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1
LTC1418
Low Power, 14-Bit, 200ksps
ADC with Serial and Parallel I/O
OUTPUT CODE
4096
0
1.0
INL (LSBs)
0.5
0
0.5
1.0
8192
1418 TA02
12288
16384
Typical INL Curve
The LTC
1418 is a low power, 200ksps, 14-bit A/D
converter. Data output is selectable for 14-bit parallel or
serial format. This versatile device can operate from a
single 5V or
5V supply. An onboard high performance
sample-and-hold, a precision reference and internal tim-
ing minimize external circuitry requirements. The low
15mW power dissipation is made even more attractive
with two user selectable power shutdown modes.
The LTC1418 converts 0V to 4.096V unipolar inputs from
a single 5V supply and
2.048V bipolar inputs from
5V
supplies. DC specs include
1.25LSB INL,
1LSB DNL
and no missing codes over temperature. Outstanding AC
performance includes 82dB S/(N + D) and 94dB THD at the
Nyquist input frequency of 100kHz.
The flexible output format allows either parallel or serial I/O.
The SPI/MICROWIRE
TM
compatible serial I/O port can oper-
ate as either master or slave and can support clock frequen-
cies from DC to 10MHz. A separate convert start input and
a data ready signal (BUSY) allow easy control of conversion
start and data transfer.
DESCRIPTIO
N
U
FEATURES
s
Single Supply 5V or
5V Operation
s
Sample Rate: 200ksps
s
1.25LSB INL and
1LSB DNL Max
s
Power Dissipation: 15mW (Typ)
s
Parallel or Serial Data Output
s
No Missing Codes Over Temperature
s
Power Shutdown: Nap and Sleep
s
External or Internal Reference
s
Differential High Impedance Analog Input
s
Input Range: 0V to 4.096V or
2.048V
s
81.5dB S/(N + D) and 94dB THD at Nyquist
s
28-Pin Narrow PDIP and SSOP Packages
TYPICAL APPLICATIO
N
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
s
Remote Data Acquisition
s
Battery Operated Systems
s
Digital Signal Processing
s
Isolated Data Acquisition Systems
s
Audio and Telecom Processing
s
Medical Instrumentation
APPLICATIO
N
S
U
S/H
14
BUFFER
8k
10
F
10
F
REFCOMP
A
IN
A
IN
+
V
REF
4.096V
5V
LTC1418
14-BIT ADC
SELECTABLE
SERIAL/
PARALLEL
PORT
D13
DGND
1418 TA01
V
SS
(0V OR 5V)
AGND
SER/PAR
D5
D4 (EXTCLKIN)
D3 (SCLK)
D2 (CLKOUT)
D1 (D
OUT
)
D0 (EXT/INT)
V
DD
TIMING AND
LOGIC
2.5V
REFERENCE
BUSY
CS
RD
CONVST
SHDN
1
F
Low Power, 200kHz, 14-Bit Sampling A/D Converter
2
LTC1418
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
W
U
(Notes 1, 2)
Supply Voltage (V
DD
) ................................................. 6V
Negative Supply Voltage (V
SS
)
Bipolar Operation Only ........................... 6V to GND
Total Supply Voltage (V
DD
to V
SS
)
Bipolar Operation Only ....................................... 12V
Analog Input Voltage (Note 3)
Unipolar Operation .................. 0.3V to (V
DD
+ 0.3V)
Bipolar Operation........... (V
SS
0.3V) to (V
DD
+ 0.3V)
Digital Input Voltage (Note 4)
Unipolar Operation ................................ 0.3V to 10V
Bipolar Operation.........................(V
SS
0.3V) to 10V
Digital Output Voltage
Unipolar Operation .................. 0.3V to (V
DD
+ 0.3V)
Bipolar Operation........... (V
SS
0.3V) to (V
DD
+ 0.3V)
Power Dissipation .............................................. 500mW
Operation Temperature Range
LTC1418C................................................ 0
C to 70
C
LTC1418I ............................................ 40
C to 85
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
PACKAGE/ORDER I
N
FOR
M
ATIO
N
W
U
U
ORDER PART
NUMBER
Consult factory for Military grade parts.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TOP VIEW
G PACKAGE
28-LEAD PLASTIC SSOP
N PACKAGE
28-LEAD NARROW PDIP
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
DGND
V
DD
V
SS
BUSY
CS
CONVST
RD
SHDN
SER/PAR
D0 (EXT/INT)
D1 (D
OUT
)
D2 (CLKOUT)
D3 (SCLK)
D4 (EXTCLKIN)
D5
LTC1418ACG
LTC1418ACN
LTC1418AIG
LTC1418AIN
LTC1418CG
LTC1418CN
LTC1418IG
LTC1418IN
C
C
HARA TERISTICS
CO
U
VERTER
LTC1418
LTC1418A
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Resolution (No Missing Codes)
q
13
14
Bits
Integral Linearity Error
(Note 7)
q
0.8
2
0.5
1.25
LSB
Differential Linearity Error
q
0.7
1.5
0.35
1
LSB
Offset Error
(Note 8)
q
5
20
2
10
LSB
Full-Scale Error
Internal Reference
10
60
20
60
LSB
External Reference = 2.5V
5
30
5
15
LSB
Full-Scale Tempco
I
OUT(REF)
= 0, Internal Reference, Commercial
q
15
10
45
ppm/
C
I
OUT(REF)
= 0, Internal Reference, Industrial
20
ppm/
C
I
OUT(REF)
= 0, External Reference
5
1
ppm/
C
With internal reference (Notes 5, 6) unless otherwise noted.
