LTC2251/LTC2250
10-Bit, 125/105Msps
Low Noise 3V ADCs
FEATURES
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DESCRIPTIO
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Sample Rate: 125Msps/105Msps
Single 3V Supply (2.85V to 3.4V)
Low Power: 395mW/320mW
61.6dB SNR
85dB SFDR
No Missing Codes
Flexible Input: 1V
P-P
to 2V
P-P
Range
640MHz Full Power Bandwidth S/H
Clock Duty Cycle Stabilizer
Shutdown and Nap Modes
Pin Compatible Family:
125Msps: LTC2251 (10-Bit), LTC2253 (12-Bit)
105Msps: LTC2250 (10-Bit), LTC2252 (12-Bit)
80Msps: LTC2239 (10-Bit), LTC2229 (12-Bit)
65Msps: LTC2238 (10-Bit), LTC2228 (12-Bit)
40Msps: LTC2237 (10-Bit), LTC2227 (12-Bit)
25Msps: LTC2236 (10-Bit), LTC2226 (12-Bit)
32-Pin (5mm
×
5mm) QFN Package
The LTC
®
2251/LTC2250 are 10-bit 125Msps/105Msps,
low noise 3V A/D converters designed for digitizing high
frequency, wide dynamic range signals. The LTC2251/
LTC2250 are perfect for demanding imaging and commu-
nications applications with AC performance that includes
61.6dB SNR and 85dB SFDR for signals at the Nyquist
frequency.
DC specs include
±0.1LSB
INL (typ),
±0.05LSB
DNL (typ)
and
±0.6LSB
INL,
±0.6LSB
DNL over temperature. The
transition noise is a low 0.08LSB
RMS
.
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 perfor-
mance 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.
APPLICATIO S
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Wireless and Wired Broadband Communication
Imaging Systems
Ultrasound
Spectral Analysis
Portable Instrumentation
TYPICAL APPLICATIO
REFH
REFL
FLEXIBLE
REFERENCE
OV
DD
+
ANALOG
INPUT
INPUT
S/H
SNR (dBFS)
–
10-BIT
PIPELINED
ADC CORE
CORRECTION
LOGIC
OUTPUT
DRIVERS
D9
•
•
•
D0
OGND
CLOCK/DUTY
CYCLE
CONTROL
22510 TA01
CLK
22510fa
U
LTC2251: SNR vs Input Frequency,
–1dB, 2V Range, 125Msps
65
64
63
62
61
60
59
58
57
56
55
0
50
100 150 200 250 300 350
22510 G09
INPUT FREQUENCY (MHz)
U
U
1
LTC2251/LTC2250
ABSOLUTE
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
OV
DD
= V
DD
(Notes 1, 2)
Supply Voltage (V
DD
) ................................................. 4V
Digital Output Ground Voltage (OGND) ....... –0.3V to 1V
Analog Input Voltage (Note 3) ..... –0.3V to (V
DD
+ 0.3V)
Digital Input Voltage .................... –0.3V to (V
DD
+ 0.3V)
Digital Output Voltage ................ –0.3V to (OV
DD
+ 0.3V)
Power Dissipation ............................................ 1500mW
Operating Temperature Range
LTC2251C, LTC2250C ............................. 0°C to 70°C
LTC2251I, LTC2250I ...........................–40°C to 85°C
Storage Temperature Range ..................–65°C to 125°C
SENSE
MODE
V
CM
V
DD
D9
D8
D7
ORDER PART
NUMBER
24 D6
23 D5
22 D4
OF
32 31 30 29 28 27 26 25
AIN
+
1
AIN
–
2
REFH 3
REFH 4
REFL 5
REFL 6
V
DD
7
GND 8
9 10 11 12 13 14 15 16
33
21 OV
DD
20 OGND
19 D3
18 D2
17 D1
LTC2251CUH
LTC2251IUH
LTC2250CUH
LTC2250IUH
QFN PART*
MARKING
2251
2250
SHDN
OE
NC
NC
NC
UH PACKAGE
32-LEAD (5mm
×
5mm) PLASTIC QFN
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.
