80
–60
–80
–100
–120
10
20
30 40 50 60
FREQUENCY (MHz)
70
–80
–120
0
80
–60
–100
–120
0
10
20
2220 • G15
30 40 50 60
FREQUENCY (MHz)
70
0
80
–20
–20
–20
–40
–40
–40
–100
AMPLITUDE (dB)
0
AMPLITUDE (dB)
0
–80
–60
–80
–100
–120
10
20
30 40 50 60
FREQUENCY (MHz)
70
10
20
2220 • G18
LTC2220: 8192 Point FFT,
f IN = 250MHz, –1dB, 2V
Range, LVDS Mode
–80
30 40 50 60
FREQUENCY (MHz)
70
0
80
–20
–20
–40
–40
–40
AMPLITUDE (dB)
–20
AMPLITUDE (dB)
0
–60
–80
–100
–120
10
20
30 40 50 60
FREQUENCY (MHz)
70
80
2220 • G21
30 40 50 60
FREQUENCY (MHz)
70
80
2220 • G20
–60
–80
–100
–120
0
20
LTC2220: 8192 Point FFT,
f IN = 500MHz, –6dB, 1V
Range, LVDS Mode
0
–100
10
2220 • G19
0
–80
80
2220 • G17
–60
LTC2220: 8192 Point FFT,
f IN = 250MHz, –1dB, 1V
Range, LVDS Mode
–60
70
–120
0
80
30 40 50 60
FREQUENCY (MHz)
–100
–120
0
20
LTC2220: 8192 Point FFT,
f IN = 140MHz, –1dB, 1V
Range, LVDS Mode
0
–60
10
2220 • G16
LTC2220: 8192 Point FFT,
f IN = 140MHz, –1dB, 2V
Range, LVDS Mode
LTC2220: 8192 Point FFT,
f IN = 70MHz, –1dB, 1V Range,
LVDS Mode
AMPLITUDE (dB)
AMPLITUDE (dB)
0
–100
AMPLITUDE (dB)
LTC2220: 8192 Point FFT,
f IN = 70MHz, –1dB, 2V Range,
LVDS Mode
0
AMPLITUDE (dB)
AMPLITUDE (dB)
LTC2220: 8192 Point FFT,
f IN = 30MHz, –1dB, 2V Range,
LVDS Mode
–120
0
10
20
30 40 50 60
FREQUENCY (MHz)
70
80
2220 • G22
0
10
20
30 40 50 60
FREQUENCY (MHz)
70
80
2220 • G23
22201fa
8
LTC2220/LTC2221
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LTC2221: Shorted Input Noise
Histogram
LTC2221: DNL, 2V Range
1.0
1.0
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0
–0.2
100000
0.2
0
–0.4
–0.6
–0.6
–0.8
–0.8
60000
40000
–0.2
–0.4
29529
21767
20000
–1.0
–1.0
0
2048
1024
3072
4096
79331
80000
COUNT
ERROR (LSB)
ERROR (LSB)
LTC2221: INL, 2V Range
2048
1024
OUTPUT CODE
3072
2057
4096
OUTPUT CODE
2221 G01
322
123
0
0
2058
2059
2060
2061
CODE
2221 G02
2221 G03
LTC2221: SNR vs Input
Frequency, –1dB, 1V Range,
LVDS Mode
LTC2221: SNR vs Input
Frequency, –1dB, 2V Range,
LVDS Mode
69
69
67
67
65
65
LTC2221: SFDR (HD2 and HD3)
vs Input Frequency, –1dB, 2V
Range, LVDS Mode
95
90
63
61
SFDR (dBFS)
SNR (dBFS)
SNR (dBFS)
85
63
61
59
59
57
57
80
75
70
65
60
55
55
55
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
50
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
2221 G04
0
90
90
90
85
85
85
80
80
80
SFDR (dBFS)
95
SFDR (dBFS)
95
75
70
75
70
65
65
65
60
60
60
55
55
55
50
50
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
2221 G07
600
LTC2221: SFDR (HD4+) vs Input
Frequency, –1dB, 1V Range,
LVDS Mode
95
70
200
300
400
500
INPUT FREQUENCY (MHz)
2221 G06
LTC2221: SFDR (HD4+) vs Input
Frequency, –1dB, 2V Range,
LVDS Mode
75
100
2221 G05
LTC2221: SFDR (HD2 and HD3)
vs Input Frequency, –1dB, 1V
Range, LVDS Mode
SFDR (dBFS)
600
50
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
2221 G08
0
100
200
300
400
500
INPUT FREQUENCY (MHz)
600
2221 G09
22201fa
9
LTC2220/LTC2221
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LTC2221: SFDR and SNR
vs Sample Rate, 1V Range,
fIN = 30MHz, –1dB, LVDS Mode
LTC2221: IVDD vs Sample Rate,
5MHz Sine Wave Input, –1dB
100
100
220
95
95
210
SFDR
85
80
75
70
SNR
65
90
80
75
20
40
60 80 100 120 140 160
SAMPLE RATE (Msps)
150
0
20
40
60 80 100 120 140 160
SAMPLE RATE (Msps)
2221 G10
0
20
40
60 80 100 120 140 160 180
SAMPLE RATE (Msps)
2221 G12
2221 G11
LTC2221: SFDR vs Input Level,
f IN = 70MHz, 2V Range
LTC2221: IOVDD vs Sample Rate,
5MHz Sine Wave Input, –1dB
60
100
90
LVDS OUTPUTS, OVDD = 3.3V
50
dBFS
SFDR (dBc AND dBFS)
80
40
IOVDD (mA)
1V RANGE
180
160
SNR
60
0
2V RANGE
190
170
70
65
60
200
SFDR
85
IVDD (mA)
90
SFDR AND SNR (dBFS)
SFDR AND SNR (dBFS)
LTC2221: SFDR and SNR
vs Sample Rate, 2V Range,
fIN = 30MHz, –1dB, LVDS Mode
30
20
CMOS OUTPUTS, OVDD = 1.8V
10
70
60
dBc
50
40
30
20
10
0
0
20
40
60 80 100 120 140 160 180
SAMPLE RATE (Msps)
2221 G13
0
–60
–50
–30
–20
–40
INPUT LEVELS (dBFS)
–10
0
2221 G14
22201fa
10
LTC2220/LTC2221
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LTC2221: 8192 Point FFT,
f IN = 30MHz, –1dB, 1V Range,
LVDS Mode
0
0
– 10
– 10
– 20
– 20
– 20
– 30
– 30
– 30
– 40
– 40
– 40
– 50
– 60
– 70
– 80
– 50
– 60
– 70
– 80
– 50
– 60
– 70
– 80
– 90
– 90
– 90
– 100
– 100
– 100
– 110
– 110
– 110
– 120
– 120
– 120
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
2221 G15
2221 G16
LTC2221: 8192 Point FFT,
f IN = 140MHz, –1dB, 2V
Range, LVDS Mode
0
0
– 10
– 10
– 20
– 20
– 20
– 30
– 30
– 30
– 40
– 40
– 40
– 60
– 70
– 80
AMPLITUDE (dB)
0
– 50
– 50
– 60
– 70
– 80
– 50
– 60
– 70
– 80
– 90
– 90
– 90
– 100
– 100
– 100
– 110
– 110
– 110
– 120
– 120
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
FREQUENCY (MHz)
FREQUENCY (MHz)
2221 G18
– 120
0 5 10 15 20 25 30 35 40 45 50 55 60 65
FREQUENCY (MHz)
2221 G19
LTC2221: 8192 Point FFT,
f IN = 250MHz, –1dB, 1V
Range, LVDS Mode
LTC2221: 8192 Point FFT,
f IN = 250MHz, –1dB, 2V
Range, LVDS Mode
0
– 10
– 20
– 20
– 20
– 30
– 30
– 30
– 40
– 40
– 40
– 70
– 80
AMPLITUDE (dB)
0
– 10
AMPLITUDE (dB)
0
– 60
2221 G20
LTC2221: 8192 Point FFT,
f IN = 500MHz, –6dB, 1V
Range, LVDS Mode
– 10
– 50
2221 G17
LTC2221: 8192 Point FFT,
f IN = 140MHz, –1dB, 1V
Range, LVDS Mode
– 10
AMPLITUDE (dB)
AMPLITUDE (dB)
AMPLITUDE (dB)
0
LTC2221: 8192 Point FFT,
f IN = 70MHz, –1dB, 1V Range,
LVDS Mode
AMPLITUDE (dB)
LTC2221: 8192 Point FFT,
f IN = 70MHz, –1dB, 2V Range,
LVDS Mode
– 10
AMPLITUDE (dB)
AMPLITUDE (dB)
LTC2221: 8192 Point FFT,
f IN = 30MHz, –1dB, 2V Range,
LVDS Mode
– 50
– 60
– 70
– 80
– 50
– 60
– 70
– 80
– 90
– 90
– 90
– 100
– 100
– 100
– 110
– 110
– 110
– 120
– 120
– 120
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
2221 G21
2221 G22
2221 G23
22201fa
11
LTC2220/LTC2221
U
U
U
PI FU CTIO S
(CMOS Mode)
AIN+ (Pins 1, 2): Positive Differential Analog Input.
