查询LTC1747IFW供应商
FEATURES
■
Sample Rate: 80Msps
■
PGA Front End (2.25V
■
71.8dB SNR and 87dB SFDR (PGA = 0)
■
70.2dB SNR and 87dB SFDR (PGA = 1)
■
500MHz Full Power Bandwidth S/H
■
No Missing Codes
■
Single 5V Supply
■
Power Dissipation: 1.45W
■
Two Pin Selectable Reference Values
■
Data Ready Output Clock
■
Pin Compatible 14-Bit 80Msps Device (LTC1750)
■
48-Pin TSSOP Package
or 1.35V
P-P
Input Range)
P-P
U
APPLICATIO S
■
Direct IF Sampling
■
Telecommunications
■
Receivers
■
Cellular Base Stations
■
Spectrum Analysis
■
Communications Test Equipment
■
Undersampling
LTC1749
12-Bit, 80Msps
Wide Bandwidth ADC
U
DESCRIPTIO
The LTC®1749 is an 80Msps, 12-bit A/D converter designed for digitizing wide dynamic range signals up to
frequencies of 500MHz. The input range of the ADC can be
optimized with the on-chip PGA sample-and-hold circuit
and flexible reference circuitry.
The LTC1749 has a highly linear sample-and-hold circuit
with a bandwidth of 500MHz. The SFDR is 80dB with an
input frequency of 250MHz. Ultralow jitter of 0.15ps
allows undersampling of IF frequencies with minimal
degradation in SNR. DC specs include ±1LSB INL and no
missing codes.
The digital interface is compatible with 5V, 3V, 2V and
LVDS logic systems. The ENC and ENC inputs may be
driven differentially from PECL, GTL and other low swing
logic families or from single-ended TTL or CMOS. The low
noise, high gain ENC and ENC inputs may also be driven
by a sinusoidal signal without degrading performance. A
separate output power supply can be operated from 0.5V
to 5V, making it easy to connect directly to low voltage
DSPs or FIFOs.
The 48-pin TSSOP package with a flow-through pinout
simplifies the board layout.
, LTC and LT are registered trademarks of Linear Technology Corporation.
RMS
BLOCK DIAGRA
PGA
+
A
IN
±1.125V
DIFFERENTIAL
ANALOG INPUT
4.7µF
A
SENSE
V
–
IN
RANGE
SELECT
CM
2V
REF
W
80Msps, 12-Bit ADC with a 2.25V Differential Input Range
CORRECTION
LOGIC AND
SHIFT
REGISTER
CONTROL LOGIC
ENC
0.1µF0.1µF
DIFFERENTIAL
ENCODE INPUT
BUFFER
S/H
CIRCUIT
DIFF AMP
1µF1µF
12-BIT
PIPELINED ADC
REFHAREFLB
4.7µF
REFLA REFHB
12
ENC
OUTPUT
LATCHES
MSBINV
OV
DD
0.1µF
D11
•
•
•
D0
CLKOUT
OGND
V
DD
1µF 1µF 1µF
GND
1749 BD
0.5V TO 5V
0.1µF
5V
1749f
1
LTC1749
WW
W
U
ABSOLUTE MAXIMUM RATINGS
OVDD = VDD (Notes 1, 2)
Supply Voltage (VDD)............................................. 5.5V
Analog Input Voltage (Note 3) .... – 0.3V to (VDD + 0.3V)
Digital Input Voltage (Note 4) ..... –0.3V to (VDD + 0.3V)
Digital Output Voltage................. – 0.3V to (VDD + 0.3V)
OGND Voltage..............................................–0.3V to 1V
Power Dissipation............................................ 2000mW
Operating Temperature Range
LTC1749C ............................................... 0°C to 70°C
LTC1749I............................................ – 40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
U
W
U
PACKAGE/ORDER INFORMATION
TOP VIEW
SENSE
V
GND
A
A
GND
V
V
GND
REFLB
REFHA
GND
GND
