1
LTC1414
14-Bit, 2.2Msps,
Sampling A/D Converter
Effective Bits and Signal-to-Noise + Distortion
vs Input Frequency
14-BIT ADC
14
5V
OPTIONAL 3V
LOGIC SUPPLY
10
F
AV
DD
DV
DD
OV
DD
OGND
1414 TA01
DGND
D13 (MSB)
D0 (LSB)
BUSY
S/H
BUFFER
LTC1414
4.0625V
2k
5V
2.5V
REFERENCE
TIMING AND
LOGIC
OUTPUT
BUFFERS
CONVST
AGND
V
SS
10
F
10
F
V
REF
COMP
A
IN
A
IN
+
1
F
INPUT FREQUENCY (Hz)
EFFECTIVE BITS
S/(N + D) (dB)
10k
100k
1M
10M
1414 TA02
1k
14
13
12
11
10
9
8
7
6
5
4
3
2
86
80
74
68
f
SAMPLE
= 2.2MHz
TYPICAL APPLICATIO
U
The LTC
1414 is a 14-bit, 2.2Msps, sampling A/D con-
verter which draws only 175mW from
5V supplies. This
high performance ADC includes a high dynamic range
sample-and-hold, a precision reference and requires no
external components.
The LTC1414's high performance sample-and-hold has a
full-scale input range of
2.5V. Outstanding AC perfor-
mance includes 80dB S/(N + D) and 95dB SFDR with a
100kHz input. The performance remains high at the Nyquist
input frequency of 1.1MHz with 78dB S/(N + D) and 84dB
SFDR.
The unique differential input sample-and-hold can acquire
single-ended or differential input signals up to its 40MHz
bandwidth. The 70dB common mode rejection can elimi-
nate ground loops and common mode noise by measuring
signal differentially from the source
The ADC has a microprocessor compatible, 14-bit parallel
output port. There is no pipline delay in the conversion
results.
s
Sample Rate: 2.2Msps
s
Outstanding Spectral Purity:
80dB S/(N + D) and 95dB SFDR at 100kHz
78dB S/(N + D) and 84dB SFDR at Nyquist
s
Ultralow Distortion with Single-Ended or
Differential Inputs
s
2.5V Bipolar Input Range Eliminates Level Shifting
and Rail-to-Rail Op Amp Requirements
s
Easy Hookup for External or Internal Reference
s
No Pipeline Delay
s
Power Dissipation: 175mW on
5V Supplies
s
28-Pin Narrow SSOP Package
, LTC and LT are registered trademarks of Linear Technology Corporation.
FEATURES
DESCRIPTIO
U
s
Telecommunications
s
Digital Signal Processing
s
Multiplexed Data Acquisition Systems
s
High Speed Data Acquisition
s
Spectrum Analysis
s
Imaging Systems
APPLICATIO S
U
2
LTC1414
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
W
U
PACKAGE/ORDER I
N
FOR
M
ATIO
N
W
U
U
AV
DD
= OV
DD
= DV
DD
= V
DD
(Notes 1, 2)
Supply Voltage (V
DD
) ................................................. 6V
Negative Supply Voltage (V
SS
) ................................ 6V
Total Supply Voltage (V
DD
to V
SS
) .......................... 12V
Analog Input Voltage
(Note 3) ......................... (V
SS
0.3V) to (V
DD
+ 0.3V)
Digital Input Voltage (Note 4) ..........(V
SS
0.3V) to 10V
Digital Output Voltage ........ (V
SS
0.3V) to (V
DD
+ 0.3V)
Power Dissipation .............................................. 500mW
Operating Temperature Range ..................... 0
C to 70
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
ORDER PART
NUMBER
T
JMAX
= 110
C,
JA
= 110
C/ W
Consult factory for Industrial, Military and A grade parts.