AIN – (Pins 3, 4): Negative Differential Analog Input.
REFHA (Pins 5, 6): ADC High Reference. Bypass to
Pins 7, 8 with 0.1µF ceramic chip capacitor, to Pins 11, 12
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
REFLB (Pins 7, 8): ADC Low Reference. Bypass to Pins 5,
6 with 0.1µF ceramic chip capacitor. Do not connect to
Pins 11, 12.
REFHB (Pins 9, 10): ADC High Reference. Bypass to
Pins 11, 12 with 0.1µF ceramic chip capacitor. Do not
connect to Pins 5, 6.
REFLA (Pins 11, 12): ADC Low Reference. Bypass to
Pins 9, 10 with 0.1µF ceramic chip capacitor, to Pins 5, 6
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
VDD (Pins 13, 14, 15, 62, 63): 3.3V Supply. Bypass to
GND with 0.1µF ceramic chip capacitors.
GND (Pins 16, 61, 64): ADC Power Ground.
ENC+ (Pin 17): Encode Input. Conversion starts on the
positive edge.
ENC – (Pin 18): Encode Complement Input. Conversion
starts on the negative edge. Bypass to ground with 0.1µF
ceramic for single-ended ENCODE signal.
SHDN (Pin 19): Shutdown Mode Selection Pin. Connecting SHDN to GND and OE to GND results in normal
operation with the outputs enabled. Connecting SHDN to
GND and OE to VDD results in normal operation with the
outputs at high impedance. Connecting SHDN to VDD and
OE to GND results in nap mode with the outputs at high
impedance. Connecting SHDN to VDD and OE to VDD
results in sleep mode with the outputs at high impedance.
OE (Pin 20): Output Enable Pin. Refer to SHDN pin
function.
DB0 - DB11 (Pins 21, 22, 23, 24, 27, 28, 29, 30, 31, 32,
35, 36): Digital Outputs, B Bus. DB11 is the MSB. At high
impedance in full rate CMOS mode.
OGND (Pins 25, 33, 41, 50): Output Driver Ground.
OVDD (Pins 26, 34, 42, 49): Positive Supply for the
Output Drivers. Bypass to ground with 0.1µF ceramic chip
capacitor.
OFB (Pin 37): Over/Under Flow Output for B Bus. High
when an over or under flow has occurred. At high impedance in full rate CMOS mode.
CLKOUTB (Pin 38): Data Valid Output for B Bus. In demux
mode with interleaved update, latch B bus data on the
falling edge of CLKOUTB. In demux mode with simultaneous update, latch B bus data on the rising edge of
CLKOUTB. This pin does not become high impedance in
full rate CMOS mode.
CLKOUTA (Pin 39): Data Valid Output for A Bus. Latch A
bus data on the falling edge of CLKOUTA.
DA0 - DA11 (Pins 40, 43, 44, 45, 46, 47, 48, 51, 52, 53,
54, 55): Digital Outputs, A Bus. DA11 is the MSB.
OFA (Pin 56): Over/Under Flow Output for A Bus. High
when an over or under flow has occurred.
LVDS (Pin 57): Output Mode Selection Pin. Connecting
LVDS to 0V selects full rate CMOS mode. Connecting
LVDS to 1/3VDD selects demux CMOS mode with simultaneous update. Connecting LVDS to 2/3VDD selects demux
CMOS mode with interleaved update. Connecting LVDS to
VDD selects LVDS mode.
MODE (Pin 58): Output Format and Clock Duty Cycle
Stabilizer Selection Pin. Connecting MODE to 0V selects
offset binary output format and turns the clock duty cycle
stabilizer off. Connecting MODE to 1/3VDD selects offset
binary output format and turns the clock duty cycle stabilizer on. Connecting MODE to 2/3VDD selects 2’s complement output format and turns the clock duty cycle stabilizer on. Connecting MODE to VDD selects 2’s complement
output format and turns the clock duty cycle stabilizer off.
22201fa
12
LTC2220/LTC2221
U
U
U
PI FU CTIO S
SENSE (Pin 59): Reference Programming Pin. Connecting
SENSE to VCM selects the internal reference and a ±0.5V
input range. Connecting SENSE to VDD selects the internal
reference and a ±1V input range. An external reference
greater than 0.5V and less than 1V applied to SENSE
selects an input range of ±VSENSE. ±1V is the largest valid
input range.
VCM (Pin 60): 1.6V Output and Input Common Mode Bias.
Bypass to ground with 2.2µF ceramic chip capacitor.
GND (Exposed Pad) (Pin 65): ADC Power Ground. The
exposed pad on the bottom of the package needs to be
soldered to ground.
(LVDS Mode)
AIN+ (Pins 1, 2): Positive Differential Analog Input.
AIN– (Pins 3, 4): Negative Differential Analog Input.
REFHA (Pins 5, 6): ADC High Reference. Bypass to
Pins 7, 8 with 0.1µF ceramic chip capacitor, to Pins 11, 12
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
REFLB (Pins 7, 8): ADC Low Reference. Bypass to Pins 5,
6 with 0.1µF ceramic chip capacitor. Do not connect to
Pins 11, 12.
REFHB (Pins 9, 10): ADC High Reference. Bypass to
Pins 11, 12 with 0.1µF ceramic chip capacitor. Do not
connect to Pins 5, 6.
REFLA (Pins 11, 12): ADC Low Reference. Bypass to
Pins 9, 10 with 0.1µF ceramic chip capacitor, to Pins 5, 6
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
VDD (Pins 13, 14, 15, 62, 63): 3.3V Supply. Bypass to
GND with 0.1µF ceramic chip capacitors.
GND (Pins 16, 61, 64): ADC Power Ground.
ENC+ (Pin 17): Encode Input. Conversion starts on the
positive edge.
ENC– (Pin 18): Encode Complement Input. Conversion
starts on the negative edge. Bypass to ground with 0.1µF
ceramic for single-ended ENCODE signal.
