LTC1414
14-Bit, 2.2Msps,
Sampling A/D Converter
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
s
Sample Rate: 2.2Msps
Outstanding Spectral Purity:
80dB S/(N + D) and 95dB SFDR at 100kHz
78dB S/(N + D) and 84dB SFDR at Nyquist
Ultralow Distortion with Single-Ended or
Differential Inputs
±2.5V
Bipolar Input Range Eliminates Level Shifting
and Rail-to-Rail Op Amp Requirements
Easy Hookup for External or Internal Reference
No Pipeline Delay
Power Dissipation: 175mW on
±5V
Supplies
28-Pin Narrow SSOP Package
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
s
s
Telecommunications
Digital Signal Processing
Multiplexed Data Acquisition Systems
High Speed Data Acquisition
Spectrum Analysis
Imaging Systems
TYPICAL APPLICATIO
5V
10µF
AV
DD
LTC1414
DV
DD
OPTIONAL 3V
LOGIC SUPPLY
Effective Bits and Signal-to-Noise + Distortion
vs Input Frequency
14
86
80
74
68
S/(N + D) (dB)
13
12
11
OV
DD
S/H
A
IN –
4.0625V
COMP
10µF
V
REF
1µF
V
SS
10µF
– 5V
BUFFER
2k
14-BIT ADC
OUTPUT
BUFFERS
•
•
•
EFFECTIVE BITS
A
IN
+
14
D13 (MSB)
10
9
8
7
6
5
4
D0 (LSB)
2.5V
REFERENCE
AGND
TIMING AND
LOGIC
DGND
OGND
BUSY
CONVST
3
2
1k
f
SAMPLE
= 2.2MHz
10k
100k
1M
INPUT FREQUENCY (Hz)
10M
1414 TA02
1414 TA01
U
U
U
1
LTC1414
ABSOLUTE
MAXIMUM
RATINGS
AV
DD
= OV
DD
= DV
DD
= V
DD
(Notes 1, 2)
PACKAGE/ORDER INFORMATION
TOP VIEW
A
IN+
A
IN–
V
REF
REFCOMP
AGND
D13 (MSB)
D12
D11
D10
1
2
3
4
5
6
7
8
9
28 AV
DD
27 AGND
26 V
SS
25 BUSY
24 CONVST
23 DGND
22 DV
DD
21 OV
DD
20 D0
19 D1
18 D2
17 D3
16 D4
15 D5
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
LTC1414C ............................................... 0°C to 70°C
LTC1414I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1414CGN
LTC1414IGN
D9 10
D8 11
D7 12
D6 13
OGND 14
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 110°C,
θ
JA
= 110°C/ W
Consult factory for Industrial, Military and A grade parts.
CO VERTER CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Full-Scale Error
Full-Scale Tempco
(Note 8)
(Note 7)
CONDITIONS
(Notes 5, 6)
MIN
q
q
q
q
LTC1414
TYP
±0.75
±0.75
±5
±10
±5
±15
±1
MAX
±2.0
±
1.75
±20
±24
±60
±25
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
LSB
ppm/°C
ppm/°C
13
Internal Reference
External Reference = 2.5V
Internal Reference
External Reference = 2.5V
A ALOG I PUT
SYMBOL PARAMETER
V
IN
I
IN
C
IN
t
ACQ
t
AP
t
jitter
CMRR
Analog Input Range
(Note 5)
CONDITIONS
4.75V
≤
V
DD
≤
5.25V, – 5.25V
≤
V
SS
≤
– 4.75V
Between Conversions
Between Conversions
During Conversions
q
q
q
MIN
TYP
±2.5
MAX
±1
UNITS
V
µA
pF
pF
Analog Input Leakage Current
Analog Input Capacitance
Sample-and-Hold Acquisition Time
Sample-and-Hold Aperture Delay Time
Sample-and-Hold Aperture Delay Time Jitter
Analog Input Common Mode Rejection Ratio
8
4
40
–1
3
100
ps
RMS
dB
– 2.5V < (A
IN–
= A
IN+
) < 2.5V
70
2
U
W
U
U
W W
W
U
U
U
ns
ns
LTC1414
DY A IC ACCURACY
SYMBOL PARAMETER
S/(N + D) Signal-to-Noise Plus Distortion Ratio
THD
SFDR
IMD
Total Harmonic Distortion
Spurious Free Dynamic Range
Intermodulation Distortion
Full Power Bandwidth
Full Linear Bandwidth
I TER AL REFERE CE CHARACTERISTICS
PARAMETER
V
REF
Output Voltage
V
REF
Output Tempco
V
REF
Line Regulation
V
REF
Output Resistance
COMP Output Voltage
CONDITIONS
I
OUT
= 0
I
OUT
= 0
4.75V
≤
V
DD
≤
5.25V
– 5.25V
≤
V
SS
≤
– 4.75V
I
OUT
≤
0.1mA
DIGITAL I PUTS AND OUTPUTS
SYMBOL PARAMETER
V
IH
V
IL
I
IN
C
IN
V
OH
V
OL
I
SOURCE
I
SINK
High Level Input Voltage
Low Level Input Voltage
Digital Input Current
Digital Input Capacitance
High Level Output Voltage
Low Level Output Voltage
Output Source Current
