LTC1418
Low Power, 14-Bit, 200ksps
ADC with Serial and Parallel I/O
FEATURES
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DESCRIPTION
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
Single Supply 5V or
±5V
Operation
Sample Rate: 200ksps
±1.25LSB
INL and
±1LSB
DNL Max
Power Dissipation: 15mW (Typ)
Parallel or Serial Data Output
No Missing Codes Over Temperature
Power Shutdown: Nap and Sleep
External or Internal Reference
Differential High Impedance Analog Input
Input Range: 0V to 4.096V or
±2.048V
81.5dB S/(N + D) and – 94dB THD at Nyquist
28-Pin Narrow PDIP and SSOP Packages
APPLICATIONS
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Remote Data Acquisition
Battery Operated Systems
Digital Signal Processing
Isolated Data Acquisition Systems
Audio and Telecom Processing
Medical Instrumentation
TYPICAL APPLICATION
Low Power, 200kHz, 14-Bit Sampling A/D Converter
5V
10µF
V
DD
LTC1418
A
IN+
S/H
A
IN
–
SER/PAR
D13
14-BIT ADC
14
SELECTABLE
SERIAL/
PARALLEL
PORT
D5
D4 (EXTCLKIN)
D3 (SCLK)
D2 (CLKOUT)
D1 (D
OUT
)
D0 (EXT/INT)
BUSY
CS
RD
CONVST
SHDN
1.0
0.5
INL (LSBs)
4.096V
REFCOMP
10µF
BUFFER
–0.5
8k
V
REF
1µF
AGND
V
SS
(0V OR – 5V)
DGND
1418 TA02
1418 TA01
2.5V
REFERENCE
TIMING AND
LOGIC
–1.0
0
4096
8192
OUTPUT CODE
12288
16384
U
0
U
U
Typical INL Curve
1
LTC1418
ABSOLUTE
MAXIMUM
RATINGS
(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 V
DD
27 V
SS
26 BUSY
25 CS
24 CONVST
23 RD
22 SHDN
21 SER/PAR
20 D0 (EXT/INT)
19 D1 (D
OUT
)
18 D2 (CLKOUT)
17 D3 (SCLK)
16 D4 (EXTCLKIN)
15 D5
N PACKAGE
28-LEAD NARROW PDIP
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
ORDER PART
NUMBER
LTC1418ACG
LTC1418ACN
LTC1418AIG
LTC1418AIN
LTC1418CG
LTC1418CN
LTC1418IG
LTC1418IN
D9 10
D8 11
D7 12
D6 13
DGND 14
G PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 110°C,
θ
JA
= 95°C/ W (G)
T
JMAX
= 110°C,
θ
JA
= 100°C/ W (N)
Consult factory for Military 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)
Internal Reference
External Reference = 2.5V
(Note 7)
CONDITIONS
With internal reference (Notes 5, 6) unless otherwise noted.
LTC1418
MIN
TYP
MAX
q
q
q
q
LTC1418A
MIN
TYP
MAX
14
±0.5
±0.35
±2
±20
±5
±10
±20
±1
±1.25
±1
±10
±60
±15
±45
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
ppm/°C
ppm/°C
13
±0.8
±0.7
±5
±10
±5
±2
±1.5
±20
±60
±30
I
OUT(REF)
= 0, Internal Reference, Commercial
I
OUT(REF)
= 0, Internal Reference, Industrial
I
OUT(REF)
= 0, External Reference
q
±15
±5
A ALOG I PUT
SYMBOL PARAMETER
V
IN
I
IN
C
IN
t
ACQ
(Note 5)
CONDITIONS
4.75V
≤
V
DD
≤
5.25V (Unipolar)
4.75V
≤
V
DD
≤
5.25V, – 5.25V
≤
V
SS
≤
– 4.75V (Bipolar)
CS = High
