LINER LTC2365IS6-TRPBF 1msps/3msps, 12-bit serial sampling adcs in tsot Datasheet

LTC2365/LTC2366
1Msps/3Msps, 12-Bit Serial
Sampling ADCs in TSOT
FEATURES
DESCRIPTION
n
The LTC®2365/LTC2366 are 1Msps/3Msps, 12-bit, sampling A/D converters that draw only 2mA and 2.6mA, respectively, from a single 3V supply. These high performance
devices include a high dynamic range sample-and-hold
and a high speed serial interface. The full scale input is
0V to VDD or VREF . Outstanding AC performance includes
72dB SINAD and –80dB THD at sample rates of 3Msps.
The serial interface provides flexible power management
and allows maximum power efficiency at low throughput
rates. These devices are available in tiny 6- and 8-lead
TSOT-23 packages.
n
n
n
n
n
n
n
n
n
n
n
12-Bit Resolution
1Msps/3Msps Sampling Rates
Low Noise: 73dB SNR
Low Power Dissipation: 6mW
Single Supply 2.35V to 3.6V Operation
No Data Latency
Sleep Mode with 0.1μA Typical Supply Current
Dedicated External Reference (TSOT23-8)
1V to 3.6V Digital Output Supply (TSOT23-8)
SPI/MICROWIRE™ Compatible Serial I/O
Guaranteed Operation from –40°C to 125°C
6- and 8-Lead TSOT-23 Packages
APPLICATIONS
n
n
n
n
n
n
n
Communication Systems
Data Acquisition Systems
Handheld Terminal Interface
Medical Imaging
Uninterrupted Power Supplies
Battery Operated Systems
Automotive
The serial interface, tiny TSOT-23 package and extremely
high sample rate-to-power ratio make the LTC2365/LTC2366
ideal for compact, low power, high speed systems.
The high impedance single-ended analog input and the
ability to operate with reduced spans (down to 1.4V full
scale) allow direct connection to sensors and transducers in
many applications, eliminating the need for gain stages.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S.
TYPICAL APPLICATION
12-Bit TSOT23-6/-8 ADC Family
DATA OUTPUT RATE
3Msps
1Msps
500ksps
250ksps
100ksps
Part Number
LTC2366
LTC2365
LTC2362
LTC2361
LTC2360
1MHz Sine Wave 8192 FFT Plot
0
Single 3V Supply, 3Msps, 12-Bit Sampling ADC
VDD = 3V
fSMPL = 3Msps
–20 f = 994kHz
IN
SINAD = 72dB
–40 THD = –80.3dB
LTC2366
ANALOG INPUT
0V TO 3V
VDD
CS
VREF
SDO
GND
SCK
AIN
OVDD
SERIAL DATA LINK TO
ASIC, PLD, MPU, DSP
OR SHIFT REGISTERS
4.7μF
23656 TA01
DIGITAL OUTPUT SUPPLY
1V TO 3.6V
MAGNITUE (dB)
3V
10μF
–60
–80
–100
–120
–140
0
250
750 1000 1250
500
INPUT FREQUENCY (kHz)
1500
23656 TA01b
23656f
1
LTC2365/LTC2366
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (VDD, OVDD).....................................4.0V
VREF and Analog Input Voltage
(Note 3).........................................–0.3V to (VDD + 0.3V)