Output Sink Current
POWER REQUIRE E TS
SYMBOL PARAMETER
V
DD
V
SS
I
DD
I
SS
P
D
Positive Supply Voltage
Negative Supply Voltage
Positive Supply Current
Negative Supply Current
Power Dissipation
UW
U
U
U
W U
U
(Note 5)
CONDITIONS
100kHz Input Signal
1.1MHz Input Signal
100kHz Input Signal, First 5 Harmonics
1.1MHz Input Signal, First 5 Harmonics
100kHz Input Signal, First 5 Harmonics
1.1MHz Input Signal, First 5 Harmonics
f
IN1
= 29.37kHz, f
IN2
= 32.446kHz
S/(N + D)
≥
74dB
MIN
TYP
80
78
– 95
– 83
95
84
– 86
40
3
MAX
UNITS
dB
dB
dB
dB
dB
dB
dB
MHz
MHz
U
(Note 5)
MIN
2.480
TYP
2.500
±15
0.01
0.01
2
4.06
MAX
2.520
UNITS
V
ppm/°C
LSB/ V
LSB/ V
kΩ
V
I
OUT
= 0
(Note 5)
MIN
q
q
q
CONDITIONS
V
DD
= 5.25V
V
DD
= 4.75V
V
IN
= 0V to V
DD
V
DD
= 4.75V, I
O
= – 10µA
V
DD
= 4.75V, I
O
= – 200µA
V
DD
= 4.75V, I
O
= 160µA
V
DD
= 4.75V, I
O
= 1.6mA
V
OUT
= 0V
V
OUT
= V
DD
TYP
MAX
0.8
±10
UNITS
V
V
µA
pF
V
V
2.4
1.2
4.74
q
q
4.0
0.05
0.10
– 10
10
0.4
V
V
mA
mA
(Note 5)
CONDITIONS
(Note 9)
(Note 9)
CS High
CS High
q
q
MIN
4.75
– 4.75
TYP
MAX
5.25
– 5.25
UNITS
V
V
mA
mA
mW
12
23
175
16
30
230
3
LTC1414
TI I G CHARACTERISTICS
SYMBOL
f
SAMPLE(MAX)
t
CONV
t
ACQ
t
THROUGHPUT
t
1
t
2
t
3
t
4
t
5
t
6
PARAMETER
Maximum Sampling Frequency
Conversion Time
Acquisition Time
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.
TYPICAL PERFOR A CE CHARACTERISTICS
Signal-to-Noise Ratio vs Input
Frequency
86
80
SIGNAL-TO-NOISE RATIO (dB)
S/(N + D) vs Input Frequency
14
13
12
11
EFFECTIVE BITS
10
9
8
7
6
5
4
3
2
1k
f
SAMPLE
= 2.2MHz
10k
100k
1M
INPUT FREQUENCY (Hz)
10M
1414 TA02
60
50
40
30
20
10
0
10k
100k
1M
INPUT FREQUENCY (Hz)
10M
1414 G02
DISTORTION (dB)
4
U W
UW
(Note 5)
CONDITIONS
q
q
q
q
MIN
2.2
220
TYP
330
40
370
10
±20
MAX
400
100
454
UNITS
MHz
ns
ns
ns
ns
ns
ns
ns
ns
Throughput Time (Acquisition + Conversion)
CONVST to BUSY Delay
Data Ready Before BUSY↑
Delay Between Conversions
CONVST Low Time
CONVST High Time
Aperture Delay of Sample-and-Hold
(Note 9)
(Note 10)
(Note 10)
C
L
= 25pF
q
q
q
100
40
40
–1
ns
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.
Distortion vs Input Frequency
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
10k
100k
1M
INPUT FREQUENCY (Hz)
3rd
2nd
10M
1414 G03
90
80
70
74
68
S/(N + D) (dB)
THD
LTC1414
TYPICAL PERFOR A CE CHARACTERISTICS
Spurious-Free Dynamic Range vs
Input Frequency
0
SPURIOUS-FREE DYNAMIC RANGE (dB)
–10
–20
AMPLITUDE (dB)
–30
–40
–50
–60
–70
–80
–90
100k
1M
INPUT FREQUENCY (Hz)
10M
1414 G04
DNL (LSBs)
–100
10k
Integral Nonlinearity vs Output
Code
2.0
0
1.0
INL (LSBs)
AMPLITUDE OF POWER SUPPLY
FEEDTHROUGH (dB)
–20
–40
–60
–80
COMMON MODE REJECTION (dB)
0
–1.0
–2.0
0
4096
8192
12288
OUTPUT CODE
16384
1414 G07
PIN FUNCTIONS
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 10µF ceramic or 10µF tantalum in
parallel with 0.1µF 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.
U W
Intermodulation Distortion Plot
0
–20
–40
–60
–80
–1.0
–100
–120
0
200
400
600
800
FREQUENCY (kHz)
1000
1414 F05a
Differential Nonlinearity vs
Output Code
2.0
f
SAMPLE
= 2.2MHz
f
IN1
= 80.566kHz
f
IN2
= 97.753kHz
1.0
0
–2.0
0
4096
8192
12288
OUTPUT CODE
16384
1414 G06
Power Supply Feedthrough vs
Ripple Frequency
80
V
SS
(V
RIPPLE
= 0.02V)
V
DD
(V
RIPPLE
= 0.2V)
OGND (V
RIPPLE
= 0.5V)
OV
DD
(V
RIPPLE
= 0.5V)
70
60
50
40
30
20
10
0
0
2M
4M
6M
8M
RIPPLE FREQUENCY (Hz)
10M
1414 G08
Input Common Mode Rejection vs
Input Frequency
–100
–120
1k
1M
10k
100k
INPUT FREQUENCY (Hz)
10M
LTC1414 • F12
U
U
U
5
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