CO VERTER CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Gain Error
Offset Drift
Full-Scale Drift
Transition Noise
Internal Reference
External Reference
SENSE = 1V
CONDITIONS
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 4)
LTC2251
MIN
TYP
MAX
●
CLK
T
JMAX
= 125°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 33) IS GND
MUST BE SOLDERED TO PCB
NC
D0
LTC2250
MIN
TYP
MAX
10
–0.6
–0.6
–12
–2.5
±0.1
±0.05
±2
±0.5
±10
±30
±5
0.08
0.6
0.6
12
2.5
UNITS
Bits
LSB
LSB
mV
%FS
µV/°C
ppm/°C
ppm/°C
LSB
RMS
10
–0.6
–0.6
–12
–2.5
±0.1
±0.05
±2
±0.5
±10
±30
±5
0.08
0.6
0.6
12
2.5
Differential Analog Input
(Note 5)
Differential Analog Input
(Note 6)
External Reference
●
●
●
●
22510fa
2
U
W
U
U
W W
W
U
LTC2251/LTC2250
A ALOG I PUT
SYMBOL
V
IN
V
IN,CM
I
IN
I
SENSE
I
MODE
t
AP
t
JITTER
CMRR
PARAMETER
The
●
denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at T
A
= 25°C. (Note 4)
CONDITIONS
2.85V < V
DD
< 3.4V (Note 7)
Differential Input (Note 7)
0V < A
IN+
, A
IN–
< V
DD
0V < SENSE < 1V
●
●
●
●
●
Analog Input Range (A
IN+
–A
IN–
)
Analog Input Common Mode
Analog Input Leakage Current
SENSE Input Leakage
MODE Pin Leakage
Sample-and-Hold Acquisition Delay Time
Sample-and-Hold Acquisition Delay Time Jitter
Analog Input Common Mode Rejection Ratio
Full Power Bandwidth
DY A IC ACCURACY
SYMBOL
SNR
PARAMETER
Signal-to-Noise Ratio
The
●
denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. A
IN
= –1dBFS. (Note 4)
CONDITIONS
5MHz Input
30MHz Input
70MHz Input
140MHz Input
SFDR
Spurious Free
Dynamic Range
2nd or 3rd
Harmonic
Spurious Free
Dynamic Range
4th Harmonic
or Higher
Signal-to-Noise
Plus Distortion
Ratio
5MHz Input
30MHz Input
70MHz Input
140MHz Input
SFDR
5MHz Input
30MHz Input
70MHz Input
140MHz Input
S/(N+D)
5MHz Input
30MHz Input
70MHz Input
140MHz Input
IMD
Intermodulation
Distortion
f
IN1
= 28.2MHz,
f
IN2
= 26.8MHz
●
●
●
●
U
W U
U
MIN
1
–1
–3
–3
TYP
1.5
MAX
1.9
1
3
3
UNITS
V
V
µA
µA
µA
ns
ps
RMS
dB
MHz
±0.5V
to
±1V
0
0.2
80
Figure 8 Test Circuit
640
MIN
LTC2251
TYP
MAX
61.6
61.6
LTC2250
MIN
TYP
MAX
61.6
61.6
60
61.5
61.4
85
85
69
83
77
85
85
75
85
85
61.6
61.6
60
61.5
61.3
80
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
60
61.5
61.4
85
85
69
82
77
85
85
75
85
85
61.5
61.5
60
61.4
61.2
80
22510fa
3
LTC2251/LTC2250
I TER AL REFERE CE CHARACTERISTICS
PARAMETER
V
CM
Output Voltage
V
CM
Output Tempco
V
CM
Line Regulation
V
CM
Output Resistance
CONDITIONS
I
OUT
= 0
DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL
V
IH
V
IL
I
IN
C
IN
LOGIC OUTPUTS
OV
DD
= 3V
C
OZ
I
SOURCE
I
SINK
V
OH
V
OL
OV
DD
= 2.5V
V
OH
V
OL
OV
DD
= 1.8V
V
OH
V
OL
High Level Output Voltage
Low Level Output Voltage
I
O
= –200µA
I
O
= 1.6mA
High Level Output Voltage
