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Complete 12-Bit ADC in SO-8
Single Supply 5V or ±5V Operation
Sample Rate: 400ksps
Power Dissipation: 75mW (Typ)
72dB S/(N + D) and –80dB THD at Nyquist
No Missing Codes over Temperature
Nap Mode with Instant Wake-Up: 6mW
Sleep Mode: 30μW
High Impedance Analog Input
Input Range (1mV/LSB): 0V to 4.096V or ±2.048V
Internal Reference Can Be Overdriven Externally
3-Wire Interface to DSPs and Processors (SPI and
MICROWIRE
TM
Compatible)
The LTC
®
1400 is a complete 400ksps, 12-bit A/D converter
which draws only 75mW from 5V or ±5V supplies. This
easy-to-use device comes complete with a 200ns sample-
and-hold and a precision reference. Unipolar and bipolar
conversion modes add to the flexibility of the ADC. The
LTC1400 has two power saving modes: Nap and Sleep.
In Nap mode, it consumes only 6mW of power and can
wake up and convert immediately. In the Sleep mode, it
consumes 30μW of power typically. Upon power-up from
Sleep mode, a reference ready (REFRDY) signal is available
in the serial data word to indicate that the reference has
settled and the chip is ready to convert.
The LTC1400 converts 0V to 4.096V unipolar inputs from
a single 5V supply and ±2.048V bipolar inputs from ±5V
supplies. Maximum DC specs include ±1LSB INL, ±1LSB
DNL and 45ppm/°C drift over temperature. Guaranteed AC
performance includes 70dB S/(N + D) and –76dB THD at
an input frequency of 100kHz, over temperature.
The 3-wire serial port allows compact and efficient data
transfer to a wide range of microprocessors, microcon-
trollers and DSPs.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
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High Speed Data Acquisition
Digital Signal Processing
Multiplexed Data Acquisition Systems
Audio and Telecom Processing
Digital Radio
Spectrum Analysis
Low Power and Battery-Operated Systems
Handheld or Portable Instruments
Single 5V Supply, 400kHz, 12-Bit Sampling A/D Converter
5V
SUPPLY CURRENT (mA)
+
ANALOG INPUT
(0V TO 4.096V)
2.42V REF
OUT
10µF
V
CC
10µF
0.1µF
LTC1400
A
IN
V
REF
0.1µF
GND
+
U
TYPICAL APPLICATIO
Power Consumption vs Sample Rate
100
NORMAL CONVERSION
NAP MODE
BETWEEN CONVERSION
SLEEP AND NAP MODE
BETWEEN CONVERSION
SLEEP MODE BETWEEN
CONVERSION
6.4MHz CLOCK
10
V
SS
MPU
P1.4
P1.3
SERIAL
DATA LINK
P1.2
1
CONV
CLK
D
OUT
0.1
0.01
1400 TA01
0.001
0.01 0.1
U
FEATURES
LTC1400
Complete SO-8, 12-Bit,
400ksps ADC with
Shutdown
DESCRIPTIO
U
1
10 100 1k 10k 100k 1M
SAMPLE RATE (Hz)
1400 TA02
1400fa
1
LTC1400
(Note 1, 2)
Supply Voltage (V
CC
) ..................................................7V
Negative Supply Voltage (V
SS
) ..................... –6V to GND
Total Supply Voltage (V
CC
to V
SS
)
Bipolar Operation Only ..........................................12V
Analog Input Voltage (Note 3)
Unipolar Operation ....................–0.3V to (V
CC
+ 0.3V)
Bipolar Operation ........... (V
SS
– 0.3V) to (V
CC
+ 0.3V)
Digital Input Voltage (Note 4)