SHDN (Pin 19): Shutdown Mode Selection Pin. Connecting SHDN to GND and OE to GND results in normal
operation with the outputs enabled. Connecting SHDN to
GND and OE to VDD results in normal operation with the
outputs at high impedance. Connecting SHDN to VDD and
OE to GND results in nap mode with the outputs at high
impedance. Connecting SHDN to VDD and OE to VDD
results in sleep mode with the outputs at high impedance.
OE (Pin 20): Output Enable Pin. Refer to SHDN pin
function.
D0–/D0+ to D11–/D11+ (Pins 21, 22, 23, 24, 27, 28, 29,
30, 31, 32, 37, 38, 39, 40, 43, 44, 45, 46, 47, 48, 51, 52,
53, 54): LVDS Digital Outputs. All LVDS outputs require
differential 100Ω termination resistors at the LVDS receiver. D11–/D11+ is the MSB.
OGND (Pins 25, 33, 41, 50): Output Driver Ground.
OVDD (Pins 26, 34, 42, 49): Positive Supply for the Output
Drivers. Bypass to ground with 0.1µF ceramic chip
capacitor.
CLKOUT–/CLKOUT+ (Pins 35 to 36): LVDS Data Valid
Output. Latch data on rising edge of CLKOUT–, falling edge
of CLKOUT+.
OF–/OF+ (Pins 55 to 56): LVDS Over/Under Flow Output.
High when an over or under flow has occurred.
LVDS (Pin 57): Output Mode Selection Pin. Connecting
LVDS to 0V selects full rate CMOS mode. Connecting
LVDS to 1/3VDD selects demux CMOS mode with simultaneous update. Connecting LVDS to 2/3VDD selects demux
CMOS mode with interleaved update. Connecting LVDS to
VDD selects LVDS mode.
22201fa
13
LTC2220/LTC2221
U
U
U
PI FU CTIO S
MODE (Pin 58): Output Format and Clock Duty Cycle
Stabilizer Selection Pin. Connecting MODE to 0V selects
offset binary output format and turns the clock duty cycle
stabilizer off. Connecting MODE to 1/3VDD selects offset
binary output format and turns the clock duty cycle stabilizer on. Connecting MODE to 2/3VDD selects 2’s complement output format and turns the clock duty cycle stabilizer on. Connecting MODE to VDD selects 2’s complement
output format and turns the clock duty cycle stabilizer off.
SENSE (Pin 59): Reference Programming Pin. Connecting
SENSE to VCM selects the internal reference and a ±0.5V
input range. Connecting SENSE to VDD selects the internal
reference and a ±1V input range. An external reference
greater than 0.5V and less than 1V applied to SENSE
selects an input range of ±VSENSE. ±1V is the largest valid
input range.
VCM (Pin 60): 1.6V Output and Input Common Mode Bias.
Bypass to ground with 2.2µF ceramic chip capacitor.
GND (Exposed Pad) (Pin 65): ADC Power Ground. The
exposed pad on the bottom of the package needs to be
soldered to ground.
22201fa
14
LTC2220/LTC2221
W
FUNCTIONAL BLOCK DIAGRA
U
U
AIN+
AIN–
VCM
VDD
INPUT
S/H
FIRST PIPELINED
ADC STAGE
SECOND PIPELINED
ADC STAGE
THIRD PIPELINED
ADC STAGE
FOURTH PIPELINED
ADC STAGE
FIFTH PIPELINED
ADC STAGE
GND
1.6V
REFERENCE
2.2µF
SHIFT REGISTER
AND CORRECTION
RANGE
SELECT
SENSE
REFH
REF
BUF
REFL
INTERNAL CLOCK SIGNALS
OVDD
DIFFERENTIAL
INPUT
LOW JITTER
CLOCK
DRIVER
DIFF
REF
AMP
REFLB REFHA
2.2µF
0.1µF
1µF
CONTROL
LOGIC
+
–+
–
D0
CLKOUT
22201 F01
REFLA REFHB
OGND
+
0.1µF
•
•
•
OUTPUT
DRIVERS
+ OF
–+
– D11
ENC
ENC–
M0DE LVDS SHDN
OE
1µF
Figure 1. Functional Block Diagram
22201fa
15
LTC2220/LTC2221
W
UW
TI I G DIAGRA S
LVDS Output Mode Timing
All Outputs Are Differential and Have LVDS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
N+1
tL
ENC –
ENC +
tD
N–5
D0-D11, OF
N–4
N–3
N–2
N–1
tC
CLOCKOUT –
CLOCKOUT +
22201 TD01
Full-Rate CMOS Output Mode Timing
All Outputs Are Single-Ended and Have CMOS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
N+1
tL
ENC –
ENC +
tD
N–5
DA0-DA11, OFA
N–4
N–3
N–2
N–1
tC
CLOCKOUTB
CLOCKOUTA
DB0-DB11, OFB
HIGH IMPEDANCE
22201 TD02
22201fa
16
LTC2220/LTC2221
W
UW
TI I G DIAGRA S
Demultiplexed CMOS Outputs with Interleaved Update
All Outputs Are Single-Ended and Have CMOS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
N+1
tL
ENC –
ENC +
tD
N–5
DA0-DA11, OFA
N–3
N–1
tD
N–6
DB0-DB11, OFB
N–4
tC
N–2
tC
CLOCKOUTB
22201 TD03
CLOCKOUTA
Demultiplexed CMOS Outputs with Simultaneous Update
All Outputs Are Single-Ended and Have CMOS Levels
tAP
ANALOG
INPUT
N+4
N+2
N
N+3
tH
N+1
tL
ENC –
ENC +
tD
DA0-DA11, OFA
N–6
N–4
N–2
N–5
N–3
N–1
tD
DB0-DB11, OFB
tC
CLOCKOUTB
CLOCKOUTA
22201 TD04
22201fa
17
LTC2220/LTC2221
U
U
W
U
APPLICATIO S I FOR ATIO
DYNAMIC PERFORMANCE
input tone to the RMS value of the largest 3rd order
intermodulation product.
Signal-to-Noise Plus Distortion Ratio
The signal-to-noise plus distortion ratio [S/(N + D)] is the
ratio between the RMS amplitude of the fundamental input
frequency and the RMS amplitude of all other frequency
components at the ADC output. The output is band limited
to frequencies above DC to below half the sampling
frequency.
Spurious Free Dynamic Range (SFDR)
Signal-to-Noise Ratio
Full Power Bandwidth
The signal-to-noise ratio (SNR) is the ratio between the
RMS amplitude of the fundamental input frequency and
the RMS amplitude of all other frequency components
except the first five harmonics and DC.
The full power bandwidth is that input frequency at which
the amplitude of the reconstructed fundamental is reduced by 3dB for a full scale input signal.
Spurious free dynamic range is the peak harmonic or
spurious noise that is the largest spectral component
excluding the input signal and DC. This value is expressed
in decibels relative to the RMS value of a full scale input
signal.
Aperture Delay Time
Total Harmonic Distortion
Total harmonic distortion is the ratio of the RMS sum of all
harmonics of the input signal to the fundamental itself. The
out-of-band harmonics alias into the frequency band
between DC and half the sampling frequency. THD is
expressed as:
2
2
2
2
THD = 20Log (√(V2 + V3 + V4 + . . . Vn )/V1)
where V1 is the RMS amplitude of the fundamental frequency and V2 through Vn are the amplitudes of the
second through nth harmonics. The THD calculated in this
data sheet uses all the harmonics up to the fifth.
Intermodulation Distortion
If the ADC input signal consists of more than one spectral
component, the ADC transfer function nonlinearity can
produce intermodulation distortion (IMD) in addition to
THD. IMD is the change in one sinusoidal input caused by
the presence of another sinusoidal input at a different
frequency.
