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LTC1746
1746f
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
BLOCK DIAGRA
W
Low Power,14-Bit, 25Msps ADC
Sample Rate: 25Msps
77.5dB SNR and 91dB SFDR (3.2V Range)
74dB SNR and 96dB SFDR (2V Range)
No Missing Codes
Single 5V Supply
Low Power Dissipation: 390mW
Selectable Input Ranges: ±1V or ±1.6V
240MHz Full Power Bandwidth S/H
Pin Compatible Family
25 Msps: LTC1746 (14-Bit), LTC1745 (12-Bit)
50 Msps: LTC1744 (14-Bit), LTC1743 (12-Bit)
65 Msps: LTC1742 (14-Bit), LTC1741 (12-Bit)
80 Msps: LTC1748 (14-Bit), LTC1747 (12-Bit)
Telecommunications
Medical Imaging
Receivers
Base Stations
Spectrum Analysis
Imaging Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
The LTC
®
1746 is a 25Msps, sampling 14-bit A/D con-
verter designed for digitizing high frequency, wide dy-
namic range signals. Pin selectable input ranges of ±1V
and ±1.6V along with a resistor programmable mode
allow the LTC1746’s input range to be optimized for a wide
variety of applications.
The LTC1746 is perfect for demanding communications
applications with AC performance that includes 77.5dB
SNR and 91dB spurious free dynamic range. Ultralow jitter
of 0.3ps
RMS
allows undersampling with excellent noise
performance. DC specs include ±3LSB INL maximum and
no missing codes over temperature.
The digital interface is compatible with 5V, 3V and 2V logic
systems. The ENC and ENC inputs may be driven differen-
tially 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 digital
output power supply can be operated from 0.5V to 5V,
making it easy to connect directly to low voltage DSPs
or FIFOs.
The TSSOP package with a flow-through pinout simplifies
the board layout.
25Msps, 14-Bit ADC with a ±1V Differential Input Range
14-BIT
PIPELINED ADC
14
S/H
AMP
±1V
DIFFERENTIAL
ANALOG INPUT
A
IN
+
A
IN
SENSE
V
CM
4.7µF
DIFF AMP
REFLA REFHB
GND
1746 BD
ENC
4.7µF
1µF1µF
0.1µF 0.1µF
REFHAREFLB
BUFFER
RANGE
SELECT
2.35V
REF
OUTPUT
LATCHES
CONTROL LOGIC
OV
DD
V
DD
OGND
0.5V TO 5V
5V
0.1µF
1µF 1µF 1µF
D13
D0
CLKOUT
OF
ENC
DIFFERENTIAL
ENCODE INPUT
OEMSBINV
0.1µF
2
LTC1746
1746f
PARAMETER CONDITIONS MIN TYP MAX UNITS
Resolution (No Missing Codes) 14 Bits
Integral Linearity Error (Note 6) –3 ±1 3 LSB
Differential Linearity Error –1 ±0.5 1 LSB
Offset Error (Note 7) –30 ±530 mV
Gain Error External Reference (SENSE = 1.6V) 2.5 ±1 2.5 %FS
Full-Scale Tempco I
OUT(REF)
= 0 ±40 ppm/°C
ORDER PART
NUMBER
OV
DD
= V
DD
(Notes 1, 2)
Supply Voltage (V
DD
)............................................. 5.5V
Analog Input Voltage (Note 3) ....0.3V to (V
DD
+ 0.3V)
Digital Input Voltage (Note 4) .....0.3V to (V
DD
+ 0.3V)
Digital Output Voltage.................0.3V to (V
DD
+ 0.3V)
OGND Voltage..............................................0.3V to 1V
Power Dissipation............................................ 2000mW
Operating Temperature Range
LTC1746C ............................................... 0°C to 70°C
LTC1746I............................................ – 40°C to 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
LTC1746CFW
LTC1746IFW
T
JMAX
= 150°C, θ
JA
= 35°C/W
The indicates specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 5)
ABSOLUTE MAXIMUM RATINGS
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WW
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PACKAGE/ORDER INFORMATION
