INPUT FREQUENCY (MHZ)
0
SNR (dBFS)
200
2249 TAO1b
50
100
150
75
74
73
72
71
70
查询LTC2246供应商
FEATURES
■
Sample Rate: 65Msps/40Msps/25Msps
■
Single 3V Supply (2.7V to 3.4V)
■
Low Power: 205mW/120mW/75mW
■
74dB SNR up to 70MHz Input
■
80dB SFDR up to 140MHz Input
■
No Missing Codes
■
Flexible Input: 1V
■
575MHz Full Power Bandwidth S/H
■
Clock Duty Cycle Stabilizer
■
Shutdown and Nap Modes
■
Pin Compatible Family
P-P
to 2V
P-P
Range
80Msps: LTC2229 (12-Bit), LTC2249 (14-Bit)
65Msps: LTC2228 (12-Bit), LTC2248 (14-Bit)
40Msps: LTC2227 (12-Bit), LTC2247 (14-Bit)
25Msps: LTC2226 (12-Bit), LTC2246 (14-Bit)
10Msps: LTC2225 (12-Bit), LTC2245 (14-Bit)
■
32-Pin (5mm × 5mm) QFN Package
U
APPLICATIO S
LTC2248/LTC2247/LTC2246
14-Bit, 65/40/25Msps
Low Power 3V ADCs
U
DESCRIPTIO
The LTC®2248/LTC2247/LTC2246 are 14-bit 65Msps/
40Msps/25Msps, low power 3V A/D converters designed
for digitizing high frequency, wide dynamic range signals.
The LTC2248/LTC2247/LTC2246 are perfect for demanding imaging and communications applications with AC
performance that includes 74dB SNR and 80dB SFDR for
signals well beyond the Nyquist frequency.
DC specs include ±1LSB INL (typ), ±0.5LSB DNL (typ) and
no missing codes over temperature. The transition noise
is a low 1LSB
A single 3V supply allows low power operation. A separate
output supply allows the outputs to drive 0.5V to 3.3V
logic.
A single-ended CLK input controls converter operation. 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.
RMS
.
■
Wireless and Wired Broadband Communication
■
Imaging Systems
■
Ultrasound
■
Spectral Analysis
■
Portable Instrumentation
U
TYPICAL APPLICATIO
REFH
REFL
ANALOG
INPUT
FLEXIBLE
REFERENCE
+
INPUT
S/H
–
CLOCK/DUTY
CYCLE
CONTROL
CLK
14-BIT
PIPELINED
ADC CORE
CORRECTION
LOGIC
OUTPUT
DRIVERS
2249 TA01a
OV
DD
D13
•
•
•
D0
OGND
LTC2248: SNR vs Input Frequency,
–1dB, 2V Range, 65Msps
224876f
1
LTC2248/LTC2247/LTC2246
WW
W
U
ABSOLUTE AXI U RATI GS
OVDD = VDD (Notes 1, 2)
Supply Voltage (VDD) ................................................. 4V
Digital Output Ground Voltage (OGND) ....... –0.3V to 1V
Analog Input Voltage (Note 3) ..... –0.3V to (V
Digital Input Voltage .................... –0.3V to (V
Digital Output Voltage ................– 0.3V to (OV
Power Dissipation............................................ 1500mW
Operating Temperature Range
LTC2248C, LTC2247C, LTC2246C........... 0°C to 70°C
LTC2248I, LTC2247I, LTC2246I .......... –40°C to 85°C
Storage Temperature Range ..................–65°C to 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
+ 0.3V)
DD
+ 0.3V)
DD
+ 0.3V)
DD
UUW
PACKAGE/ORDER I FOR ATIO
TOP VIEW
VDDVCMSENSE
MODEOFD13
D12
32 31 30 29 28 27 26 25
+
1AIN
–
AIN
2
REFH
3
REFH
4
REFL
5
REFL
6
V
7
DD
GND
8
9 10 11 12
32-LEAD (5mm × 5mm) PLASTIC QFN
T
JMAX
EXPOSED PAD IS GND (PIN 33)
MUST BE SOLDERED TO PCB
33
OED0D1D2D3
CLK
SHDN
UH PACKAGE
= 125°C, θJA = 34°C/W
13 14 15 16
D11
D4
D10
24
D9
23
D8
22
OV
21
DD
OGND
20
D7
19
D6
18
D5
17
Consult LTC Marketing for parts specified with wider operating temperature ranges.