Unipolar Operation ................................. –0.3V to 12V
Bipolar Operation .........................(V
SS
– 0.3V) to 12V
Digital Output Voltage
Unipolar Operation ....................–0.3V to (V
CC
+ 0.3V)
Bipolar Operation ........... (V
SS
– 0.3V) to (V
CC
+ 0.3V)
Power Dissipation .............................................. 500mW
Operation Temperature Range
LTC1400C ................................................ 0°C to 70°C
LTC1400I ............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
TOP VIEW
V
CC
1
A
IN
2
V
REF
3
GND 4
8 V
SS
7 CONV
6 CLK
5 D
OUT
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 130°C/W
ORDER PART NUMBER
LTC1400CS8
LTC1400IS8
S8 PART MARKING
1400
1400I
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
POWER REQUIRE E TS
SYMBOL
V
CC
V
SS
I
CC
I
SS
P
D
PARAMETER
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
CONDITIONS
Unipolar
Bipolar
Bipolar Only
f
SAMPLE
= 400ksps
Nap Mode
Sleep Mode
f
SAMPLE
= 400ksps, V
SS
= –5V
Nap Mode
Sleep Mode
f
SAMPLE
= 400ksps
Nap Mode
Sleep Mode
●
●
●
●
●
●
●
●
●
MIN
4.75
4.75
–2.45
TYP
MAX
5.25
5.25
–5.25
UNITS
V
V
V
mA
mA
μA
mA
mA
μA
mW
mW
μW
Positive Supply Voltage (Note 6)
Negative Supply Voltage (Note 6)
Positive Supply Current
15
1.0
5.0
0.3
0.2
1
75
6
30
30
3.0
20.0
0.6
0.5
5
160
20
125
Negative Supply Current
Power Dissipation
A ALOG I PUT
SYMBOL
V
IN
I
IN
C
IN
PARAMETER
The
●
denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
CONDITIONS
4.75V ≤ V
CC
≤ 5.25V (Unipolar)
4.75V ≤ V
CC
≤ 5.25V, –5.25V ≤ V
SS
≤ –2.45V (Bipolar)
During Conversions (Hold Mode)
Between Conversions (Sample Mode)
During Conversions (Hold Mode)
●
●
●
MIN
TYP
0 to 4.096
±2.048
MAX
UNITS
V
V
Analog Input Range (Note 7)
Analog Input Leakage Current
Analog Input Capacitance
±1
45
5
1400fa
2
U
μA
pF
pF
W
U
U
W W
U W
W
ABSOLUTE
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
U
U
LTC1400
CO VERTER CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Full-Scale Error
Full-Scale Tempco
I
OUT(REF)
= 0
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C unless otherwise noted. With internal reference (Notes 5, 8)
CONDITIONS
●
DY A IC ACCURACY
SYMBOL
S/(N + D)
The
●
denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
SS
= –5V, f
SAMPLE
= 400kHz unless otherwise noted. (Note 5)
PARAMETER
Signal-to-Noise
Plus Distortion Ratio
Total Harmonic Distortion
Up to 5th Harmonic
Peak Harmonic or
Spurious Noise
CONDITIONS
100kHz Input Signal
200kHz Input Signal
Commercial
Industrial
●
●
THD
IMD
I TER AL REFERE CE CHARACTERISTICS
PARAMETER
V
REF
Output Voltage
V
REF
Output Tempco
V
REF
Load Regulation
V
REF
Load Regulation
V
REF
Wake-Up Time from Sleep Mode (Note 7)
The
●
denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
CONDITIONS
I
OUT
= 0
I
OUT
= 0
4.75V ≤ V
CC
≤ 5.25V
–5.25V ≤ V
SS
≤ 0V
0 ≤ |I
OUT
| ≤ 1mA
C
VREF
= 10μF
●
DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL
V
IH
V
IL
I
IN
C
IN
V
OH
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Digital Input Current