Digital Input Voltage......................–0.3V to (VDD + 0.3V)
Digital Output Voltage ...................–0.3V to (VDD + 0.3V)
Power Dissipation ...............................................100mW
Operating Temperature Range
LTC2365C/LTC2366C ............................... 0°C to 70°C
LTC2365I/LTC2366I.............................. –40°C to 85°C
LTC2365H/LTC2366H (Note 13) ......... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
VDD 1
VREF 2
GND 3
AIN 4
8 CS
7 SCK
6 SDO
5 OVDD
VDD 1
6 CS
GND 2
5 SDO
AIN 3
4 SCK
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 250°C/W
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 250°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2366CTS8#TRMPBF
LTC2366CTS8#TRPBF
LTCYZ
8-lead Plastic TSOT-23
0°C to 70°C
LTC2366ITS8#TRMPBF
LTC2366ITS8#TRPBF
LTCYZ
8-lead Plastic TSOT-23
–40°C to 85°C
LTC2366HTS8#TRMPBF
LTC2366HTS8#TRPBF
LTCYZ
8-lead Plastic TSOT-23
–40°C to 125°C
LTC2366CS6#TRMPBF
LTC2366CS6#TRPBF
LTCXK
6-lead Plastic TSOT-23
0°C to 70°C
LTC2366IS6#TRMPBF
LTC2366IS6#TRPBF
LTCXK
6-lead Plastic TSOT-23
–40°C to 85°C
LTC2366HS6#TRMPBF
LTC2366HS6#TRPBF
LTCXK
6-lead Plastic TSOT-23
–40°C to 125°C
LTC2365CTS8#TRMPBF
LTC2365CTS8#TRPBF
LTDCB
8-lead Plastic TSOT-23
0°C to 70°C
LTC2365ITS8#TRMPBF
LTC2365ITS8#TRPBF
LTDCB
8-lead Plastic TSOT-23
–40°C to 85°C
LTC2365HTS8#TRMPBF
LTC2365HTS8#TRPBF
LTDCB
8-lead Plastic TSOT-23
–40°C to 125°C
LTC2365CS6#TRMPBF
LTC2365CS6#TRPBF
LTDCC
6-lead Plastic TSOT-23
0°C to 70°C
LTC2365IS6#TRMPBF
LTC2365IS6#TRPBF
LTDCC
6-lead Plastic TSOT-23
–40°C to 85°C
LTC2365HS6#TRMPBF
LTC2365HS6#TRPBF
LTDCC
6-lead Plastic TSOT-23
–40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
23656f
2
LTC2365/LTC2366
CONVERTER CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 4)
LTC2365
PARAMETER
CONDITIONS
MIN
TYP
LTC2366
MAX
MIN
TYP
MAX
UNITS
Resolution (No Missing Codes)
l
Integral Linearity Error
(Note 5, 6)
l
±0.25
±1
±0.25
±1
LSB
Differential Linearity Error
(Note 6)
l
±0.25
±1
±0.25
±1
LSB
Transition Noise
(Note 7)
Offset Error
(Note 6)
l
2
±3.5
2
±3.5
LSB
Gain Error
(Note 6)
l
1
±2
1
±2
LSB
S6 Package (Note 6)
TS8 Package (Note 6)
l
l
2
3
±3.5
±4.5
2
3
±3.5
±4.5
LSB
LSB
Total Unadjusted Error
12
12
Bits
0.34
0.34
LSBRMS
ANALOG INPUTS The l denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN
Analog Input Voltage
S6 Package
TS8 Package
l
l
IIN
Analog Input Leakage Current
CS = High
l
CIN
Analog Input Capacitance
Between Conversions
During Conversions
VREF
Reference Input Voltage
TS8 Package
l
IREF
Reference Input Leakage Current
TS8 Package
