LTC1400
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATIO
U
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
V
CC
A
IN
V
REF
GND
V
SS
CONV
CLK
D
OUT
MPU
P1.4
P1.3
P1.2
LTC1400
+
0.1µF10µF
+
0.1µF10µF
2.42V REF
OUT
ANALOG INPUT
(0V TO 4.096V)
SERIAL
DATA LINK
5V
1400 TA01
SAMPLE RATE (Hz)
0.01
SUPPLY CURRENT (mA)
100
10
1
0.1
0.01
0.001
10 1k 1M
1400 TA02
0.1 1
100
10k 100k
NORMAL CONVERSION
NAP MODE
BETWEEN CONVERSION
SLEEP AND NAP MODE
BETWEEN CONVERSION
SLEEP MODE BETWEEN
CONVERSION
6.4MHz CLOCK
Complete SO-8, 12-Bit,
400ksps ADC with
Shutdown
■
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
MICROWIRETM Compatible)
■
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
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 sampleand-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, microcontrollers and DSPs.
Single 5V Supply, 400kHz, 12-Bit Sampling A/D Converter
Power Consumption vs Sample Rate
1400fa
1
LTC1400
WU
ABSOLUTE AXI U RATI GS
W
W W
U
PACKAGE/ORDER I FOR ATIO
U UW
TOP VIEW
V
CC
A
IN
V
REF
GND
V
SS
CONV
CLK
D
OUT
S8 PACKAGE
8-LEAD PLASTIC SO
1
2
3
4
8
7
6
5
UU
(Note 1, 2)
Supply Voltage (VCC) ..................................................7V
Negative Supply Voltage (VSS) ..................... –6V to GND
Total Supply Voltage (VCC to VSS)
Bipolar Operation Only ..........................................12V
Analog Input Voltage (Note 3)
Unipolar Operation ....................–0.3V to (VCC + 0.3V)
Bipolar Operation ........... (VSS – 0.3V) to (VCC + 0.3V)
Digital Input Voltage (Note 4)
Unipolar Operation ................................. –0.3V to 12V
Bipolar Operation ......................... (VSS – 0.3V) to 12V
Digital Output Voltage
Unipolar Operation ....................–0.3V to (VCC + 0.3V)
Bipolar Operation ........... (VSS – 0.3V) to (VCC + 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
T
= 150°C, θJA = 130°C/W
JMAX
ORDER PART NUMBER S8 PART MARKING
LTC1400CS8
LTC1400IS8
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.
1400
1400I
The ● denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
V
SS
I
CC
I
SS
P
D
Positive Supply Voltage (Note 6) Unipolar
Negative Supply Voltage (Note 6) Bipolar Only –2.45 –5.25 V
Positive Supply Current f
Negative Supply Current f
Power Dissipation f
The ● denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
I
IN
C
IN
2
Analog Input Range (Note 7) 4.75V ≤ VCC ≤ 5.25V (Unipolar)
4.75V ≤ VCC ≤ 5.25V, –5.25V ≤ VSS ≤ –2.45V (Bipolar)
Analog Input Leakage Current During Conversions (Hold Mode)
Analog Input Capacitance Between Conversions (Sample Mode)
During Conversions (Hold Mode)
Bipolar
= 400ksps
SAMPLE
Nap Mode
Sleep Mode
= 400ksps, VSS = –5V
SAMPLE
Nap Mode
Sleep Mode
= 400ksps
SAMPLE
Nap Mode
Sleep Mode
●
●
●
●
●
●
●
●
●
●
●
●
4.75
4.75
15
1.0
5.0
0.3
0.2
1
75
6
30
0 to 4.096
±2.048
45
5
5.25
5.25
30
3.0
20.0
0.6
0.5
5
160
20
125
±1 μA
1400fa
V
V
mA
mA
μA
mA
mA
μA
mW
mW
μW
V
V
pF
pF
LTC1400
CO VERTER CHARACTERISTICS
U
I TER AL REFERE CE CHARACTERISTICS
U U U
DY A IC ACCURACY
U
W
DIGITAL I PUTS A D DIGITAL OUTPUTS
UU
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C unless otherwise noted. With internal reference (Notes 5, 8)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Resolution (No Missing Codes)
Integral Linearity Error (Note 9)
Differential Linearity Error
Offset Error (Note 10)
Full-Scale Error ±15 LSB
Full-Scale Tempco I
OUT(REF)
= 0
The ● denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. VCC = 5V, VSS = –5V, f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