*The temperature grade is identified by a label on the shipping container.
ORDER PART
NUMBER
LTC2248CUH
LTC2248IUH
LTC2247CUH
LTC2247IUH
LTC2246CUH
LTC2246IUH
QFN PART*
MARKING
2248
2247
2246
U
CO VERTER CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C. (Note 4)
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
Resolution ● 14 14 14 Bits
(No Missing Codes)
Integral Differential Analog Input ● –4 ±14–4±14–4±1 4 LSB
Linearity Error (Note 5)
Differential Differential Analog Input ● –1 ±0.5 1 –1 ±0.5 1 –1 ±0.5 1 LSB
Linearity Error
Offset Error (Note 6) ● –12 ±212–12±212–12±212 mV
Gain Error External Reference ● –2.5 ±0.5 2.5 – 2.5 ±0.5 2.5 – 2.5 ±0.5 2.5 %FS
Offset Drift ±10 ±10 ±10 µV/°C
Full-Scale Drift Internal Reference ±30 ±30 ±30 ppm/°C
External Reference ±15 ±15 ±15 ppm/°C
Transition Noise SENSE = 1V 1 1 1 LSB
The ● denotes the specifications which apply over the full operating
LTC2248 LTC2247 LTC2246
RMS
2
224876f
LTC2248/LTC2247/LTC2246
UU
A ALOG I PUT
specifications are at TA = 25°C. (Note 4)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
V
IN,CM
I
IN
I
SENSE
I
MODE
t
AP
t
JITTER
CMRR Analog Input Common Mode Rejection Ratio 80 dB
U
Analog Input Range (A
Analog Input Common Mode Differential Input (Note 7) ● 1 1.5 1.9 V
Analog Input Leakage Current 0V < A
SENSE Input Leakage 0V < SENSE < 1V ● –3 3 µA
MODE Pin Leakage ● –3 3 µA
Sample-and-Hold Acquisition Delay Time 0 ns
Sample-and-Hold Acquisition Delay Time Jitter 0.2 ps
Full Power Bandwidth Figure 8 Test Circuit 575 MHz
W
DY A IC ACCURACY
otherwise specifications are at TA = 25°C. AIN = –1dBFS. (Note 4)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
SNR Signal-to-Noise Ratio 5MHz Input 74.3 74.4 74.5 dB
SFDR 5MHz Input 90 90 90 dB
SFDR 5MHz Input 95 95 95 dB
S/(N+D) 5MHz Input 74.3 74.4 74.5 dB
I
MD
Spurious Free
Dynamic Range
2nd or 3rd
Harmonic
Spurious Free
Dynamic Range
4th Harmonic
or Higher
Signal-to-Noise
Plus Distortion
Ratio
Intermodulation f
Distortion f
The ● denotes the specifications which apply over the full operating temperature range, otherwise
+
–
–A
IN
) 2.7V < V
IN
< 3.4V (Note 7) ● 1V to 2V V
DD
+
–
, A
< V
IN
IN
DD
● –1 1 µA
RMS
The ● denotes the specifications which apply over the full operating temperature range,
LTC2248 LTC2247 LTC2246
12.5MHz Input ● 72.9 74.2 dB
20MHz Input ● 72.9 74.4 dB
30MHz Input ● 72.5 74.3 dB
70MHz Input 74.3 73.9 73.4 dB
140MHz Input 73.9 73.3 73 dB
12.5MHz Input ● 76 90 dB
20MHz Input ● 76 90 dB
30MHz Input ● 76 90 dB
70MHz Input 85 85 85 dB
140MHz Input 80 80 80 dB
12.5MHz Input ● 84 95 dB
20MHz Input ● 84 95 dB
30MHz Input ● 84 95 dB
70MHz Input 95 95 95 dB
140MHz Input 90 90 90 dB
12.5MHz Input ● 72.2 74.2 dB
20MHz Input ● 72.2 74.3 dB
30MHz Input ● 72 74.2 dB
70MHz Input 74.1 73.6 73.4 dB
140MHz Input 71.9 71.9 71.8 dB
= 28.2MHz 90 90 90 dB
IN1
= 26.8MHz
IN2
224876f
3
LTC2248/LTC2247/LTC2246
UU U