If two pure sine waves of frequencies fa and fb are applied
to the ADC input, nonlinearities in the ADC transfer function can create distortion products at the sum and difference frequencies of mfa ± nfb, where m and n = 0, 1, 2, 3,
etc. The 3rd order intermodulation products are 2fa + fb,
2fb + fa, 2fa – fb and 2fb – fa. The intermodulation
distortion is defined as the ratio of the RMS value of either
The time from when a rising ENC+ equals the ENC– voltage
to the instant that the input signal is held by the sample and
hold circuit.
Aperture Delay Jitter
The variation in the aperture delay time from conversion to
conversion. This random variation will result in noise
when sampling an AC input. The signal to noise ratio due
to the jitter alone will be:
SNRJITTER = –20log (2π • fIN • tJITTER)
CONVERTER OPERATION
As shown in Figure 1, the LTC2220/LTC2221 is a CMOS
pipelined multistep converter. The converter has five
pipelined ADC stages; a sampled analog input will result in
a digitized value five cycles later (see the Timing Diagram
section). For optimal AC performance the analog inputs
should be driven differentially. For cost sensitive applications, the analog inputs can be driven single-ended with
slightly worse harmonic distortion. The encode input is
differential for improved common mode noise immunity.
The LTC2220/LTC2221 has two phases of operation,
determined by the state of the differential ENC+/ENC– input
pins. For brevity, the text will refer to ENC+ greater than
ENC– as ENC high and ENC+ less than ENC– as ENC low.
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Each pipelined stage shown in Figure 1 contains an ADC,
a reconstruction DAC and an interstage residue amplifier.
In operation, the ADC quantizes the input to the stage and
the quantized value is subtracted from the input by the
DAC to produce a residue. The residue is amplified and
output by the residue amplifier. Successive stages operate
out of phase so that when the odd stages are outputting
their residue, the even stages are acquiring that residue
and vice versa.
When ENC is low, the analog input is sampled differentially
directly onto the input sample-and-hold capacitors, inside
the “Input S/H” shown in the block diagram. At the instant
that ENC transitions from low to high, the sampled input
is held. While ENC is high, the held input voltage is
buffered by the S/H amplifier which drives the first pipelined
ADC stage. The first stage acquires the output of the S/H
during this high phase of ENC. When ENC goes back low,
the first stage produces its residue which is acquired by
the second stage. At the same time, the input S/H goes
back to acquiring the analog input. When ENC goes back
high, the second stage produces its residue which is
acquired by the third stage. An identical process is repeated for the third and fourth stages, resulting in a fourth
stage residue that is sent to the fifth stage ADC for final
evaluation.
Each ADC stage following the first has additional range to
accommodate flash and amplifier offset errors. Results
from all of the ADC stages are digitally synchronized such
that the results can be properly combined in the correction
logic before being sent to the output buffer.
When ENC transitions from low to high, the sampled input
voltage is held on the sampling capacitors. During the hold
phase when ENC is high, the sampling capacitors are
disconnected from the input and the held voltage is passed
to the ADC core for processing. As ENC transitions from
high to low, the inputs are reconnected to the sampling
capacitors to acquire a new sample. Since the sampling
capacitors still hold the previous sample, a charging glitch
proportional to the change in voltage between samples will
be seen at this time. If the change between the last sample
and the new sample is small, the charging glitch seen at
the input will be small. If the input change is large, such as
the change seen with input frequencies near Nyquist, then
a larger charging glitch will be seen.
LTC2220/LTC2221
VDD
AIN+
CSAMPLE
1.6pF
15Ω
CPARASITIC
1pF
VDD
AIN–
CSAMPLE
1.6pF
15Ω
CPARASITIC
1pF
VDD
1.6V
6k
ENC+
ENC–
6k
1.6V
22201 F02
SAMPLE/HOLD OPERATION AND INPUT DRIVE
Figure 2. Equivalent Input Circuit
Single-Ended Input
Sample/Hold Operation
Figure 2 shows an equivalent circuit for the LTC2220/
LTC2221 CMOS differential sample-and-hold. The analog
inputs are connected to the sampling capacitors (CSAMPLE)
through NMOS transistors. The capacitors shown attached to each input (CPARASITIC) are the summation of all
other capacitance associated with each input.
During the sample phase when ENC is low, the transistors
connect the analog inputs to the sampling capacitors and
they charge to, and track the differential input voltage.
For cost sensitive applications, the analog inputs can be
driven single-ended. With a single-ended input the harmonic distortion and INL will degrade, but the SNR and
DNL will remain unchanged. For a single-ended input, AIN+
should be driven with the input signal and AIN– should be
connected to 1.6V or VCM.
Common Mode Bias
For optimal performance the analog inputs should be
driven differentially. Each input should swing ±0.5V for
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the 2V range or ±0.25V for the 1V range, around a
common mode voltage of 1.6V. The VCM output pin (Pin
60) may be used to provide the common mode bias level.
VCM can be tied directly to the center tap of a transformer
to set the DC input level or as a reference level to an op amp
differential driver circuit. The VCM pin must be bypassed to
ground close to the ADC with a 2.2µF or greater capacitor.
Input Drive Impedance
As with all high performance, high speed ADCs, the
dynamic performance of the LTC2220/LTC2221 can be
influenced by the input drive circuitry, particularly the
second and third harmonics. Source impedance and input
reactance can influence SFDR. At the falling edge of ENC,
the sample-and-hold circuit will connect the 1.6pF sampling capacitor to the input pin and start the sampling
period. The sampling period ends when ENC rises, holding
the sampled input on the sampling capacitor. Ideally the
input circuitry should be fast enough to fully charge
the sampling capacitor during the sampling period
1/(2FENCODE); however, this is not always possible and the
incomplete settling may degrade the SFDR. The sampling
glitch has been designed to be as linear as possible to
minimize the effects of incomplete settling.
For the best performance, it is recommended to have a
source impedance of 100Ω or less for each input. The
source impedance should be matched for the differential
inputs. Poor matching will result in higher even order
harmonics, especially the second.
Figure 4 demonstrates the use of a differential amplifier to
convert a single ended input signal into a differential input
signal. The advantage of this method is that it provides low
frequency input response; however, the limited gain bandwidth
of most op amps will limit the SFDR at high input frequencies.
Figure 5 shows a single-ended input circuit. The impedance seen by the analog inputs should be matched. This
circuit is not recommended if low distortion is required.
The 25Ω resistors and 12pF capacitor on the analog inputs
serve two purposes: isolating the drive circuitry from the
sample-and-hold charging glitches and limiting the
wideband noise at the converter input. For input frequencies higher than 100MHz, the capacitor may need to be
decreased to prevent excessive signal loss.
VCM
2.2µF
0.1µF
T1
1:1
ANALOG
INPUT
25Ω
25Ω
AIN+
0.1µF
AIN+
12pF
25Ω
AIN–
25Ω
AIN–
T1 = MA/COM ETC1-1T
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
22201 F03
Figure 3. Single-Ended to Differential
Conversion Using a Transformer
VCM
HIGH SPEED
DIFFERENTIAL
AMPLIFIER
ANALOG
INPUT
+
+
2.2µF
AIN+
25Ω
AIN+
3pF
Input Drive Circuits
–
LTC2220/
LTC2221
12pF
CM
Figure 3 shows the LTC2220/LTC2221 being driven by an
RF transformer with a center tapped secondary. The secondary center tap is DC biased with VCM, setting the ADC
input signal at its optimum DC level. Terminating on the
transformer secondary is desirable, as this provides a
common mode path for charging glitches caused by the
sample and hold. Figure 3 shows a 1:1 turns ratio transformer. Other turns ratios can be used if the source
impedance seen by the ADC does not exceed 100Ω for each
ADC input. A disadvantage of using a transformer is the
loss of low frequency response. Most small RF transformers have poor performance at frequencies below 1MHz.