Digital Input Capacitance
High Level Output Voltage
The
●
denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
CONDITIONS
V
CC
= 5.25V
V
CC
= 4.75V
V
IN
= 0V to V
CC
V
CC
= 4.75V, I
O
= –10μA
V
CC
= 4.75V, I
O
= –200μA
●
●
●
U
U
U
W U
U
U
MIN
12
●
●
TYP
MAX
±1
±1
±6
±8
±15
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
(Note 9)
(Note 10)
●
±10
±45
MIN
70
69
TYP
72
72
MAX
UNITS
dB
dB
dB
100kHz Input Signal
200kHz Input Signal
100kHz Input Signal
200kHz Input Signal
f
IN1
= 99.51kHz, f
IN2
= 102.44kHz
f
IN1
= 199.12kHz, f
IN2
= 202.05kHz
●
●
–82
–80
–84
–82
–82
–70
4
900
–76
–76
dB
dB
dB
dB
dB
dB
MHz
kHz
Intermodulation Distortion
Full Power Bandwidth
Full Linear Bandwidth (S/(N + D) ≥ 68dB)
U
MIN
2.400
TYP
2.420
±10
0.01
0.01
2
4
MAX
2.440
±45
UNITS
V
ppm/°C
LSB/V
LSB/V
LSB/mA
ms
MIN
2.0
TYP
MAX
0.8
±10
UNITS
V
V
μA
pF
V
V
1400fa
5
●
4.0
4.7
3
LTC1400
DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL
V
OL
I
OZ
C
OZ
I
SOURCE
I
SINK
PARAMETER
Low Level Output Voltage
Hi-Z Output Leakage D
OUT
Hi-Z Output Capacitance D
OUT
(Note 7)
Output Source Current
Output Sink Current
V
OUT
= 0V
V
OUT
= V
CC
The
●
denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
CONDITIONS
V
CC
= 4.75V, I
O
= 160μA
V
CC
= 4.75V, I
O
= 1.6mA
V
OUT
= 0V to V
CC
●
●
TI I G CHARACTERISTICS
SYMBOL
t
CONV
t
ACQ
f
CLK
t
CLK
t
WK(NAP)
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
11
f
SAMPLE(MAX)
Maximum Sampling Frequency
Conversion Time
Acquisition Time
CLK Frequency
CLK Pulse Width
Time to Wake Up from Nap Mode
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C unless otherwise noted. (Note 5)
PARAMETER
CONDITIONS
(Note 6)
f
CLK
= 6.4MHz
(Unipolar Mode)
(Bipolar Mode V
SS
= –5V)
(Note 7)
●
●
●
●
●
CLK Pulse Width to Return to Active Mode
CONV↑ to CLK↑ Setup Time
CONV↑ After Leading CLK↑
CONV Pulse Width
Time from CLK↑ to Sample Mode
Aperture Delay of Sample-and-Hold
Minimum Delay Between Conversion
Delay Time, CLK↑ to D
OUT
Valid
Delay Time, CLK↑ to D
OUT
Hi-Z
Time from Previous Data Remains Valid After CLK↑
Minimum Time between Nap/Sleep Request to Wake Up Request
(Unipolar Mode)
(Bipolar Mode V
SS
= –5V)
C
LOAD
= 20pF
C
LOAD
= 20pF
C
LOAD
= 20pF
(Notes 7, 12)
(Note 11)
(Note 7)
Jitter < 50ps (Note 7)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All voltage values are with respect to GND.
Note 3:
When these pin voltages are taken below V
SS
(ground for unipolar
mode) or above V
CC
, they will be clamped by internal diodes. This product
can handle input currents greater than 40mA below V
SS
(ground for
unipolar mode) or above V
CC
without latch-up.
Note 4:
When these pin voltages are taken below V
SS
(ground for unipolar
mode), they will be clamped by internal diodes. This product can handle
input currents greater than 40mA below V
SS
(ground for unipolar mode)
without latch-up. These pins are not clamped to V
CC
.
Note 5:
V
CC
= 5V, f
SAMPLE
= 400kHz, t
r
= t
f
= 5ns unless otherwise
specified.
Note 6:
Recommended operating conditions.