I TER AL REFERE CE CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
VCM Output Voltage I
VCM Output Tempco ±30 ppm/C
VCM Line Regulation 2.7V < VDD < 3.4V 3 mV/V
VCM Output Resistance –1mA < I
= 0 1.475 1.500 1.525 V
OUT
(Note 4)
< 1mA 4 Ω
OUT
UU
DIGITAL I PUTS A D DIGITAL OUTPUTS
full operating temperature range, otherwise specifications are at T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
LOGIC INPUTS (CLK, OE, SHDN)
V
IH
V
IL
I
IN
C
IN
LOGIC OUTPUTS
OVDD = 3V
C
OZ
I
SOURCE
I
SINK
V
OH
V
OL
OV
= 2.5V
DD
V
OH
V
OL
OVDD = 1.8V
V
OH
V
OL
High Level Input Voltage VDD = 3V ● 2V
Low Level Input Voltage VDD = 3V ● 0.8 V
Input Current VIN = 0V to V
Input Capacitance (Note 7) 3 pF
Hi-Z Output Capacitance OE = High (Note 7) 3 pF
Output Source Current V
Output Sink Current V
High Level Output Voltage IO = –10µA 2.995 V
Low Level Output Voltage IO = 10µA 0.005 V
High Level Output Voltage IO = –200µA 2.49 V
Low Level Output Voltage IO = 1.6mA 0.09 V
High Level Output Voltage IO = –200µA 1.79 V
Low Level Output Voltage IO = 1.6mA 0.09 V
= 25°C. (Note 4)
A
= 0V 50 mA
OUT
= 3V 50 mA
OUT
I
= –200µA ● 2.7 2.99 V
O
I
= 1.6mA ● 0.09 0.4 V
O
The ● denotes the specifications which apply over the
DD
● –10 10 µA
WU
POWER REQUIRE E TS
range, otherwise specifications are at TA = 25°C. (Note 8)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
V
DD
OV
IV
P
DISS
P
SHDN
P
NAP
DD
DD
Analog Supply (Note 9) ● 2.7 3 3.4 2.7 3 3.4 2.7 3 3.4 V
Voltage
Output Supply (Note 9) ● 0.5 3 3.6 0.5 3 3.6 0.5 3 3.6 V
Voltage
Supply Current ● 68.3 80 40 48 25 30 mA
Power Dissipation ● 205 240 120 144 75 90 mW
Shutdown Power SHDN = H, 2 2 2 mW
OE = H, No CLK
Nap Mode Power SHDN = H, 15 15 15 mW
OE = L, No CLK
The ● denotes the specifications which apply over the full operating temperature
LTC2248 LTC2247 LTC2246
4
224876f
LTC2248/LTC2247/LTC2246
UW
TI I G CHARACTERISTICS
range, otherwise specifications are at T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
f
s
t
L
t
H
t
AP
t
D
Pipeline 6 6 6 Cycles
Latency
Sampling Frequency (Note 9) ● 165140125MHz
CLK Low Time Duty Cycle Stabilizer Off ● 7.3 7.7 500 11.8 12.5 500 18.9 20 500 ns
Duty Cycle Stabilizer On
(Note 7)
CLK High Time Duty Cycle Stabilizer Off ● 7.3 7.7 500 11.8 12.5 500 18.9 20 500 ns
Duty Cycle Stabilizer On
(Note 7)
Sample-and-Hold 0 0 0 ns
Aperture Delay
CLK to DATA delay CL = 5pF (Note 7) ● 1.4 2.7 5.4 1.4 2.7 5.4 1.4 2.7 5.4 ns
Data Access Time CL = 5pF (Note 7) ● 4.3 10 4.3 10 4.3 10 ns
After OE↓
BUS Relinquish Time (Note 7) ● 3.3 8.5 3.3 8.5 3.3 8.5 ns
= 25°C. (Note 4)
A
The ● denotes the specifications which apply over the full operating temperature
LTC2248 LTC2247 LTC2246
● 5 7.7 500 5 12.5 500 5 20 500 ns
● 5 7.7 500 5 12.5 500 5 20 500 ns
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 ground with GND and OGND
wired together (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 VDD without latchup.