REFLA
REFHB
GND
V
V
GND
V
GND
MSBINV
ENC
ENC
1
2
CM
3
+
4
IN
–
5
IN
6
7
DD
8
DD
9
10
11
12
13
14
15
16
17
DD
18
DD
19
20
DD
21
22
23
24
FW PACKAGE
48-LEAD PLASTIC TSSOP
T
= 150°C, θJA = 35°C/W
JMAX
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
OF
OGND
D11
D10
D9
OV
DD
D8
D7
D6
D5
OGND
GND
GND
D4
D3
D2
OV
DD
D1
D0
NC
NC
OGND
CLKOUT
PGA
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ORDER PART
NUMBER
LTC1749CFW
LTC1749IFW
U
CO VERTER CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C. (Note 5)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Resolution (No Missing Codes) ● 12 Bits
Integral Linearity Error (Note 6) – 1.0 ±0.4 1.0 LSB
Differential Linearity Error ● –0.8 ±0.2 0.8 LSB
Offset Error (Note 7) External Reference (V
Gain Error External Reference (V
Full-Scale Tempco Internal Reference ±40 ppm/°C
Offset Tempco ±20 µV/°C
Input Referred Noise (Transition Noise) V
External Reference (V
= 1.125V, PGA = 0 0.23 LSB
SENSE
The ● indicates specifications which apply over the full operating
● –1.5 1.5 LSB
= 1.125V, PGA = 0) –35 ±835 mV
SENSE
= 1.125V, PGA = 0) –3.5 ±1 3.5 %FS
SENSE
= 1.125V) ±20 ppm/°C
SENSE
RMS
UU
A ALOG I PUT
specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
I
IN
C
IN
t
ACQ
t
AP
t
JITTER
CMRR Analog Input Common Mode Rejection Ratio 1.5V < (A
Analog Input Range (Note 8) 4.75V ≤ VDD ≤ 5.25V ● ±0.7 to ±1.125 V
Analog Input Leakage Current 0 < A
Analog Input Capacitance Sample Mode ENC < ENC 6.9 pF
Sample-and-Hold Acquisition Time ● 56ns
Sample-and-Hold Acquisition Delay Time 0 ns
Sample-and-Hold Acquisition Delay Time Jitter 0.15 ps
The ● indicates specifications which apply over the full operating temperature range, otherwise
+
–
, A
< V
IN
IN
DD
Hold Mode ENC > ENC 2.4 pF
–
+
= A
IN
) < 3V 80 dB
IN
● –1 1 µA
RMS
1749f
2
LTC1749
UW
DY A IC ACCURACY
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
SNR Signal-to-Noise Ratio 5MHz Input Signal (PGA = 0) 71.8 dB
SFDR Spurious Free Dynamic Range 5MHz Input Signal (PGA = 0) 87 dB
S/(N + D) Signal-to-(Noise + Distortion) Ratio 5MHz Input Signal (PGA = 0) 71.7 dB
THD Total Harmonic Distortion 5MHz Input Signal, First 5 Harmonics (PGA = 0) –87 dB
IMD Intermodulation Distortion f
Sample-and-Hold Bandwidth R
TA = 25°C, AIN = –1dBFS (Note 5), V
5MHz Input Signal (PGA = 1) 70.2 dB
30MHz Input Signal (PGA = 0) 70.5 71.7 dB
30MHz Input Signal (PGA = 1) 70.2 dB
70MHz Input Signal (PGA = 0) 71.4 dB
70MHz Input Signal (PGA = 1) 68.8 70.1 dB
140MHz Input Signal (PGA = 1) 69.8 dB
250MHz Input Signal (PGA = 1) 69.3 dB
350MHz Input Signal (PGA = 1) 67.4 dB
5MHz Input Signal (PGA = 1) 87 dB
30MHz Input Signal (PGA = 0) (HD2 and HD3) 76 87 dB
30MHz Input Signal (PGA = 0) (Other) 83 90 dB
70MHz Input Signal (PGA = 0) 85 dB
70MHz Input Signal (PGA = 1) (HD2 and HD3) 76 87 dB
70MHz Input Signal (PGA = 1) (Other) 83 90 dB
140MHz Input Signal (PGA = 1) 84 dB
250MHz Input Signal (PGA = 1) 80 dB
350MHz Input Signal (PGA = 1) 74 dB
5MHz Input Signal (PGA = 1) 70.1 dB