4
U
U
MIN
TYP
0.05
0.10
15
–10
10
MAX
0.4
±10
UNITS
V
V
μA
pF
mA
mA
UW
MIN
400
TYP
MAX
2.1
UNITS
kHz
μs
ns
ns
MHz
ns
ns
ns
ns
ns
ns
230
200
0.1
50
350
50
80
0
50
80
45
265
235
40
40
14
50
25
300
270
6.4
(Notes 7, 12)
(Note 7)
●
●
●
●
●
ns
65
385
355
80
80
ns
ns
ns
ns
ns
ns
ns
●
●
●
●
●
●
●
Note 7:
Guaranteed by design, not subject to test.
Note 8:
Linearity, offset and full-scale specifications apply for unipolar and
bipolar modes.
Note 9:
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 10:
Bipolar offset is the offset voltage measured from –0.5LSB when
the output code flickers between 0000 0000 0000 and 1111 1111 1111.
Note 11:
The rising edge of CONV starts a conversion. If CONV returns
low at a bit decision point during the conversion, it can create small errors.
For best performance ensure that CONV returns low either within 120ns
after conversion starts (i.e., before the first bit decision) or after the 14
clock cycle. (Figure 13 Timing Diagram).
Note 12:
If this timing specification is not met, the device may not respond
to a request for a conversion. To recover from this condition a NAP
request is required.
1400fa
LTC1400
TYPICAL PERFOR A CE CHARACTERISTICS
Differential Nonlinearity vs
Output Code
1.00
DIFFERENTIAL NONLINEARITY (LSBs)
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
0
512 1024 1536 2048 2560 3072 3584 4096
OUTPUT CODE
1400 TPC01
f
SAMPLE
= 400kHz
INTEGRAL NONLINEARITY (LSBs)
SIGNAL/(NOISE + DISTORTION) (dB)
Signal-to-Noise Ratio (Without
Harmonics) vs Input Frequency
80
SPURIOUS-FREE DYNAMIC RANGE (dB)
70
SIGNAL-TO-NOISE RATIO (dB)
60
50
40
30
20
10
0
10
f
SAMPLE
= 400kHz
100
INPUT FREQUENCY (kHz)
1000
1400 TPC07
–30
–40
–50
–60
–70
–80
–90
10
100
INPUT FREQUENCY (kHz)
1000
1400 TPC08
ACQUISITION TIME (ns)
AMPLITUDE OF POWER SUPPLY FEEDTHROUGH (dB)
Reference Voltage vs
Load Current
2.435
2,430
REFERENCE VOLTAGE (V)
2.425
2.420
2.415
2.410
2.405
2.400
2.395
2.390
–8 –7 –6 –5 –4 –3 –2 –1
LOAD CURRENT (mA)
0
1
2
–30
–40
–50
–60
–70
–80
–90
1
V
CC
(V
RIPPLE
= 1mV)
10
100
RIPPLE FREQUENCY (kHz)
1000
1400 TPC07.5
SUPPLY CURRENT (mA)
U W
1400 TPC03
Integral Nonlinearity vs
Output Code
1.00
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
0
512 1024 1536 2048 2560 3072 3584 4096
OUTPUT CODE
1400 TPC02
S/(N + D) vs Input Frequency
and Amplitude
80
70
60
50
40
30
20
10
0
10
V
IN
= – 60dB
f
SAMPLE
= 400kHz
100
INPUT FREQUENCY (kHz)
1000
1400 TPC06
f
SAMPLE
= 400kHz
V
IN
= 0dB
V
IN
= –20dB
Peak Harmonic or Spurious Noise
vs Input Frequency
0
–10
–20
f
SAMPLE
= 400kHz
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Acquisition Time vs
Source Impedance
T
A
= 25°C
–100
10
100
1000
R
SOURCE
(Ω)
10000
1400 TPC05
Power Supply Feedthrough vs
Ripple Frequency
0
–10
–20
f
SAMPLE
= 400kHz
20
Supply Current vs Temperature
f
SAMPLE
= 400kHz
15
10
V
SS
(V
RIPPLE
= 10mV)
5
–100
0
–50 –25
0
25
50
75
TEMPERATURE (°C)
100
125
1400 TPC04
1400fa
5
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