LTC2220/
LTC2221
–
AIN–
25Ω
AIN–
AMPLIFIER = LTC6600-20, LT1993, ETC.
22201 F04
3pF
Figure 4. Differential Drive with an Amplifier
VCM
1k
0.1µF
ANALOG
INPUT
2.2µF
1k
25Ω
AIN+
LTC2220/
LTC2221
AIN+
12pF
25Ω
AIN–
AIN–
0.1µF
22201 F05
Figure 5. Single-Ended Drive
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The AIN+ and AIN– inputs each have two pins to reduce
package inductance. The two AIN+ and the two AIN– pins
should be shorted together.
For input frequencies above 100MHz the input circuits of
Figure 6, 7 and 8 are recommended. The balun transformer gives better high frequency response than a flux
coupled center tapped transformer. The coupling capacitors allow the analog inputs to be DC biased at 1.6V. In
Figure 8 the series inductors are impedance matching
elements that maximize the ADC bandwidth.
VCM
2.2µF
0.1µF
ANALOG
INPUT
25Ω
12Ω
AIN+
0.1µF
AIN+
T1
0.1µF
LTC2220/
LTC2221
8pF
25Ω
AIN–
12Ω
AIN–
T1 = MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
22201 F06
Figure 6. Recommended Front End Circuit for
Input Frequencies Between 100MHz and 250MHz
VCM
2.2µF
0.1µF
AIN+
ANALOG
INPUT
25Ω
AIN+
0.1µF
LTC2220/
LTC2221
Reference Operation
Figure 9 shows the LTC2220/LTC2221 reference circuitry
consisting of a 1.6V bandgap reference, a difference
amplifier and switching and control circuit. The internal
voltage reference can be configured for two pin selectable
input ranges of 2V (±1V differential) or 1V (±0.5V differential). Tying the SENSE pin to VDD selects the 2V range;
typing the SENSE pin to VCM selects the 1V range.
The 1.6V bandgap reference serves two functions: its
output provides a DC bias point for setting the common
mode voltage of any external input circuitry; additionally,
the reference is used with a difference amplifier to generate the differential reference levels needed by the internal
ADC circuitry. An external bypass capacitor is required for
the 1.6V reference output, VCM. This provides a high
frequency low impedance path to ground for internal and
external circuitry.
The difference amplifier generates the high and low reference for the ADC. High speed switching circuits are
connected to these outputs and they must be externally
bypassed. Each output has four pins: two each of REFHA
and REFHB for the high reference and two each of REFLA
and REFLB for the low reference. The multiple output pins
are needed to reduce package inductance. Bypass capacitors must be connected as shown in Figure 9.
T1
0.1µF
LTC2220/LTC2221
AIN–
25Ω
T1 = MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
VCM
1.6V
AIN–
1V
TIE TO VDD FOR 2V RANGE;
TIE TO VCM FOR 1V RANGE;
RANGE = 2 • VSENSE FOR
0.5V < VSENSE < 1V
1µF
2.2µF
4.7nH
25Ω
0.1µF
T1
0.1µF
AIN+
AIN+
LTC2220/
LTC2221
0.5V
RANGE
DETECT
AND
CONTROL
SENSE
REFLB
VCM
0.1µF
1.6V BANDGAP
REFERENCE
2.2µF
22201 F07
Figure 7. Recommended Front End Circuit for
Input Frequencies Between 250MHz and 500MHz
ANALOG
INPUT
4Ω
0.1µF
REFHA
BUFFER
INTERNAL ADC
HIGH REFERENCE
2.2µF
DIFF AMP
2pF
25Ω
4.7nH
AIN–
1µF
REFLA
AIN–
T1 = MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
22201 F08
0.1µF
REFHB
INTERNAL ADC
LOW REFERENCE
22201 F09
Figure 8. Recommended Front End Circuit for
Input Frequencies Above 500MHz
Figure 9. Equivalent Reference Circuit
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Other voltage ranges in between the pin selectable ranges
can be programmed with two external resistors as shown
in Figure 10. An external reference can be used by applying
its output directly or through a resistor divider to SENSE.
It is not recommended to drive the SENSE pin with a logic
device. The SENSE pin should be tied to the appropriate
level as close to the converter as possible. If the SENSE pin
is driven externally, it should be bypassed to ground as
close to the device as possible with a 1µF ceramic capacitor.
1.6V
2. Use as large an amplitude as possible; if transformer
coupled use a higher turns ratio to increase the amplitude.
3. If the ADC is clocked with a sinusoidal signal, filter the
encode signal to reduce wideband noise.
4. Balance the capacitance and series resistance at both
encode inputs so that any coupled noise will appear at both
inputs as common mode noise. The encode inputs have a
common mode range of 1.1V to 2.5V. Each input may be
driven from ground to VDD for single-ended drive.
VCM
LTC2220/LTC2221
2.2µF
VDD
12k
0.8V
12k
SENSE
LTC2220/
LTC2221
TO INTERNAL
ADC CIRCUITS
1µF
VDD
6k
22201 F10
ENC+
Figure 10. 1.6V Range ADC
Input Range
The input range can be set based on the application. The
2V input range will provide the best signal-to-noise performance while maintaining excellent SFDR. The 1V input
range will have better SFDR performance, but the SNR will
degrade by 5dB. See the Typical Performance Characteristics section.
1.6V BIAS
0.1µF
1:4
CLOCK
INPUT
VDD
50Ω
1.6V BIAS
6k
ENC–
22201 F11
Figure 11. Transformer Driven ENC+/ENC–
Driving the Encode Inputs
Maximum and Minimum Encode Rates
The noise performance of the LTC2220/LTC2221 can
depend on the encode signal quality as much as on the
analog input. The ENC+/ENC– inputs are intended to be
driven differentially, primarily for noise immunity from
common mode noise sources. Each input is biased through
a 6k resistor to a 1.6V bias. The bias resistors set the DC
operating point for transformer coupled drive circuits and
can set the logic threshold for single-ended drive circuits.
The maximum encode rate for the LTC2220/LTC2221 is
170Msps (LTC2220) and 135Msps (LTC2221). For the
ADC to operate properly, the encode signal should have a
50% (±5%) duty cycle. Each half cycle must have at least
2.8ns (LTC2220) or 3.5ns (LTC2221) for the ADC internal
circuitry to have enough settling time for proper operation.
Achieving a precise 50% duty cycle is easy with differential
sinusoidal drive using a transformer or using symmetric
differential logic such as PECL or LVDS.
Any noise present on the encode signal will result in
additional aperture jitter that will be RMS summed with the
inherent ADC aperture jitter.
In applications where jitter is critical (high input frequencies) take the following into consideration:
1. Differential drive should be used.
An optional clock duty cycle stabilizer circuit can be used
if the input clock has a non 50% duty cycle. This circuit
uses the rising edge of the ENC+ pin to sample the analog
input. The falling edge of ENC+ is ignored and the internal
falling edge is generated by a phase-locked loop. The input
clock duty cycle can vary from 30% to 70% and the clock
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duty cycle stabilizer will maintain a constant 50% internal
duty cycle. If the clock is turned off for a long period of
time, the duty cycle stabilizer circuit will require one
hundred clock cycles for the PLL to lock onto the input
clock. To use the clock duty cycle stabilizer, the MODE pin
should be connected to 1/3VDD or 2/3VDD using external
resistors.