Low Level Output Voltage
I
O
= –200µA
I
O
= 1.6mA
Hi-Z Output Capacitance
Output Source Current
Output Sink Current
High Level Output Voltage
Low Level Output Voltage
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Input Current
Input Capacitance
CONDITIONS
V
DD
= 3V
V
DD
= 3V
LOGIC INPUTS (CLK, OE, SHDN)
The
●
denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 4)
MIN
●
●
●
4
U
U
U
U
U
(Note 4)
MIN
1.475
TYP
1.500
±25
3
4
MAX
1.525
UNITS
V
ppm/°C
mV/V
Ω
2.85V < V
DD
< 3.4V
–1mA < I
OUT
< 1mA
TYP
MAX
UNITS
V
2
0.8
–10
3
10
V
µA
pF
V
IN
= 0V to V
DD
(Note 7)
OE = High (Note 7)
V
OUT
= 0V
V
OUT
= 3V
I
O
= –10µA
I
O
= –200µA
I
O
= 10µA
I
O
= 1.6mA
●
●
3
50
50
2.7
2.995
2.99
0.005
0.09
2.49
0.09
1.79
0.09
0.4
pF
mA
mA
V
V
V
V
V
V
V
V
22510fa
LTC2251/LTC2250
POWER REQUIRE E TS
SYMBOL
V
DD
OV
DD
I
VDD
P
DISS
P
SHDN
P
NAP
PARAMETER
Analog Supply
Voltage
Output Supply
Voltage
Supply Current
Power Dissipation
Shutdown Power
Nap Mode Power
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 8)
CONDITIONS
(Note 9)
(Note 9)
●
●
●
●
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 4)
SYMBOL
f
s
t
L
PARAMETER
Sampling Frequency
CLK Low Time
CONDITIONS
(Note 9)
Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
(Note 7)
Duty Cycle Stabilizer Off
Duty Cycle Stabilizer On
(Note 7)
●
●
●
●
●
TI I G CHARACTERISTICS
t
H
CLK High Time
t
AP
t
D
Sample-and-Hold
Aperture Delay
CLK to DATA Delay
Data Access Time
After OE↓
BUS Relinquish Time
C
L
= 5pF (Note 7)
C
L
= 5pF (Note 7)
(Note 7)
●
●
●
Pipeline
Latency
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 V
DD
, they
will be clamped by internal diodes. This product can handle input currents
of greater than 100mA below GND or above V
DD
without latchup.
Note 4:
V
DD
= 3V, f
SAMPLE
= 125MHz (LTC2251) or 105MHz (LTC2250),
input range = 2V
P-P
with differential drive, clock duty cycle stabilizer on,
unless otherwise noted.
U W
LTC2251
MIN
TYP
MAX
2.85
0.5
3
3
132
395
2
15
3.4
3.6
156
468
LTC2250
MIN
TYP
MAX
2.85
0.5
3
3
107
320
2
15
3.4
3.6
126
378
UNITS
V
V
mA
mW
mW
mW
SHDN = H,
OE = H, No CLK
SHDN = H,
OE = L, No CLK
UW
MIN
1
3.8
3
3.8
3
LTC2251
TYP
MAX
125
4
4
4
4
0
500
500
500
500
MIN
1
4.5
3
4.5
3
LTC2250
TYP
MAX
105
4.76
4.76
4.76
4.76
0
500
500
500
500
UNITS
MHz
ns
ns
ns
ns
ns
1.4
2.7
4.3
3.3
5
5.4
10
8.5
1.4
2.7
4.3
3.3
5
5.4
10
8.5
ns
ns
ns
Cycles
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 and 11 1111 1111.
Note 7:
Guaranteed by design, not subject to test.
Note 8:
V
DD
= 3V, f
SAMPLE
= 125MHz (LTC2251) or 105MHz (LTC2250),
input range = 1V
P-P
with differential drive.
Note 9:
Recommended operating conditions.
22510fa
5
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