30MHz Input Signal (PGA = 0) 71.6 dB
30MHz Input Signal (PGA = 1) 70.0 dB
70MHz Input Signal (PGA = 0) 71.2 dB
70MHz Input Signal (PGA = 1) 69.9 dB
250MHz Input Signal (PGA = 1) 68.6 dB
5MHz Input Signal, First 5 Harmonics (PGA = 1) –87 dB
30MHz Input Signal, First 5 Harmonics (PGA = 0) –87 dB
30MHz Input Signal, First 5 Harmonics (PGA = 1) –87 dB
70MHz Input Signal, First 5 Harmonics (PGA = 0) –85 dB
70MHz Input Signal, First 5 Harmonics (PGA = 1) –87 dB
250MHz Input Signal (PGA = 1) 78 dB
= 2.52MHz, f
IN1
= 2.52MHz, f
f
IN1
= 50Ω 500 MHz
SOURCE
= 5.2MHz (PGA = 0) –87 dBc
IN2
= 5.2MHz (PGA = 1) –87 dBc
IN2
SENSE
= V
DD
UU U
I TER AL REFERE CE CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
VCM Output Voltage I
VCM Output Tempco I
VCM Line Regulation 4.75V ≤ VDD ≤ 5.25V 3 mV/V
VCM Output Resistance 1mA ≤ I
= 0 1.95 2 2.05 V
OUT
= 0 ±30 ppm/°C
OUT
≤ 1mA 4 Ω
OUT
(Note 5)
1749f
3
LTC1749
UU
DIGITAL I PUTS A D DIGITAL OUTPUTS
operating temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IH
V
IL
I
IN
C
IN
V
OH
V
OL
I
SOURCE
I
SINK
High Level Input Voltage VDD = 5.25V, MSBINV and PGA ● 2.4 V
Low Level Input Voltage VDD = 4.75V, MSBINV and PGA ● 0.8 V
Digital Input Current VIN = 0V to V
Digital Input Capacitance MSBINV and PGA Only 1.5 pF
High Level Output Voltage OVDD = 4.75V IO = –10µA 4.74 V
Low Level Output Voltage OVDD = 4.75V IO = 160µA 0.05 V
Output Source Current V
Output Sink Current V
OUT
OUT
DD
= 0V –50 mA
= 5V 50 mA
The ● indicates specifications which apply over the full
● ±10 µA
IO = –200µA ● 4 4.74 V
IO = 1.6mA ● 0.1 0.4 V
WU
POWER REQUIRE E TS
range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
I
DD
P
OV
DD
DIS
DD
Positive Supply Voltage 4.75 5.25 V
Positive Supply Current ● 290 338 mA
Power Dissipation ● 1.45 1.69 W
Digital Output Supply Voltage 0.5 V
The ● indicates specifications which apply over the full operating temperature
DD
V
UW
TI I G CHARACTERISTICS
range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
0
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
ENC Period (Note 9) ● 12.5 2000 ns
ENC High (Note 8) ● 6 1000 ns
ENC Low (Note 8) ● 6 1000 ns
Aperture Delay (Note 8) 0 ns
ENC to CLKOUT Falling CL = 10pF (Note 8) ● 1 2.4 4 ns
ENC to CLKOUT Rising CL = 10pF (Note 8) t1 + t
For 80Msps 50% Duty Cycle CL = 10pF (Note 8) ● 7.25 8.65 10.25 ns
ENC to DATA Delay CL = 10pF (Note 8) ● 2 4.9 7.2 ns
ENC to DATA Delay (Hold Time) (Note 8) ● 1.4 3.4 4.7 ns
ENC to DATA Delay (Setup Time) CL = 10pF (Note 8) t0 – t
For 80Msps 50% Duty Cycle CL = 10pF (Note 8) ● 5.3 7.6 10.5 ns
CLKOUT to DATA Delay (Hold Time), (Note 8) ● 6ns
80Msps 50% Duty Cycle
CLKOUT to DATA Delay (Setup Time), CL = 10pF (Note 8) ● 2.1 ns
80Msps 50% Duty Cycle
Data Latency 5 cycles
The ● indicates specifications which apply over the full operating temperature
4
6
ns
ns
4
1749f
ELECTRICAL CHARACTERISTICS
LTC1749
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All voltage values are with respect to GND (unless otherwise
noted).