The lower limit of the LTC2220/LTC2221 sample rate is
determined by droop of the sample-and-hold circuits. The
pipelined architecture of this ADC relies on storing analog
signals on small valued capacitors. Junction leakage will
discharge the capacitors. The specified minimum operating frequency for the LTC2220/LTC2221 is 1Msps.
ENC+
VTHRESHOLD = 1.6V
1.6V ENC–
LTC2220/
LTC2221
Digital Output Modes
The LTC2220/LTC2221 can operate in several digital output modes: LVDS, CMOS running at full speed, and CMOS
demultiplexed onto two buses, each of which runs at half
speed. In the demultiplexed CMOS modes the two buses
(referred to as bus A and bus B) can either be updated on
alternate clock cycles (interleaved mode) or simultaneously
(simultaneous mode). For details on the clock timing, refer
to the timing diagrams.
The LVDS pin selects which digital output mode the part
uses. This pin has a four-level logic input which should be
connected to GND, 1/3VDD, 2/3VDD or VDD. An external
resistor divider can be used to set the 1/3VDD or 2/3VDD
logic values. Table 2 shows the logic states for the LVDS
pin.
Table 2. LVDS Pin Function
0.1µF
LVDS
Digital Output Mode
GND
Full-Rate CMOS
1/3VDD
Demultiplexed CMOS, Simultaneous Update
2/3VDD
Demultiplexed CMOS, Interleaved Update
VDD
LVDS
22201 F12Ía
Figure 12a. Single-Ended ENC Drive,
Not Recommended for Low Jitter
3.3V
MC100LVELT22
3.3V
130Ω
Q0
130Ω
Digital Output Buffers (CMOS Modes)
ENC+
D0
ENC–
Q0
83Ω
LTC2220/
LTC2221
83Ω
22201 F12b
Figure 12b. ENC Drive Using a CMOS to PECL Translator
DIGITAL OUTPUTS
Table 1. Output Codes vs Input Voltage
AIN+ – AIN–
(2V Range)
OF
D11 – D0
(Offset Binary)
D11 – D0
(2’s Complement)
>+1.000000V
+0.999512V
+0.999024V
1
0
0
1111 1111 1111
1111 1111 1111
1111 1111 1110
0111 1111 1111
0111 1111 1111
0111 1111 1110
+0.000488V
0.000000V
–0.000488V
–0.000976V
0
0
0
0
1000 0000 0001
1000 0000 0000
0111 1111 1111
0111 1111 1110
0000 0000 0001
0000 0000 0000
1111 1111 1111
1111 1111 1110
–0.999512V
–1.000000V
<–1.000000V
0
0
1
0000 0000 0001
0000 0000 0000
0000 0000 0000
1000 0000 0001
1000 0000 0000
1000 0000 0000
Figure 13a shows an equivalent circuit for a single output
buffer in the CMOS output mode. Each buffer is powered
by OVDD and OGND, which are isolated from the ADC
power and ground. The additional N-channel transistor in
the output driver allows operation down to voltages as low
as 0.5V. The internal resistor in series with the output
makes the output appear as 50Ω to external circuitry and
may eliminate the need for external damping resistors.
LTC2220/LTC2221
OVDD
VDD
0.5V
TO 3.6V
VDD
0.1µF
OVDD
DATA
FROM
LATCH
PREDRIVER
LOGIC
43Ω
TYPICAL
DATA
OUTPUT
OE
OGND
22201 F13a
Figure 13a. Digital Output Buffer in CMOS Mode
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As with all high speed/high resolution converters, the
digital output loading can affect the performance. The
digital outputs of the LTC2220/LTC2221 should drive a
minimal capacitive load to avoid possible interaction between the digital outputs and sensitive input circuitry. The
output should be buffered with a device such as an
ALVCH16373 CMOS latch. For full speed operation the
capacitive load should be kept under 10pF.
Lower OVDD voltages will also help reduce interference
from the digital outputs.
Digital Output Buffers (LVDS Mode)
The LTC2220/LTC2221 parallel digital output can be selected for offset binary or 2’s complement format. The
format is selected with the MODE pin. Connecting MODE
to GND or 1/3VDD selects offset binary output format.
Connecting MODE to 2/3VDD or VDD selects 2’s complement output format. An external resistor divider can be
used to set the 1/3VDD or 2/3VDD logic values. Table 3
shows the logic states for the MODE pin.
Table 3. MODE Pin Function
Output Format
Clock Duty
Cycle Stablizer
0
Offset Binary
Off
1/3VDD
Offset Binary
On
2/3VDD
2’s Complement
On
VDD
2’s Complement
Off
MODE Pin
Figure 13b shows an equivalent circuit for a differential
output pair in the LVDS output mode. A 3.5mA current is
steered from OUT+ to OUT– or vice versa which creates a
±350mV differential voltage across the 100Ω termination
resistor at the LVDS receiver. A feedback loop regulates
the common mode output voltage to 1.25V. For proper
operation each LVDS output pair needs an external 100Ω
termination resistor, even if the signal is not used (such as
OF+/OF– or CLKOUT+/CLKOUT–). To minimize noise the
PC board traces for each LVDS output pair should be
routed close together. To minimize clock skew all LVDS PC
board traces should have about the same length.
LTC2220/LTC2221
Data Format
Overflow Bit
An overflow output bit indicates when the converter is
overranged or underranged. In CMOS mode, a logic high
on the OFA pin indicates an overflow or underflow on the
A data bus, while a logic high on the OFB pin indicates an
overflow or underflow on the B data bus. In LVDS mode,
a differential logic high on the OF+/OF– pins indicates an
overflow or underflow.
OVDD
Output Clock
D
OUT+
–
+
D
10k
10k
100Ω
1.25V
OUT–
D
D
3.5mA
OGND
22201 F13b
Figure 13b. Digital Output in LVDS Mode
LVDS
RECEIVER
The ADC has a delayed version of the ENC+ input available
as a digital output, CLKOUT. The CLKOUT pin can be used
to synchronize the converter data to the digital system. This
is necessary when using a sinusoidal encode. In all CMOS
modes, A bus data will be updated just after CLKOUTA rises
and can be latched on the falling edge of CLKOUTA. In demux
CMOS mode with interleaved update, B bus data will be
updated just after CLKOUTB rises and can be latched on the
falling edge of CLKOUTB. In demux CMOS mode with simultaneous update, B bus data will be updated just after
CLKOUTB falls and can be latched on the rising edge of
CLKOUTB. In LVDS mode, data will be updated just after
CLKOUT+/CLKOUT– rises and can be latched on the falling
edge of CLKOUT+/CLKOUT–.
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Output Driver Power
Separate output power and ground pins allow the output
drivers to be isolated from the analog circuitry. The power
supply for the digital output buffers, OVDD, should be tied
to the same power supply as for the logic being driven. For
example if the converter is driving a DSP powered by a 1.8V
supply then OVDD should be tied to that same 1.8V supply.
In the CMOS output mode, OVDD can be powered with any
voltage up to 3.6V. OGND can be powered with any voltage
from GND up to 1V and must be less than OVDD. The logic
outputs will swing between OGND and OVDD.
In the LVDS output mode, OVDD should be connected to a
3.3V supply and OGND should be connected to GND.
Output Enable
The outputs may be disabled with the output enable pin, OE.
In CMOS or LVDS output modes OE high disables all data
outputs including OF and CLKOUT. The data access and bus
relinquish times are too slow to allow the outputs to be
enabled and disabled during full speed operation. The output
Hi-Z state is intended for use during long periods of
inactivity.