S/(N + D) Signal-to-Noise
Plus Distortion Ratio
THD Total Harmonic Distortion
Up to 5th Harmonic
Peak Harmonic or
Spurious Noise
IMD Intermodulation Distortion f
Full Power Bandwidth 4 MHz
Full Linear Bandwidth (S/(N + D) ≥ 68dB) 900 kHz
100kHz Input Signal Commercial
Industrial
200kHz Input Signal 72 dB
100kHz Input Signal
200kHz Input Signal
100kHz Input Signal
200kHz Input Signal
= 99.51kHz, f
IN1
f
= 199.12kHz, f
IN1
= 400kHz unless otherwise noted. (Note 5)
SAMPLE
= 102.44kHz
IN2
= 202.05kHz
IN2
●
12 Bits
●
●
●
●
●
●
●
●
70
69
±6
±10 ±45 ppm/°C
72 dB
–82
–80
–84
–82
–82
–70
±1 LSB
±1 LSB
LSB
±8
–76 dB
–76 dB
dB
LSB
dB
dB
dB
dB
The ● denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C unless otherwise noted. (Note 5)
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
Output Voltage I
REF
V
Output Tempco I
REF
V
Load Regulation 4.75V ≤ VCC ≤ 5.25V
REF
V
Load Regulation 0 ≤ |I
REF
V
Wake-Up Time from Sleep Mode (Note 7) C
REF
= 0 2.400 2.420 2.440 V
OUT
= 0
OUT
–5.25V ≤ VSS ≤ 0V
| ≤ 1mA 2 LSB/mA
OUT
= 10μF 4 ms
VREF
●
±10 ±45 ppm/°C
0.01
0.01
LSB/V
LSB/V
The ● denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IH
V
IL
I
IN
C
IN
V
OH
High Level Input Voltage VCC = 5.25V
Low Level Input Voltage VCC = 4.75V
Digital Input Current VIN = 0V to V
Digital Input Capacitance 5 pF
High Level Output Voltage VCC = 4.75V, IO = –10μA
VCC = 4.75V, IO = –200μA
CC
●
2.0 V
●
●
●
4.0
4.7 V
0.8 V
±10 μA
1400fa
V
3
LTC1400
DIGITAL I PUTS A D DIGITAL OUTPUTS
UU
TI I G CHARACTERISTICS
UW
The ● denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OL
Low Level Output Voltage VCC = 4.75V, IO = 160μA
VCC = 4.75V, IO = 1.6mA
I
OZ
C
OZ
I
SOURCE
I
SINK
Hi-Z Output Leakage D
Hi-Z Output Capacitance D
OUT
(Note 7) 15 pF
OUT
Output Source Current V
Output Sink Current V
V
= 0V to V
OUT
= 0V –10 mA
OUT
= V
OUT
CC
CC
The ● denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
f
SAMPLE(MAX)
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
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 VSS (ground for unipolar
mode) or above VCC, they will be clamped by internal diodes. This product
can handle input currents greater than 40mA below VSS (ground for
unipolar mode) or above VCC without latch-up.
Note 4: When these pin voltages are taken below VSS (ground for unipolar
mode), they will be clamped by internal diodes. This product can handle
input currents greater than 40mA below VSS (ground for unipolar mode)
without latch-up. These pins are not clamped to VCC.
Note 5: VCC = 5V, f
specified.
Note 6: Recommended operating conditions.
Maximum Sampling Frequency (Note 6)
Conversion Time f
Acquisition Time (Unipolar Mode)
= 6.4MHz
CLK
(Note 7)
(Bipolar Mode VSS = –5V)
CLK Frequency
CLK Pulse Width (Notes 7, 12)
Time to Wake Up from Nap Mode (Note 7) 350 ns
CLK Pulse Width to Return to Active Mode
CONV↑ to CLK↑ Setup Time
CONV↑ After Leading CLK↑
CONV Pulse Width (Note 11)
Time from CLK↑ to Sample Mode (Note 7) 80 ns
Aperture Delay of Sample-and-Hold Jitter < 50ps (Note 7)
Minimum Delay Between Conversion (Unipolar Mode)
(Bipolar Mode VSS = –5V)
Delay Time, CLK↑ to D
Delay Time, CLK↑ to D
Time from Previous Data Remains Valid After CLK↑ C
Valid C
OUT
Hi-Z C
OUT
LOAD
LOAD
LOAD
= 20pF
= 20pF
= 20pF
Minimum Time between Nap/Sleep Request to Wake Up Request (Notes 7, 12)
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).
= 400kHz, tr = tf = 5ns unless otherwise
SAMPLE
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.