PUT
U
I
A
A
U
LOG
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Analog Input Range (Note 9)
4.75V
V
DD
5.25V (Unipolar)
q
0 to 4.096
V
4.75V
V
DD
5.25V, 5.25V
V
SS
4.75V (Bipolar)
q
2.048
V
I
IN
Analog Input Leakage Current
CS = High
q
1
A
C
IN
Analog Input Capacitance
Between Conversions (Sample Mode)
25
pF
During Conversions (Hold Mode)
5
pF
t
ACQ
Sample-and-Hold Acquisition Time
Commercial
q
300
1000
ns
Industrial
q
300
1000
ns
(Note 5)
T
JMAX
= 110
C,
JA
= 95
C/ W (G)
T
JMAX
= 110
C,
JA
= 100
C/ W (N)
3
LTC1418
(Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
S/(N + D) Signal-to-Noise Plus Distortion Ratio
97.5kHz Input Signal
q
79
81.5
dB
THD
Total Harmonic Distortion
100kHz Input Signal, First 5 Harmonics
q
94
86
dB
SFDR
Spurious Free Dynamic Range
100kHz Input Signal
q
86
95
dB
IMD
Intermodulation Distortion
f
IN1
= 97.7kHz, f
IN2
= 104.2kHz
90
dB
Full Power Bandwidth
5
MHz
Full Linear Bandwidth
S/(N + D)
77dB
0.5
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, Commercial
q
10
45
ppm/
C
I
OUT
= 0, Industrial
20
ppm/
C
V
REF
Line Regulation
4.75V
V
DD
5.25V
0.05
LSB/ V
5.25V
V
SS
4.75V
0.05
LSB/ V
V
REF
Output Resistance
0.1mA
I
OUT
0.1mA
8
k
(Note 5)
DIGITAL I PUTS A
N
D OUTPUTS
U
U
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
1.4
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
OZ
Hi-Z Output Leakage D13 to D0
V
OUT
= 0V to V
DD
, CS High
q
10
A
C
OZ
Hi-Z Output Capacitance D13 to D0
CS High (Note 9)
q
15
pF
I
SOURCE
Output Source Current
V
OUT
= 0V
10
mA
I
SINK
Output Sink Current
V
OUT
= V
DD
10
mA
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
DD
Positive Supply Voltage (Notes 10, 11)
4.75
5.25
V
V
SS
Negative Supply Voltage (Note 10)
Bipolar Only (V
SS
= 0V for Unipolar)
4.75
5.25
V
I
DD
Positive Supply Current
Unipolar, RD High (Note 5)
q
3.0
4.3
mA
Bipolar, RD High (Note 5)
q
3.9
4.5
mA
Nap Mode
SHDN = 0V, CS = 0V (Note 12)
570
A
Sleep Mode
SHDN = 0V, CS = 5V (Note 12)
2
A
I
SS
Negative Supply Current
Bipolar, RD High (Note 5)
q
1.4
1.8
mA
Nap Mode
SHDN = 0V, CS = 0V (Note 12)
0.1
A
Sleep Mode
SHDN = 0V, CS = 5V (Note 12)
0.1
A
P
DIS
Power Dissipation
Unipolar
q
15.0
21.5
mW
Bipolar
q
26.5
31.5
mW
(Note 5)
POWER REQUIRE E TS
W
U
4
LTC1418
TI I G CHARACTERISTICS
W U
(Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
f
SAMPLE(MAX)
Maximum Sampling Frequency
q
200
kHz
t
CONV
Conversion Time
q
3.4
4
s
t
ACQ
Acquisition Time
q
0.3
1
s
t
ACQ
+ t
CONV
Acquisition Plus Conversion Time
q
3.7
5
s
t
1
CS to RD Setup Time
(Notes 9, 10)
q
0
ns
t
2
CS
to CONVST
Setup Time
(Notes 9, 10)
q
40
ns
t
3
CS
to SHDN
Setup Time to Ensure Nap Mode
(Notes 9, 10)
q
40
ns
t
4
SHDN
to CONVST
Wake-Up Time from Nap Mode
(Note 10)
500
ns
t
5
CONVST Low Time
(Notes 10, 11)
q
40
ns
t
6
CONVST to BUSY Delay
CL = 25pF
q
35
70
ns
t
7
Data Ready Before BUSY
20
35
ns
q
15
ns
t
8
Delay Between Conversions
(Note 10)
q
500
ns
t
9
Wait Time RD
After BUSY
q
5
ns
t
10
Data Access Time After RD
C
L
= 25pF
15
30
ns
q
40
ns
C
L
= 100pF
20
40
ns
q
55
ns
t