The Hi-Z state is not a truly open circuit; the output pins that
make an LVDS output pair have a 20k resistance between
them. Therefore in the CMOS output mode, adjacent data
bits will have 20k resistance in between them, even in the
Hi-Z state.
Sleep and Nap Modes
The converter may be placed in shutdown or nap modes
to conserve power. Connecting SHDN to GND results in
normal operation. Connecting SHDN to VDD and OE to VDD
results in sleep mode, which powers down all circuitry
including the reference and typically dissipates 1mW. When
exiting sleep mode it will take milliseconds for the output
data to become valid because the reference capacitors have
to recharge and stabilize. Connecting SHDN to VDD and OE
to GND results in nap mode, which typically dissipates
35mW. In nap mode, the on-chip reference circuit is kept
on, so that recovery from nap mode is faster than that from
sleep mode, typically taking 100 clock cycles. In both sleep
and nap mode all digital outputs are disabled and enter the
Hi-Z state.
GROUNDING AND BYPASSING
The LTC2220/LTC2221 requires a printed circuit board with
a clean unbroken ground plane. A multilayer board with an
internal ground plane is recommended. Layout for the
printed circuit board should ensure that digital and analog
signal lines are separated as much as possible. In particular, care should be taken not to run any digital signal alongside an analog signal or underneath the ADC.
High quality ceramic bypass capacitors should be used at
the VDD, OVDD, VCM, REFHA, REFHB, REFLA and REFLB pins
as shown in the block diagram on the front page of this data
sheet. Bypass capacitors must be located as close to the
pins as possible. Of particular importance are the capacitors between REFHA and REFLB and between REFHB and
REFLA. These capacitors should be as close to the device
as possible (1.5mm or less). Size 0402 ceramic capacitors
are recommended. The 2.2µF capacitor between REFHA and
REFLA can be somewhat further away. The traces connecting the pins and bypass capacitors must be kept short and
should be made as wide as possible.
The LTC2220/LTC2221 differential inputs should run parallel and close to each other. The input traces should be as
short as possible to minimize capacitance and to minimize
noise pickup.
HEAT TRANSFER
Most of the heat generated by the LTC2220/LTC2221 is
transferred from the die through the bottom-side exposed
pad and package leads onto the printed circuit board. For
good electrical and thermal performance, the exposed pad
should be soldered to a large grounded pad on the PC board.
It is critical that all ground pins are connected to a ground
plane of sufficient area.
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Clock Sources for Undersampling
Undersampling raises the bar on the clock source and the
higher the input frequency, the greater the sensitivity to
clock jitter or phase noise. A clock source that degrades
SNR of a full-scale signal by 1dB at 70MHz will degrade
SNR by 3dB at 140MHz, and 4.5dB at 190MHz.
In cases where absolute clock frequency accuracy is
relatively unimportant and only a single ADC is required,
a 3V canned oscillator from vendors such as Saronix or
Vectron can be placed close to the ADC and simply
connected directly to the ADC. If there is any distance to
the ADC, some source termination to reduce ringing that
may occur even over a fraction of an inch is advisable. You
must not allow the clock to overshoot the supplies or
performance will suffer. Do not filter the clock signal with
a narrow band filter unless you have a sinusoidal clock
source, as the rise and fall time artifacts present in typical
digital clock signals will be translated into phase noise.
The lowest phase noise oscillators have single-ended
sinusoidal outputs, and for these devices the use of a filter
close to the ADC may be beneficial. This filter should be
close to the ADC to both reduce roundtrip reflection times,
as well as reduce the susceptibility of the traces between
the filter and the ADC. If you are sensitive to close-in phase
noise, the power supply for oscillators and any buffers
must be very stable, or propagation delay variation with
supply will translate into phase noise. Even though these
clock sources may be regarded as digital devices, do not
operate them on a digital supply. If your clock is also used
to drive digital devices such as an FPGA, you should locate
the oscillator, and any clock fan-out devices close to the
ADC, and give the routing to the ADC precedence. The
clock signals to the FPGA should have series termination
at the source to prevent high frequency noise from the
FPGA disturbing the substrate of the clock fan-out device.
If you use an FPGA as a programmable divider, you must
re-time the signal using the original oscillator, and the retiming flip-flop as well as the oscillator should be close to
the ADC, and powered with a very quiet supply.
For cases where there are multiple ADCs, or where the
clock source originates some distance away, differential
clock distribution is advisable. This is advisable both from
the perspective of EMI, but also to avoid receiving noise
from digital sources both radiated, as well as propagated
in the waveguides that exist between the layers of multilayer PCBs. The differential pairs must be close together,
and distanced from other signals. The differential pair
should be guarded on both sides with copper distanced at
least 3x the distance between the traces, and grounded
with vias no more than 1/4 inch apart.
22201fa
26
VCM
R27
50Ω
J9
R29
1k
1/3VDD
R30
1k
GND
ANALOG
INPUT
MODE
R28
1k
2/3VDD
VDD
C7
12pF
C23
0.1µF
C27
0.1µF
JP7
T1*
ETC1-1T
C39
0.1µF
R11
24.9Ω
AIN–
AIN+
C30
0.1µF
C31
0.1µF
C32
0.1µF
C33
0.1µF
C34
4.7µF
56
55
54
53
52
51
48
47
46
45
44
43
40
39
38
37
36
35
32
31
30
29
28
27
24