l
CREF
Reference Input Capacitance
TS8 Package
tAP
Sample-and-Hold Aperture Delay Time
tJITTER
Sample-and-Hold Aperture Delay Time Jitter
TYP
MAX
–0.05
–0.05
UNITS
VDD + 0.05
VREF + 0.05
V
V
±1
μA
20
4
pF
pF
1.4
VDD + 0.05
V
±1
μA
4
pF
1
ns
0.3
ns
DYNAMIC ACCURACY The l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. (Note 4)
LTC2365
SYMBOL
PARAMETER
CONDITIONS
MIN
SINAD
Signal-to-(Noise + Distortion) Ratio fIN = 1MHz
l
SNR
Signal-to-Noise Ratio
fIN = 1MHz
l
l
LTC2366
TYP MAX MIN
TYP MAX UNITS
68
72
68
71
dB
70
73
69
72
dB
THD
Total Harmonic Distortion
fIN = 1MHz
SFDR
Spurious Free Dynamic Range
fIN = 1MHz
–86
87
–72
–80
–72
dB
IMD
Intermodulation Distortion
fIN1 = 0.97MHz, fIN2 = 1MHz for LTC2366
fIN1 = 97kHz, fIN2 = 100kHz for LTC2365
–76
Full Power Bandwidth
At 3dB
At 0.1dB
30
5
50
8
MHz
MHz
Full Linear Bandwidth
SINAD ≥ 68dB
2
2.5
MHz
82
–71.5
dB
23656f
3
LTC2365/LTC2366
DIGITAL INPUTS AND DIGITAL OUTPUTS
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
VIH
High Level Input Voltage
2.7V < VDD ≤ 3.6V
2.35V ≤ VDD ≤ 2.7V
l
l
VIL
Low Level Input Voltage
2.7V < VDD ≤ 3.6V
2.35V ≤ VDD ≤ 2.7V
l
l
0.8
0.7
V
V
IIH
High Level Input Current
VIN = VDD
l
2.5
μA
IIL
Low Level Input Current
VIN = 0V
l
–2.5
μA
CIN
Digital Input Capacitance
VOH
High Level Output Voltage
VDD = 2.35V to 3.6V, ISOURCE = 200μA
l
VOL
Low Level Output Voltage
VDD = 2.35V to 3.6V, ISINK = 200μA
l
0.2
V
IOZ
Hi-Z Output Leakage
CS = VDD
l
±3
μA
COZ
Hi-Z Output Capacitance
CS = VDD
4
ISOURCE
Output Source Current
VOUT = 0V
–10
mA
ISINK
Output Sink Current
VOUT = VDD
10
mA
2
1.7
UNITS
V
V
2
pF
VDD –0.2
V
pF
POWER REQUIREMENT
SYMBOL
PARAMETER
MIN
TYP
MAX
VDD
Supply Voltage
l
2.35
3.0
3.6
V
OVDD
Digital Output Supply Voltage
l
1
3.6
V
IDD
Supply Current, Static Mode
Operational Mode, LTC2366
Operational Mode, LTC2365
Sleep Mode
Sleep Mode
CS = 0V, SCK = 0V or VDD
fSMPL = 3Msps
fSMPL = 1Msps
–40°C to +85°C
+85°C to +125°C
l
l
l
l
4
3.5
2
5
mA
mA
mA
μA
μA
Power Dissipation, Static Mode
Operational Mode, LTC2366
Operational Mode, LTC2365
Sleep Mode
Sleep Mode
CS = 0V, SCK = 0V or VDD
fSMPL = 3Msps
fSMPL = 1Msps
–40°C to +85°C
+85°C to +125°C
l
l
l
l
3.6
14.4
12.6
7.2
18
mW
mW
mW
μW
μW
PD
CONDITIONS
1
2.6
2
0.1
7.8
6
0.3
UNITS
23656f
4
LTC2365/LTC2366
TIMING CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 4)
LTC2365
MIN
PARAMETER
CONDITIONS
fSMPL(MAX)
Maximum Sampling Frequency
(Notes 8, 9)
l
1
fSCK
Shift Clock Frequency
(Notes 8, 9, 10)
l
0.5
tSCK
Shift Clock Period
l
62.5
tTHROUGHPUT
Minimum Throughput Time, tACQ + tCONV
l
tACQ
Acquisition Time
l
181.5