Between Conversions (Sample Mode)
During Conversions (Hold Mode)
Commercial
Industrial
q
q
q
q
q
MIN
TYP
0 to 4.096
±2.048
MAX
UNITS
V
V
Analog Input Range (Note 9)
Analog Input Leakage Current
Analog Input Capacitance
Sample-and-Hold Acquisition Time
±1
25
5
300
300
1000
1000
2
U
W
U
U
W W
W
U
U
U
µA
pF
pF
ns
ns
LTC1418
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
CONDITIONS
I
OUT
= 0
I
OUT
= 0, Commercial
I
OUT
= 0, Industrial
4.75V
≤
V
DD
≤
5.25V
– 5.25V
≤
V
SS
≤
– 4.75V
0.1mA
≤
I
OUT
≤
0.1mA
DIGITAL I PUTS AND OUTPUTS
SYMBOL PARAMETER
V
IH
V
IL
I
IN
C
IN
V
OH
V
OL
I
OZ
C
OZ
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
Hi-Z Output Leakage D13 to D0
Hi-Z Output Capacitance D13 to D0
Output Source Current
Output Sink Current
CONDITIONS
V
DD
= 5.25V
V
DD
= 4.75V
POWER REQUIRE E TS
SYMBOL PARAMETER
V
DD
V
SS
I
DD
Positive Supply Voltage (Notes 10, 11)
Negative Supply Voltage (Note 10)
Positive Supply Current
I
SS
Negative Supply Current
Nap Mode
Sleep Mode
P
DIS
Power Dissipation
UW
U
U
U
W U
U
(Note 5)
CONDITIONS
97.5kHz Input Signal
100kHz Input Signal, First 5 Harmonics
100kHz Input Signal
f
IN1
= 97.7kHz, f
IN2
= 104.2kHz
S/(N + D)
≥
77dB
q
q
q
MIN
79
86
TYP
81.5
– 94
95
– 90
5
0.5
MAX
– 86
UNITS
dB
dB
dB
dB
MHz
MHz
U
(Note 5)
MIN
2.480
q
TYP
2.500
±10
±20
0.05
0.05
8
MAX
2.520
±45
UNITS
V
ppm/°C
ppm/°C
LSB/ V
LSB/ V
kΩ
(Note 5)
MIN
q
q
q
TYP
MAX
0.8
±10
UNITS
V
V
µA
pF
V
V
2.4
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 to V
DD
, CS High
CS High (Note 9)
V
OUT
= 0V
V
OUT
= V
DD
1.4
4.74
q
q
q
q
4.0
0.05
0.10
0.4
±10
15
– 10
10
V
V
µA
pF
mA
mA
(Note 5)
CONDITIONS
Bipolar Only (V
SS
= 0V for Unipolar)
Unipolar, RD High (Note 5)
Bipolar, RD High (Note 5)
SHDN = 0V, CS = 0V (Note 12)
SHDN = 0V, CS = 5V (Note 12)
Bipolar, RD High (Note 5)
SHDN = 0V, CS = 0V (Note 12)
SHDN = 0V, CS = 5V (Note 12)
Unipolar
Bipolar
q
q
MIN
4.75
– 4.75
TYP
MAX
5.25
– 5.25
UNITS
V
V
mA
mA
µA
µA
mA
µA
µA
mW
mW
Nap Mode
Sleep Mode
3.0
3.9
570
2
1.4
0.1
0.1
15.0
26.5
4.3
4.5
q
1.8
q
q
21.5
31.5
3
LTC1418
TI I G CHARACTERISTICS
SYMBOL
f
SAMPLE(MAX)
t
CONV
t
ACQ
t
ACQ
+ t
CONV
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
PARAMETER
Maximum Sampling Frequency
Conversion Time
Acquisition Time
Acquisition Plus Conversion Time
CS to RD Setup Time
CS↓ to CONVST↓ Setup Time
CS↓ to SHDN↓ Setup Time to Ensure Nap Mode
SHDN↑ to CONVST↓ Wake-Up Time from Nap Mode
CONVST Low Time
CONVST to BUSY Delay
Data Ready Before BUSY↑
q
t
11
t
12
t
13
t
14
t
15
f
SCLK
f
EXTCLKIN
t
dEXTCLKIN
t
H SCLK
t
L SCLK
t
H EXTCLKIN
t
L EXTCLKIN
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.