●
●
0.05
0.10
10 mA
●
400 kHz
●
●
●
●
0.1 6.4 MHz
●
50 ns
●
50 ns
●
80 ns
●
●
●
●
●
●
●
●
●
0 ns
50 ns
14 25 ns
50 ns
230
200
45 65 ns
265
235
40 80 ns
40 80 ns
0.4
±10 μA
2.1 μs
300
270
385
355
1400fa
ns
ns
ns
ns
V
V
4
LTC1400
TYPICAL PERFOR A CE CHARACTERISTICS
U W
OUTPUT CODE
0
DIFFERENTIAL NONLINEARITY (LSBs)
4096
1400 TPC01
1024
2048
3072
1.00
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
512
1536
2560
3584
f
SAMPLE
= 400kHz
OUTPUT CODE
0
INTEGRAL NONLINEARITY (LSBs)
4096
1400 TPC02
1024
2048
3072
1.00
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
512
1536
2560
3584
f
SAMPLE
= 400kHz
LOAD CURRENT (mA)
–8
REFERENCE VOLTAGE (V)
–4
0
2
2.435
2,430
2.425
2.420
2.415
2.410
2.405
2.400
2.395
2.390
1400 TPC03
–6 –2
–5
–1
1
–7 –3
INPUT FREQUENCY (kHz)
80
70
60
50
40
30
20
10
0
100
1400 TPC06
10
1000
SIGNAL/(NOISE + DISTORTION) (dB)
VIN = 0dB
VIN = –20dB
VIN = –60dB
f
SAMPLE
= 400kHz
INPUT FREQUENCY (kHz)
80
70
60
50
40
30
20
10
0
100
1400 TPC07
10
1000
SIGNAL-TO-NOISE RATIO (dB)
f
SAMPLE
= 400kHz
INPUT FREQUENCY (kHz)
10
SPURIOUS-FREE DYNAMIC RANGE (dB)
0
–10
–2
0
–30
–4
0
–5
0
–60
–7
0
–80
–9
0
–100
100 1000
1400 TPC08
f
SAMPLE
= 400kHz
R
SOURCE
(Ω)
10
ACQUISITION TIME (ns)
4500
4000
3500
3000
2500
2000
1500
1000
500
0
100 1000 10000
1400 TPC05
TA = 25°C
RIPPLE FREQUENCY (kHz)
1
AMPLITUDE OF POWER SUPPLY FEEDTHROUGH (dB)
0
–1
0
–2
0
–3
0
–4
0
–5
0
–6
0
–7
0
–8
0
–9
0
–100
10 100 1000
1400 TPC07.5
f
SAMPLE
= 400kHz
VCC (V
RIPPLE
= 1mV)
VSS (V
RIPPLE
= 10mV)
TEMPERATURE (°C)
–5
0
SUPPLY CURRENT (mA)
20
15
10
5
0
–25 0
25
1400 TPC04
50 75 100 125
f
SAMPLE
= 400kHz
Differential Nonlinearity vs
Output Code
Signal-to-Noise Ratio (Without
Harmonics) vs Input Frequency
Integral Nonlinearity vs
Output Code
Peak Harmonic or Spurious Noise
vs Input Frequency
S/(N + D) vs Input Frequency
and Amplitude
Acquisition Time vs
Source Impedance
Reference Voltage vs
Load Current
Power Supply Feedthrough vs
Ripple Frequency
Supply Current vs Temperature
1400fa
5
LTC1400
U U
W
FU CTIO AL BLOCK DIAGRA
1400 BD01
12-BIT CAPACITIVE DAC COMP
SUCCESSIVE APPROXIMATION
REGISTER/PARALLEL TO
SERIAL CONVERTER
ZEROING SWITCH
CONTROL
LOGIC
2.42V REF
D
OUT
V
CC
CONV
CLK
V
REF
A
IN
C
SAMPLE
12
GND
V
SS
1400 TC01
D
OUT
D
OUT
3k
3k
C
LOAD
C
LOAD
Hi-Z TO V
OH
V
OL TO VOH
V
OH
TO Hi-Z
Hi-Z TO
V
OL
V
OH TO VOL
V
OL
TO Hi-Z
5V
TEST CIRCUITS
PI FU CTIO S
U U U
VCC (Pin 1): Positive Supply, 5V. Bypass to GND (10μF
tantalum in parallel with 0.1μF ceramic).
AIN (Pin 2): Analog Input. 0V to 4.096V (Unipolar), ±2.048V
(Bipolar).
V
(Pin 3): 2.42V Reference Output. Bypass to GND
REF
(10μF tantalum in parallel with 0.1μF ceramic).
GND (Pin 4): Ground. GND should be tied directly to an
analog ground plane.
D
(Pin 5): The A/D conversion result is shifted out
OUT
from this pin.
CLK (Pin 6): Clock. This clock synchronizes the serial data
transfer. A minimum CLK pulse of 50ns will cause the ADC
to wake up from Nap or Sleep mode.
CONV (Pin 7): Conversion Start Signal. This active high
signal starts a conversion on its rising edge. Keeping CLK
low and pulsing CONV two/four times will put the ADC
into Nap/Sleep mode.
V
(Pin 8): Negative Supply. –5V for bipolar operation.
SS
Bypass to GND with 0.1μF ceramic. VSS should be tied to
GND for unipolar operation.
6
1400fa
Loading...