23
22
21
49
42
34
26
VDD
ENCODE
INPUT
VDD
3.3V
J6
R25
100Ω
R14
100Ω
PWR GND
GND
R26
100Ω
R13
100Ω
VDD
R7
100Ω
C26
0.1µF
R2
4.99k 1%
R21
100Ω
1
A0
2
A1
3
A2
4
A3
R8
100Ω
CLK
C25
33pF
CLK
R4
4.99k 1%
SDA
SCL
VSS
VCC_IN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
GND
GND
EN/12
RIN1–
RIN1+
RIN2+
RIN2–
RIN3–
RIN3+
RIN4+
RIN4–
VCC
EN
RIN5–
RIN5+
RIN6+
RIN6–
RIN7–
RIN7+
RIN8+
RIN8–
EN/34
GND
VBB
C1
0.1µF
VCC
VCC
EN/78
DOUT1–
DOUT1+
DOUT2+
DOUT2–
DOUT3–
DOUT3+
DOUT4+
DOUT4–
GND
GND
DOUT5–
DOUT5+
DOUT6+
DOUT6–
DOUT7–
DOUT7+
DOUT8+
DOUT8–
EN/56
VCC
VCC
VCC
VCC
EN/78
DOUT1–
DOUT1+
DOUT2+
DOUT2–
DOUT3–
DOUT3+
DOUT4+
DOUT4–
GND
GND
DOUT5–
DOUT5+
DOUT6+
DOUT6–
DOUT7–
DOUT7+
DOUT8+
DOUT8–
EN/56
VCC
VCC
C2
0.1µF
U2 FINII08
OPT
VCC
VCC 3.3V
VCC
VCC
Evaluation Circuit Schematic of the LTC2220
C20
0.1µF
JP4
8
VCC
7
WP
6
SCL
5
SDA
ENABLE
R20
100Ω
R18
100Ω
R3
4.99k 1%
R19 100Ω
R17
100Ω
U4 24LCO25
C4
0.1µF
R23
100Ω
R16
100Ω
T2
ETC1-1T
C3
4.7µF
R24
100Ω
R15
100Ω
* FOR AIN > 100MHz, REPLACE T1 WITH A ETC1-1-13
R12
24.9Ω
R10
24.9Ω
R9
24.9Ω
C22
0.1µF
1
2
3
4
AIN–
5
6
C16
C17
0.1µF 7
1µF
8
C19
2.2µF
9
10
C18
C11
VDD
1µF
0.1µF 11
12
C21
62
0.1µF
63
13
VDD
14
15
C24
VDD JP3
0.1µF
17
CLK
18
GND
SHDN
CLK
19
20
25
C29
33
2.2µF
VDD
GND
41
VDD
50
0E
JP1
60
VCM
JP20
SENSE
59
VDD
16
VCM
61
VCM
64
EXT
58
REF
57
C35
VDD
0.1µF
AIN+
LTC2220
AIN+
OF+/OFA
AIN+
OF–/DA11
AIN–
D11+/DA10
AIN–
D11–/DA9
REFHA
D10+/DA8
REFHA
D10–/DA7
REFLB
D9+/DA6
REFLB
D9–/DA5
REFHB
D8+/DA4
REFHB
D8–/DA3
REFLA
D7+/DA2
REFLA
D7–/DA1
VDD
D6+/DA0
VDD D6–/CLKOUTA
VDD D5+/CLKOUTB
VDD
DB5–/OFB
VDD CLKOUT+/DB11
+
ENC CLKOUT–/DB10
ENC–
D4+/DB9
SHDN
D4–/DB8
OEL
D3+/DB7
OGND
D3–/DB6
OGND
D2+/DB5
OGND
D2–/DB4
OGND
D1+/DB3
VCM
D1–/DB2
SENSE
D0+/DB1
GND
D0–/DB0
GND
OVDD
GND
OVDD
MODE
OVDD
LVDS
OVDD
GND
GND
EN/12
RIN1–
RIN1+
RIN2+
RIN2–
RIN3–
RIN3+
RIN4+
RIN4–
VCC
EN
RIN5–
RIN5+
RIN6+
RIN6–
RIN7–
RIN7+
RIN8+
RIN8–
EN/34
GND
VBB
U1 FINII08
VCC
C6
0.1µF
C5
4.7µF
C8
0.1µF
L1
VCC
MURATA
BLM18BB470SN
C5
0.1µF
VDD
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
VCC
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
C9
0.1µF
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
51
53
55
57
59
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89
91
93
95
97
99
C10
0.1µF
EDGE-CON-100
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
C12
0.1µF
R6
4.7k
C36
4.7µF
VCC
ENABLE
SDA
VCC_IN
VSS
SCL
U U
W
U3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
APPLICATIO S I FOR ATIO
U
R1
100Ω
LTC2220/LTC2221
22201fa
27
LTC2220/LTC2221
U
W
U U
APPLICATIO S I FOR ATIO
Silkscreen Top
22201fa
28
LTC2220/LTC2221
U
W
U U
APPLICATIO S I FOR ATIO
Layer 1 Component Side
Layer 2 GND Plane
22201fa
29
LTC2220/LTC2221
U
W
U U
APPLICATIO S I FOR ATIO
Layer 3 Power Plane
Layer 4 Bottom Side
22201fa
30
LTC2220/LTC2221
U
PACKAGE DESCRIPTIO
UP Package
64-Lead Plastic QFN (9mm × 9mm)
(Reference LTC DWG # 05-08-1705)
0.70 ±0.05
7.15 ±0.05
8.10 ±0.05 9.50 ±0.05
(4 SIDES)
PACKAGE OUTLINE
0.25 ±0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
9 .00 ± 0.10
(4 SIDES)
0.75 ± 0.05
R = 0.115
TYP
63 64
0.40 ± 0.10
PIN 1 TOP MARK
(SEE NOTE 5)
1
2
PIN 1
CHAMFER
7.15 ± 0.10
(4-SIDES)
0.25 ± 0.05
0.200 REF
0.00 – 0.05
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION WNJR-5
2. ALL DIMENSIONS ARE IN MILLIMETERS
3. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE, IF PRESENT
4. EXPOSED PAD SHALL BE SOLDER PLATED
5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
6. DRAWING NOT TO SCALE
(UP64) QFN 1003
0.50 BSC
BOTTOM VIEW—EXPOSED PAD
22201fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
31
LTC2220/LTC2221
RELATED PARTS
PART NUMBER
DESCRIPTION
LTC1748
14-Bit, 80Msps, 5V ADC
76.3dB SNR, 90dB SFDR, 48-Pin TSSOP Package
LTC1750
14-Bit, 80Msps, 5V Wideband ADC
Up to 500MHz IF Undersampling, 90dB SFDR
LT1993-2
High Speed Differential Op Amp
800MHz BW, 70dBc Distortion at 70MHz, 6dB Gain
LT 1994
Low Noise, Low Distortion Fully Differential Input/
Output Amplifier/Driver
Low Distortion: –94dBc at 1MHz
LTC2202
16-Bit, 10Msps, 3.3V ADC, Lowest Noise
150mW, 81.6dB SNR, 100dB SFDR, 48-pin QFN
LTC2208
16-Bit, 130Msps, 3.3V ADC, LVDS Outputs
1250mW, 78dB SNR, 100dB SFDR, 64-pin QFN
LTC2220
12-Bit, 170Msps, 3.3V ADC, LVDS Outputs
890mW, 67.7dB SNR, 84dB SFDR, 64-pin QFN
LTC2220-1
12-Bit, 185Msps, 3.3V ADC, LVDS Outputs
910mW, 67.7dB SNR, 80dB SFDR, 64-pin QFN
LTC2221
12-Bit, 135Msps, 3.3V ADC, LVDS Outputs
660mW, 67.8dB SNR, 84dB SFDR, 64-pin QFN
LTC2224
12-Bit, 135Msps, 3.3V ADC, High IF Sampling
630mW, 67.6dB SNR, 84dB SFDR, 48-pin QFN
LTC2230
10-Bit, 170Msps, 3.3V ADC, LVDS Outputs
890mW, 61.2dB SNR, 78dB SFDR, 64-pin QFN
LTC2231
10-Bit, 135Msps, 3.3V ADC, LVDS Outputs
660mW, 61.2dB SNR, 78dB SFDR, 64-pin QFN
LTC2255
14-Bit, 125Msps, 3V ADC, Lowest Power
395mW, 72.5dB SNR, 88dB SFDR, 32-pin QFN
LTC2284
14-Bit, Dual, 105Msps, 3V ADC, Low Crosstalk
540mW, 72.4dB SNR, 88dB SFDR, 64-pin QFN
LT5512
DC-3GHz High Signal Level Downconverting Mixer
DC to 3GHz, 21dBm IIP3, Integrated LO Buffer
LT5514
Ultralow Distortion IF Amplifier/ADC Driver with Digitally
Controlled Gain
450MHz to 1dB BW, 47dB OIP3, Digital Gain Control
10.5dB to 33dB in 1.5dB/Step
LT5515
1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator
High IIP3: 20dBm at 1.9GHz, Integrated LO Quadrature Generator
LT5516
800MHz to 1.5GHz Direct Conversion Quadrature Demodulator High IIP3: 21.5dBm at 900MHz, Integrated LO Quadrature Generator
LT5517
40MHz to 900MHz Direct Conversion Quadrature Demodulator High IIP3: 21dBm at 800MHz, Integrated LO Quadrature Generator
LT5522
600MHz to 2.7GHz High Linearity Downconverting Mixer
®
COMMENTS
4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz. NF = 12.5dB, 50Ω
Single Ended RF and LO Ports
22201fa
32
Linear Technology Corporation
LT 0106 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2004