11
Bus Relinquish Time
8
20
ns
Commercial
q
25
ns
Industrial
q
30
ns
t
12
RD Low Time
q
t
10
ns
t
13
CONVST High Time
40
ns
t
14
Delay Time, SCLK
to D
OUT
Valid
C
L
= 25pF (Note 9)
q
35
70
ns
t
15
Time from Previous Data Remain Valid After SCLK
C
L
= 25pF (Note 9)
q
15
25
ns
f
SCLK
Shift Clock Frequency
(Notes 9, 10)
0
12.5
MHz
f
EXTCLKIN
External Conversion Clock Frequency
(Notes 9, 10)
0.03
4.5
MHz
t
dEXTCLKIN
Delay Time, CONVST
to External Conversion Clock Input
(Notes 9, 10)
533
s
t
H SCLK
SCLK High Time
(Notes 9, 10)
10
ns
t
L SCLK
SCLK Low Time
(Notes 9, 10)
20
ns
t
H EXTCLKIN
EXTCLKIN High Time
(Notes 9, 10)
250
ns
t
L EXTCLKIN
EXTCLKIN Low Time
(Notes 9, 10)
250
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
CC
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
= 0V or 5V, f
SAMPLE
= 200kHz, t
r
= t
f
= 5ns unless
otherwise specified.
Note 6: Linearity, offset and full-scale specifications apply for a single-
ended 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: Guaranteed by design, not subject to test.
Note 10: Recommended operating conditions.
Note 11: The falling edge of CONVST starts a conversion. If CONVST
returns high at a critical point during the conversion, it can create small
errors. For best performance ensure that CONVST returns high either
within 2.1
s after the conversion starts or after BUSY rises.
Note 12: Pins 16 (D4/EXTCLKIN), 17 (D3/SCLK) and 20 (DO/EXT/INT) at
0V or 5V. See Power Shutdown.
5
LTC1418
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
FREQUENCY (kHz)
0
120
AMPLITUDE (dB)
100
80
60
40
20
50
70
100
1418 G05
20
0
10
30 40
60
80
90
f
SAMPLE
= 200kHz
f
IN1
= 97.65625kHz
f
IN2
= 104.248046kHz
Intermodulation Distortion Plot
FREQUENCY (kHz)
0
10
30
50
70
90
AMPLITUDE (dB)
0
20
40
60
80
100
120
20
40
60
80
1418 F02a
100
f
SAMPLE
= 200kHz
f
IN
= 9.9609375kHz
SFDR = 99.32
SINAD = 82.4
Nonaveraged, 4096 Point FFT,
Input Frequency = 10kHz
INPUT FREQUENCY (Hz)
10k
SPURIOUS-FREE DYNAMIC RANGE (dB)
100k
1M
1418 G04
0
20
40
60
80
100
120
S/(N + D) vs Input Frequency
and Amplitude
INPUT FREQUENCY (Hz)
SIGNAL/(NOISE + DISTORTION) (dB)
90
80
70
60
50
40
30
20
10
0
1k
100k
1M
1418 G01
10k
V
IN
= 60dB
V
IN
= 0dB
V
IN
= 20dB
FREQUENCY (kHz)
0
10
30
50
70
90
AMPLITUDE (dB)
0
20
40
60
80
100
120
20
40
60
80
1418 F02b
100
f
SAMPLE
= 200kHz
f
IN
= 97.509765kHz
SFDR = 94.29
SINAD = 81.4
Nonaveraged, 4096 Point FFT,
Input Frequency = 100kHz
Typical INL Curve
OUTPUT CODE
4096
0
1.0
INL (LSBs)
0.5
0
0.5
1.0
8192
1418 TA02
12288
16384
OUTPUT CODE
0
1.0
DNL ERROR (LSBs)
0.5
0
0.5
1.0
4096
8192
1418 G06
12288
16384
Differential Nonlinearity
vs Output Code
INPUT FREQUENCY (Hz)
AMPLITUDE (dB BELOW THE FUNDAMENTAL)
0
20
40
60
80
100
120
1418 G03
1k
100k
1M
10k
THD
2ND
3RD
Distortion vs Input Frequency
Spurious-Free Dynamic Range
vs Input Frequency
Signal-to-Noise Ratio
vs Input Frequency
INPUT FREQUENCY (Hz)
SIGNAL-TO -NOISE RATIO (dB)
1k
0
90
80
70
60
50
40
30
20
10
1418 G02
100k
1M
10k
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