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25
SENSE
V
CM
GND
A
IN
+
A
IN
GND
V
DD
V
DD
GND
REFLB
REFHA
GND
GND
REFLA
REFHB
GND
V
DD
V
DD
GND
V
DD
GND
MSBINV
ENC
ENC
OF
OGND
D13
D12
D11
OV
DD
D10
D9
D8
D7
OGND
GND
GND
D6
D5
D4
OV
DD
D3
D2
D1
D0
OGND
CLKOUT
OE
CO VERTER CHARACTERISTICS
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SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Analog Input Range (Note 8) 4.75V V
DD
5.25V ±1 to ±1.6 V
I
IN
Analog Input Leakage Current –1 1 µA
C
IN
Analog Input Capacitance Sample Mode ENC < ENC 8 pF
Hold Mode ENC > ENC 4 pF
t
ACQ
Sample-and-Hold Acquisition Time 15 18 ns
t
AP
Sample-and-Hold Acquisition Delay Time 0 ns
t
JITTER
Sample-and-Hold Acquisition Delay Time Jitter 0.3 ps
RMS
CMRR Analog Input Common Mode Rejection Ratio 1.0V < (A
IN
= A
IN
+
) < 3.5V 80 dB
The indicates specifications which apply over the full operating temperature range, otherwise
specifications are at T
A
= 25°C. (Note 5)
A ALOG I PUT
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Consult LTC Marketing for parts specified with wider operating temperature ranges.
3
LTC1746
1746f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
SNR Signal-to-Noise Ratio 5MHz Input Signal (2V Range) 74 dBFS
5MHz Input Signal (3.2V Range)
75.5 77.5 dBFS
30MHz Input Signal (2V Range) 73.5 dBFS
30MHz Input Signal (3.2V Range) 76.5 dBFS
70MHz Input Signal (2V Range) 72.5 dBFS
70MHz Input Signal (3.2V Range) 75 dBFS
SFDR Spurious Free Dynamic Range 5MHz Input Signal (2V Range) 96 dB
5MHz Input Signal (3.2V Range)
80 91 dB
30MHz Input Signal (2V Range) 95 dB
30MHz Input Signal (3.2V Range) 86.5 dB
70MHz Input Signal (2V Range) 79 dB
70MHz Input Signal (3.2V Range) 71 dB
S/(N + D) Signal-to-(Noise + Distortion) Ratio 5MHz Input Signal (2V Range) 74 dBFS
5MHz Input Signal (3.2V Range)
75 77.5 dBFS
30MHz Input Signal (2V Range) 73.5 dBFS
30MHz Input Signal (3.2V Range) 76.5 dBFS
70MHz Input Signal (2V Range) 71.5 dBFS
70MHz Input Signal (3.2V Range) 70 dBFS
THD Total Harmonic Distortion 5MHz Input Signal, First 5 Harmonics (2V Range) 92 dB
5MHz Input Signal, First 5 Harmonics (3.2V Range) 90 dB
30MHz Input Signal, First 5 Harmonics (2V Range) 90.5 dB
30MHz Input Signal, First 5 Harmonics (3.2V Range) 85.5 dB
70MHz Input Signal, First 5 Harmonics (2V Range) –77.5 dB
70MHz Input Signal, First 5 Harmonics (3.2V Range) –70 dB
IMD Intermodulation Distortion f
IN1
= 4MHz, f
IN2
= 5.1MHz (2V Range) 86 dBc
f
IN1
= 4MHz, f
IN2
= 5.1MHz (3.2V Range) 84 dBc
Sample-and-Hold Bandwidth R
SOURCE
= 50 240 MHz
The indicates specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. A
IN
= –1dBFS. (Note 5)
DY A IC ACCURACY
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PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CM
Output Voltage I
OUT
= 0 2.29 2.35 2.41 V
V
CM
Output Tempco I
OUT
= 0 ±30 ppm/°C
V
CM
Line Regulation 4.75V V
DD
5.25V 3 mV/V
V
CM
Output Resistance 1mA I
OUT
1mA 4
(Note 5)
I TER AL REFERE CE CHARACTERISTICS
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LTC1746IFW#TRPBF

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
Analog to Digital Converters - ADC L Pwr,14-B, 25Msps ADC
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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