56
ns
tCONV
Conversion Time
l
818.5
277
ns
tQUIET
SDO Hi-Z State to CS ↓
l
4
4
ns
t1
Minimum Positive or Negative CS Pulse Width (Notes 8)
l
4
t2
SCK↓ Setup Time After CS ↓
(Notes 8)
l
6
t3
SDO Enabled Time After CS ↓
(Notes 9, 11, 12)
l
t4
SDO Data Valid Access Time After SCK↓
(Notes 8, 9, 11)
l
t5
SCK Low Time
t6
SCK High Time
t7
SDO Data Valid Hold Time After SCK↓
(Notes 8, 9, 11)
t8
SDO Into Hi-Z State Time After SCK↓
t9
tPOWER-UP
(Notes 8, 9)
TYP
LTC2366
SYMBOL
MAX
MIN
TYP
MAX UNITS
3
MHz
16
0.5
48
2000
20.8
2000
ns
333
ns
1000
4
2000
6
MHz
ns
2000
ns
4
4
ns
15
15
ns
l
40%
40%
tSCK
l
40%
40%
tSCK
l
5
5
(Notes 9, 12)
l
5
SDO Into Hi-Z State Time After CS ↑
(Notes 9, 12)
l
Power-up Time from Sleep Mode
See Sleep Mode section
l
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 this pin, AIN, is taken below GND or above VDD, it will be
clamped by internal diodes. These products can handle input currents
greater than 100mA below GND or above VDD without latchup.
Note 4: VDD = OVDD = VREF = 2.35V to 3.6V, fSMPL = fSMPL(MAX) and fSCK =
fSCK(MAX) unless otherwise specified.
Note 5: Integral linearity 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.
30
5
ns
14
ns
4.2
4.2
ns
1000
333
ns
Note 6: Linearity, offset and gain specifications apply for a single-ended
AIN input with respect to GND.
Note 7: Typical RMS noise at code transitions.
Note 8: Guaranteed by characterization. All input signals are specified with
tr = tf = 2ns (10% to 90% of VDD) and timed from a voltage level of 1.6V.
Note 9: All timing specifications given are with a 10pF capacitance load.
With a capacitance load greater than this value, a digital buffer or latch
must be used.
Note 10: Minimum fSCK at which specifications are guaranteed.
Note 11: The time required for the output to cross the VIH or VIL voltage.
Note 12: Guaranteed by design, not subject to test.
Note 13: High temperatures degrade operating lifetimes. Operating lifetime
is derated at temperatures greater than 105°C.
23656f
5
LTC2365/LTC2366
TYPICAL PERFORMANCE CHARACTERISTICS
Integral Nonlinearity
vs Output Code
1.0
1.0
Integral and Differential
Nonlinearity vs Supply Voltage
1.0
VDD = 3V
0.8
0.8
0.6
0.6
0.4
0.4
0.4
0.2
0.2
0
–0.2
INL AND DNL (LSB)
0.6
DNL (LSB)
INL (LSB)
Differential Nonlinearity
vs Output Code
VDD = 3V
0.8
TA = 25°C, VDD = OVDD = VREF (LTC2365, Note 4)
0
–0.2
0.2
–0.2
–0.4
–0.6
–0.6
–0.6
–0.8
–0.8
–0.8
–1.0
–1.0
1024
2048
3072
OUTPUT CODE
4096
1024
0
2048
3072
OUTPUT CODE
23656 G01
MIN INL
–0.4
–1.0
2.1
4096
SNR vs Input Frequency
VDD = 3V
8000
73.3
6000
73.1
SINAD vs Input Frequency