Note 4: VDD = 3V, f
25MHz (LTC2246), input range = 2V
= 65MHz (LTC2248), 40MHz (LTC2247), or
SAMPLE
with differential drive, unless
P-P
otherwise noted.
Note 5: 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 6: Offset error is the offset voltage measured from –0.5 LSB when
the output code flickers between 00 0000 0000 0000 and
11 1111 1111 1111.
Note 7: Guaranteed by design, not subject to test.
Note 8: V
= 3V, f
DD
25MHz (LTC2246), input range = 1V
Note 9: Recommended operating conditions.
UW
TYPICAL PERFOR A CE CHARACTERISTICS
LTC2248: Typical INL,
2V Range, 65Msps
2.0
1.5
1.0
0.5
0
–0.5
INL ERROR (LSB)
–1.0
–1.5
–2.0
0
4096 8192 16384
CODE
12288
2248 G01
1.00
0.75
0.50
0.25
0
–0.25
DNL ERROR (LSB)
–0.50
–0.75
–1.00
= 65MHz (LTC2248), 40MHz (LTC2247), or
SAMPLE
P-P
LTC2248: Typical DNL,
2V Range, 65Msps
4096 8192 16384
0
CODE
with differential drive.
12288
2248 G02
224876f
5
LTC2248/LTC2247/LTC2246
UW
TYPICAL PERFOR A CE CHARACTERISTICS
LTC2248: 8192 Point FFT,
fIN = 5MHz, –1dB, 2V Range,
65Msps
0
–10
–20
–30
–40
–50
–60
–70
AMPLITUDE (dB)
–80
–90
–100
–110
–120
0
LTC2248: 8192 Point FFT,
fIN = 70MHz, –1dB, 2V Range,
65Msps
0
–10
–20
–30
–40
–50
–60
–70
AMPLITUDE (dB)
–80
–90
–100
–110
–120
0
510152025
FREQUENCY (MHz)
510152025
FREQUENCY (MHz)
LTC2248: 8192 Point FFT,
fIN = 140MHz, –1dB, 2V Range,
65Msps
0
–10
–20
–30
–40
–50
–60
–70
AMPLITUDE (dB)
–80
–90
–100
–110
30
2248 G05
–120
0
30
2248 G03
510152025
FREQUENCY (MHz)
LTC2248: 8192 Point FFT,
fIN = 30MHz, –1dB, 2V Range,
65Msps
0
–10
–20
–30
–40
–50
–60
–70
AMPLITUDE (dB)
–80
–90
–100
–110
–120
0
510152025
FREQUENCY (MHz)
LTC2248: 8192 Point 2-Tone FFT,
fIN = 28.2MHz and 26.8MHz,
–1dB, 2V Range, 65Msps
0
–10
–20
–30
–40
–50
–60
–70
AMPLITUDE (dB)
–80
–90
–100
–110
30
2248 G06
–120
0
30
2248 G04
510152025
FREQUENCY (MHz)
30
2248 G06a
LTC2248: Grounded Input
Histogram, 65Msps
25000
21824
20000
15000
COUNT
10000
5000
2116
172
0
8196 8197 8198 8199 8200 8201 8202 8203
20412
10224
CODE
6
9042
1596
121
2248 G08
LTC2248: SNR vs Input Frequency,
–1dB, 2V Range, 65Msps
75
74
73
72
SNR (dBFS)
71
70
0
50
INPUT FREQUENCY (MHz)
100
150
2248 G09
200
LTC2248: SFDR vs Input Frequency,
–1dB, 2V Range, 65Msps
100
95
90
85
80
SFDR (dBFS)
75
70
65
0
50 100 200
INPUT FREQUENCY (MHz)
150
2248 G10
224876f
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