4
UW
(Note 5)
CONDITIONS
q
q
q
q
MIN
200
TYP
3.4
0.3
3.7
MAX
4
1
5
UNITS
kHz
µs
µs
µs
ns
ns
ns
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
(Note 10)
(Notes 10, 11)
CL = 25pF
q
q
q
0
40
40
500
40
35
20
15
500
–5
15
30
40
40
55
20
25
30
35
70
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
q
q
Delay Between Conversions
Wait Time RD↓ After BUSY↑
Data Access Time After RD↓
(Note 10)
C
L
= 25pF
q
q
q
C
L
= 100pF
q
20
8
Bus Relinquish Time
Commercial
Industrial
RD Low Time
CONVST High Time
Delay Time, SCLK↓ to D
OUT
Valid
Time from Previous Data Remain Valid After SCLK↓
Shift Clock Frequency
External Conversion Clock Frequency
Delay Time, CONVST↓ to External Conversion Clock Input
SCLK High Time
SCLK Low Time
EXTCLKIN High Time
EXTCLKIN Low Time
C
L
= 25pF (Note 9)
C
L
= 25pF (Note 9)
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
(Notes 9, 10)
10
20
q
q
q
q
q
t
10
40
35
15
0
0.03
25
12.5
4.5
533
70
ns
ns
MHz
MHz
µs
ns
ns
250
250
ns
ns
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 2.1µs 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.
LTC1418
TYPICAL PERFORMANCE CHARACTERISTICS
Typical INL Curve
1.0
SIGNAL/(NOISE + DISTORTION) (dB)
0.5
DNL ERROR (LSBs)
INL (LSBs)
0
–0.5
–1.0
0
4096
8192
OUTPUT CODE
1418 TA02
12288
Signal-to-Noise Ratio
vs Input Frequency
AMPLITUDE (dB BELOW THE FUNDAMENTAL)
90
80
SIGNAL-TO -NOISE RATIO (dB)
SPURIOUS-FREE DYNAMIC RANGE (dB)
70
60
50
40
30
20
10
0
1k
10k
100k
INPUT FREQUENCY (Hz)
1M
1418 G02
Nonaveraged, 4096 Point FFT,
Input Frequency = 10kHz
0
–20
AMPLITUDE (dB)
f
SAMPLE
= 200kHz
f
IN
= 9.9609375kHz
SFDR = 99.32
SINAD = 82.4
AMPLITUDE (dB)
–40
–60
–80
–40
–60
–80
AMPLITUDE (dB)
–100
–120
0
10 20
30 40 50 60 70 80 90 100
FREQUENCY (kHz)
1418 F02a
U W
Differential Nonlinearity
vs Output Code
1.0
90
80
70
60
50
40
30
20
10
0
S/(N + D) vs Input Frequency
and Amplitude
V
IN
= 0dB
V
IN
= –20dB
0.5
0
– 0.5
V
IN
= –60dB
–1.0
16384
0
4096
12288
8192
OUTPUT CODE
16384
1418 G06
1k
100k
10k
INPUT FREQUENCY (Hz)
1M
1418 G01
Distortion vs Input Frequency
0
–20
–40
–60
–80
–100
–120
3RD
THD
2ND
0
–20
–40
–60
–80
–100
Spurious-Free Dynamic Range
vs Input Frequency
1k
10k
100k
INPUT FREQUENCY (Hz)
1M
1418 G03
–120
10k
100k
INPUT FREQUENCY (Hz)
1M
1418 G04
Nonaveraged, 4096 Point FFT,
Input Frequency = 100kHz
0
–20
f
SAMPLE
= 200kHz
f
IN
= 97.509765kHz
SFDR = 94.29
SINAD = 81.4
0
– 20
– 40
– 60
– 80
Intermodulation Distortion Plot
f
SAMPLE
= 200kHz
f
IN1
= 97.65625kHz
f
IN2
= 104.248046kHz
–100
–120
–100
–120
0
10 20
30 40 50 60 70 80 90 100
FREQUENCY (kHz)
1418 F02b
0
10 20 30 40 50 60 70 80 90 100
FREQUENCY (kHz)
1418 G05
5
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