VDD = 3.6V
73.0
SINAD (dB)
SNR (dB)
COUNT
72.8
VDD = 3V
72.9
VDD = 3V
72.6
VDD = 2.35V
72.4
VDD = 2.35V
72.7
2000
2045
2046
2047 2048
CODE
2049
72.2
72.5
100
2050
INPUT FREQUENCY (kHz)
461kHz Sine Wave 8192 FFT Plot
0
VDD = 3V
fSMPL = 1Msps
fIN = 1MHz
–79
VDD = 3V
–85
MAGNITUDE (dB)
THD (dB)
THD (dB)
–83
–86
23656 G06
THD vs Input Resistance
–78
RIN = 10Ω
fSMPL = 1Msps
–84
1000
INPUT FREQUENCY (kHz)
23656 G05
THD vs Input Frequency
–82
72.0
100
1000
23656 G04
–81
3.6
73.2
VDD = 3.6V
0
3.0
3.3
2.7
SUPPLY VOLTAGE (V)
23656 G03
73.5
4000
2.4
23656 G02
Histogram for 16384 Conversions
10000
MAX DNL
MIN DNL
0
–0.4
0
MAX INL
–80
–81
VDD = 2.35V
VDD = 3V
fSMPL = 1Msps
–20 f = 461kHz
IN
SINAD = 72.8dB
–40 THD = –86.1dB
–60
–80
–100
VDD = 3.6V
–82
–87
–120
–88
100
1000
INPUT FREQUENCY (kHz)
23656 G07
–83
–140
0
50
25
75
INPUT RESISTANCE (Ω)
100
23656 G08
0
100
200
300
400
INPUT FREQUENCY (kHz)
500
23656 G09
23656f
6
LTC2365/LTC2366
TYPICAL PERFORMANCE CHARACTERISTICS
Differential Nonlinearity
vs Output Code
Integral Nonlinearity
vs Output Code
1.0
1.0
VDD = 3V
0.8
Integral and Differential
Nonlinearity vs Supply Voltage
1.0
VDD = 3V
0.8
0.8
0.6
0.4
0.4
0.4
0.2
0.2
0
–0.2
INL AND DNL (LSB)
0.6
DNL (LSB)
0.6
INL (LSB)
TA = 25°C, VDD = OVDD = VREF (LTC2366, Note 4)
0
–0.2
0
–0.4
–0.6
–0.6
–0.8
–0.8
–0.8
–1.0
–1.0
2048
3072
OUTPUT CODE
4096
1024
0
2048
3072
OUTPUT CODE
23656 G10
–0.4
MIN DNL
–1.0
2.1
4096
SNR vs Input Frequency
VDD = 3V
8000
73.0
6000
72.8
SINAD vs Input Frequency
VDD = 3.6V
72.5
VDD = 2.35V
SINAD (dB)
72.0
SNR (dB)
3.6
73.0
VDD = 3.6V
COUNT
3.0
3.3
2.7
SUPPLY VOLTAGE (V)
23656 G12
73.2
4000
2.4
23656 G11
Histogram for 16384 Conversions
10000
MIN INL
–0.2
–0.4
1024
MAX DNL
0.2
–0.6
0
MAX INL
VDD = 3V
72.6
VDD = 3V
71.5
71.0
VDD = 2.35V
72.4
2000
0
2045
2046
2047 2048
CODE
2049
70.5
72.2
100
2050
THD vs Input Resistance
RIN = 10Ω
fSMPL = 3Msps
1MHz Sine Wave 8192 FFT Plot
0
–64
VDD = 3V
fSMPL = 3Msps
–20 f = 994kHz
IN
SINAD = 72dB
–40 THD = –80.3dB
VDD = 3V
fSMPL = 3Msps
fIN = 1.5MHz
–66
-76
–80
VDD = 3.6V
–82
–84
VDD = 3V
–86
MAGNITUE (dB)
–68
–78
THD (dB)
THD (dB)
23656 G15
23656 G14
THD vs Input Frequency
–74
1000 1500
INPUT FREQUENCY (kHz)
INPUT FREQUENCY (kHz)
23656 G13
–72
70.0
100
1000 1500
–70
–72
–60
–80
–74
–100
–76
–120
VDD = 2.35V
–88
100
1000 1500
INPUT FREQUENCY (kHz)
23656 G16
–140
–78
0
25
50
75
INPUT RESISTANCE (Ω)
100
23656 G17
0
250
750 1000 1250
500
INPUT FREQUENCY (kHz)
1500
23656 G18
23656f
7
LTC2365/LTC2366
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VDD = OVDD = VREF
(LTC2365/LTC2366, Note 4)