Note 3: When these pin voltages are taken below GND or above V
DD
, they
will be clamped by internal diodes. This product can handle input currents
of greater than 100mA below GND or above V
without latchup.
DD
Note 4: When these pin voltages are taken below GND, they will be
clamped by internal diodes. This product can handle input currents of
>100mA below GND without latchup. These pins are not clamped to VDD.
Note 5: V
DD
= 5V, f
sine wave, input range = ±1.125V differential, unless otherwise specified.
Note 6: Integral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual endpoints of the transfer curve.
The deviation is measured from the center of the quantization band.
Note 7: Bipolar offset is the offset voltage measured from –0.5 LSB
when the output code flickers between 0000 0000 0000 and
1111 1111 1111.
Note 8: Guaranteed by design, not subject to test.
Note 9: Recommended operating conditions.
UW
TYPICAL PERFOR A CE CHARACTERISTICS
INL
1.0
0.8
0.6
0.4
0.2
0
–0.2
ERROR (LSB)
–0.4
–0.6
–0.8
–1.0
0
1024
2048
OUTPUT CODE
3072
4096
1749 G01
DNL
1.0
0.8
0.6
0.4
0.2
0
–0.2
ERROR (LSB)
–0.4
–0.6
–0.8
–1.0
0
1024
2048
OUTPUT CODE
3072
1749 G02
= 80MHz, differential ENC/ENC = 2V
SAMPLE
8192 Point FFT, fIN = 15MHz,
–1dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
4096
–120
5
0
10
20
15
FREQUENCY (MHz)
25
P-P
30
80MHz
35
1749 G03
40
8192 Point FFT, fIN = 15MHz,
–10dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
8192 Point FFT, fIN = 15MHz,
–20dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
25
30
35
1749 G04
40
–120
20
5
0
10
15
FREQUENCY (MHz)
25
30
35
1749 G05
40
8192 Point FFT, fIN = 30.2MHz,
–1dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
30
35
1749 G06
40
1749f
5
LTC1749
UW
TYPICAL PERFOR A CE CHARACTERISTICS
8192 Point FFT, fIN = 30.2MHz,
–10dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
8192 Point FFT, fIN = 70.03MHz,
–10dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
8192 Point FFT, fIN = 30.2MHz,
–20dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
35
1749 G07
40
30
–120
5
0
10
20
15
FREQUENCY (MHz)
25
35
1749 G08
40
30
8192 Point FFT, fIN = 70.03MHz,
–20dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
35
1749 G10
40
30
–120
5
0
10
20
15
FREQUENCY (MHz)
25
35
1749 G11
40
30
8192 Point FFT, fIN = 70.03MHz,
–1dB, PGA = 0
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
8192 Point FFT, fIN = 140.2MHz,
–1dB, PGA = 1
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
35
1749 G09
35
1749 G12
40
40
30
30
8192 Point FFT, fIN = 140.2MHz,
–10dB, PGA = 1
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
6
8192 Point FFT, fIN = 140.2MHz,
–20dB, PGA = 1
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
25
30
35
1749 G13
40
–120
20
5
0
10
15
FREQUENCY (MHz)
25
30
35
1749 G14
40
8192 Point FFT, fIN = 250.2MHz,
–1dB, PGA = 1
0
–10
–20
–30
–40
–50
–60
–70
–80
AMPLITUDE (dBFS)
–90
–100
–110
–120
5
0
10
20
15
FREQUENCY (MHz)
25
35
1749 G15
40
1749f
30
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