LTC1414CGN
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Analog Input Range
4.75V
V
DD
5.25V, 5.25V
V
SS
4.75V
q
2.5
V
I
IN
Analog Input Leakage Current
Between Conversions
q
1
A
C
IN
Analog Input Capacitance
Between Conversions
8
pF
During Conversions
4
pF
t
ACQ
Sample-and-Hold Acquisition Time
q
40
100
ns
t
AP
Sample-and-Hold Aperture Delay Time
1
ns
t
jitter
Sample-and-Hold Aperture Delay Time Jitter
3
ps
RMS
CMRR
Analog Input Common Mode Rejection Ratio
2.5V < (A
IN
= A
IN
+
) < 2.5V
70
dB
With internal reference (Notes 5, 6)
C
C
HARA TERISTICS
CO
U
VERTER
LTC1414
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Resolution (No Missing Codes)
q
13
Bits
Integral Linearity Error
(Note 7)
q
0.75
2.0
LSB
Differential Linearity Error
q
0.75
1.75
LSB
Offset Error
(Note 8)
5
20
LSB
q
24
LSB
Full-Scale Error
Internal Reference
10
60
LSB
External Reference = 2.5V
5
25
LSB
Full-Scale Tempco
Internal Reference
15
ppm/
C
External Reference = 2.5V
1
ppm/
C
PUT
U
I
A
A
U
LOG
(Note 5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TOP VIEW
GN PACKAGE
28-LEAD PLASTIC SSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
A
IN
+
A
IN
V
REF
REFCOMP
AGND
D13 (MSB)
D12
D11
D10
D9
D8
D7
D6
OGND
AV
DD
AGND
V
SS
BUSY
CONVST
DGND
DV
DD
OV
DD
D0
D1
D2
D3
D4
D5
3
LTC1414
(Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
S/(N + D) Signal-to-Noise Plus Distortion Ratio
100kHz Input Signal
80
dB
1.1MHz Input Signal
78
dB
THD
Total Harmonic Distortion
100kHz Input Signal, First 5 Harmonics
95
dB
1.1MHz Input Signal, First 5 Harmonics
83
dB
SFDR
Spurious Free Dynamic Range
100kHz Input Signal, First 5 Harmonics
95
dB
1.1MHz Input Signal, First 5 Harmonics
84
dB
IMD
Intermodulation Distortion
f
IN1
= 29.37kHz, f
IN2
= 32.446kHz
86
dB
Full Power Bandwidth
40
MHz
Full Linear Bandwidth
S/(N + D)
74dB
3
MHz
ACCURACY
IC
DY
U
W
A
(Note 5)
I TER AL REFERE CE CHARACTERISTICS
U
U
U
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
REF
Output Voltage
I
OUT
= 0
2.480
2.500
2.520
V
V
REF
Output Tempco
I
OUT
= 0
15
ppm/
C
V
REF
Line Regulation
4.75V
V
DD
5.25V
0.01
LSB/ V
5.25V
V
SS
4.75V
0.01
LSB/ V
V
REF
Output Resistance
I
OUT
0.1mA
2
k
COMP Output Voltage
I
OUT
= 0
4.06
V
(Note 5)
DIGITAL I PUTS A
N
D OUTPUTS
U
U
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
DD
Positive Supply Voltage
(Note 9)
4.75
5.25
V
V
SS
Negative Supply Voltage
(Note 9)
4.75
5.25
V
I
DD
Positive Supply Current
CS High
q
12
16
mA
I
SS
Negative Supply Current
CS High
q
23
30
mA
P
D
Power Dissipation
175
230
mW
POWER REQUIRE E TS
W
U
(Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
V
DD
= 5.25V
q
2.4
V
V
IL
Low Level Input Voltage
V
DD
= 4.75V
q
0.8
V
I
IN
Digital Input Current
V
IN
= 0V to V
DD
q
10
A
C
IN
Digital Input Capacitance
1.2
pF
V
OH
High Level Output Voltage
V
DD
= 4.75V, I
O
= 10
A
4.74
V
V
DD
= 4.75V, I
O
= 200
A
q
4.0
V
V
OL
Low Level Output Voltage
V
DD
= 4.75V, I
O
= 160
A
0.05
V
V
DD
= 4.75V, I
O
= 1.6mA
q
0.10
0.4
V
I
SOURCE
Output Source Current
V
OUT
= 0V
10
mA
I
SINK
Output Sink Current
V
OUT
= V
DD
10
mA
4
LTC1414
TI I G CHARACTERISTICS
W U
(Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
f
SAMPLE(MAX)
Maximum Sampling Frequency
q
2.2
MHz
t
CONV
Conversion Time
q
220
330
400
ns
t
ACQ
Acquisition Time
q
40
100
ns
t
THROUGHPUT
Throughput Time (Acquisition + Conversion)
q
370
454
ns
t
1
CONVST to BUSY Delay
C
L
= 25pF
10
ns
t
2
Data Ready Before BUSY
20
ns
t
3
Delay Between Conversions
(Note 9)
q
100
ns
t
4
CONVST Low Time
(Note 10)
q
40
ns
t
5
CONVST High Time
(Note 10)
q
40
ns
t
6
Aperture Delay of Sample-and-Hold
1
ns
The
q
denotes specifications which apply over the full operating
temperature range; all other limits and typicals T
A
= 25
C.
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 DGND and
AGND wired together (unless otherwise noted).
Note 3: When these pin voltages are taken below V
SS
or above V
DD
, they
will be clamped by internal diodes. This product can handle input currents
greater than 100mA below V
SS
or above V
DD
without latchup.
Note 4: When these pin voltages are taken below V
SS
, they will be clamped
by internal diodes. This product can handle input currents greater than
100mA below V
SS
without latchup. These pins are not clamped to V
DD
.
Note 5: V
DD
= 5V, V
SS
= 5V, f
SAMPLE
= 2.2MHz and t
r
= t
f
= 5ns unless
otherwise specified.
Note 6: Linearity, offset and full-scale specifications apply for a single-
ended A
IN
+
input with A
IN
grounded.
Note 7: 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 8: Bipolar offset is the offset voltage measured from 0.5LSB
when the output code flickers between 0000 0000 0000 00 and
1111 1111 1111 11.
Note 9: Recommended operating conditions.
Note 10: The falling CONVST edge starts a conversion. If CONVST returns
high at a critical point during the conversion it can create small errors. For
best results ensure that CONVST returns high either within 225ns after the
start of the conversion or after BUSY rises.
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Signal-to-Noise Ratio vs Input
Frequency
INPUT FREQUENCY (Hz)
10k
SIGNAL-TO-NOISE RATIO (dB)
90
80
70
60
50
40
30
20
10
0
100k
1M
10M
1414 G02
INPUT FREQUENCY (Hz)
10k
DISTORTION (dB)
0
10
20
30
40
50
60
70
80
90
100
100k
1M
10M
1414 G03
2nd
THD
3rd
INPUT FREQUENCY (Hz)
EFFECTIVE BITS
S/(N + D) (dB)
10k
100k
1M
10M
1414 TA02
1k
14
13
12
11
10
9
8
7
6
5
4
3
2
86
80
74
68
f
SAMPLE
= 2.2MHz
S/(N + D) vs Input Frequency
Distortion vs Input Frequency
5
LTC1414
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
PI
N
FU
N
CTIO
N
S
U
U
U
A
IN
+
(Pin 1): Positive Analog Input.
2.5V input range
when A
IN
is grounded.
2.5V differential if A
IN
is driven
differentially with A
IN
+
.
A
IN
(Pin 2): Negative Analog Input. Can be grounded or
driven differentially with A
IN
+
.
V
REF
(Pin 3): 2.5V Reference Output.
REFCOMP (Pin 4): 4.06V Reference Bypass Pin.
Bypass to AGND with 10
F ceramic or 10
F tantalum in
parallel with 0.1
F ceramic.
AGND (Pin 5): Analog Ground.
D13 to D6 (Pins 6 to 13): Data Outputs.
OGND (Pin 14): Digital Ground for the Output Drivers. Tie
to AGND
D5 to D0 (Pins 15 to 20): Data Outputs.
OV
DD
(Pin 21): Positive Supply for the Output Drivers. Tie
to Pin 28 when driving 5V logic. For 3V logic, tie to supply
of the logic being driven.
DV
DD
(Pin 22): 5V Positive Supply. Tie to Pin 28.
DGND (Pin 23): Digital Ground. Tie to AGND.
CONVST (Pin 24): Conversion Start Signal. This active low
signal starts a conversion on its falling edge.
Spurious-Free Dynamic Range vs
Input Frequency
Intermodulation Distortion Plot
Differential Nonlinearity vs
Output Code
INPUT FREQUENCY (Hz)
10k
SPURIOUS-FREE DYNAMIC RANGE (dB)
0
10
20
30
40
50
60
70
80
90
100
100k
1M
10M
1414 G04
OUTPUT CODE
0
4096
8192
12288
16384
DNL (LSBs)
1414 G06
2.0
1.0
0
1.0
2.0
Integral Nonlinearity vs Output
Code
Power Supply Feedthrough vs
Ripple Frequency
Input Common Mode Rejection vs
Input Frequency
INPUT FREQUENCY (Hz)
1k
COMMON MODE REJECTION (dB)
80
70
60
50
40
30
20
10
0
10k
100k
LTC1414 F12
1M
10M
OUTPUT CODE
0
4096
8192
12288
16384
INL (LSBs)
1414 G07
2.0
1.0
0
1.0
2.0
FREQUENCY (kHz)
0
400
800
200
600
1000
AMPLITUDE (dB)
1414 F05a
0
20
40
60
80
100
120
f
SAMPLE
= 2.2MHz
f
IN1
= 80.566kHz
f
IN2
= 97.753kHz
RIPPLE FREQUENCY (Hz)
0
2M
4M
6M
8M
10M
AMPLITUDE OF POWER SUPPLY
FEEDTHROUGH (dB)
1414 G08
0
20
40
60
80
100
120
V
SS
(V
RIPPLE
= 0.02V)
V
DD
(V
RIPPLE
= 0.2V)
OGND (V
RIPPLE
= 0.5V)
OV
DD
(V
RIPPLE
= 0.5V)
PDF 
ZIP