Integral and Differential
Nonlinearity vs Reference
Voltage (TS8 Package)
Reference Current vs SCK
Frequency (TS8 Package)
Supply Current vs SCK Frequency
3.0
250
1.0
16 SCKS PER CONVERSION
2.5
REFERENCE CURRENT (μA)
VDD = 3.6V
IDD (mA)
2.0
1.5
VDD = 3V
VDD = 2.35V
1.0
0.5
NONLINEARITY ERROR (LSB)
0.8
200
150
VDD = 3V
100
VDD = 3.6V
50
VDD = 2.35V
0
0
10
0
50
20
30
40
SCK FREQUENCY (MHz)
5
0
LTC2366, VDD = 3.6V
MAX DNL
MAX INL
–0.2
MIN DNL
–0.4
–0.6
MIN DNL
–0.2
–0.4
MIN INL
–0.6
–1.0
0.6
1.2
2.4
3.0
1.8
REFERENCE VOLTAGE (V)
3.6
23656 G21
VDD = 3V
LTC2366
0.4
0
MAX INL
0
0
0.6
0.2
0.2
Input Power Bandwidth
2
MAGNITUDE (dB)
NONLINEARITY ERROR (LSB)
0.8
MAX DNL
0.4
23656 G20
Integral and Differential
Nonlinearity vs Reference
Voltage (TS8 Package)
1.0
0.6
–0.8
10 15 20 25 30 35 40 45 50
SCK FREQUENCY (MHz)
23656 G19
LTC2365, VDD = 3.6V
MIN INL
–2
–4
LTC2365
–6
–8
–0.8
–1.0
0.6
–10
1.2
2.4
3.0
1.8
REFERENCE VOLTAGE (V)
3.6
23656 G22
1
10
INPUT FREQUENCY (MHz)
100
23656 G23
23656f
8
LTC2365/LTC2366
PIN FUNCTIONS
LTC2365/LTC2366 (S6 Package)
LTC2365/LTC2366 (TS8 Package)
VDD (Pin 1): Positive Supply. The VDD range is 2.35V to
3.6V. VDD also defines the input span of the ADC, 0V to
VDD. Bypass to GND and to a solid ground plane with a
10μF ceramic capacitor (or 10μF tantalum in parallel with
0.1μF ceramic).
VDD (Pin 1): Positive Supply. The VDD range is 2.35V to
3.6V. Bypass to GND and to a solid ground plane with a
10μF ceramic capacitor (or 10μF tantalum in parallel with
0.1μF ceramic).
GND (Pin 2): Ground. The GND pin must be tied directly
to a solid ground plane.
AIN (Pin 3): Analog Input. AIN is a single-ended input with
respect to GND with a range from 0V to VDD.
SCK (Pin 4): Shift Clock Input. The SCK serial clock advances the conversion process. SDO data transitions on
the falling edge of SCK.
SDO (Pin 5): Three-state Serial Data Output. The A/D
conversion result is shifted out on SDO as a serial data
stream with MSB first. The data stream consists of two
leading zeros followed by 12 bits of conversion data and
two trailing zeros.
CS (Pin 6): Chip Select Input. This active low signal starts
a conversion on the falling edge and frames the serial
data transfer.
VREF (Pin 2): Reference Input. VREF defines the input
span of the ADC, 0V to VREF and the VREF range is 1.4V
to VDD. Bypass to GND and to a solid ground plane with
a 4.7μF ceramic capacitor (or 4.7μF tantalum in parallel
with 0.1μF ceramic).
GND (Pin 3): Ground. The GND pin must be tied directly
to a solid ground plane.
AIN (Pin 4): Analog Input. AIN is a single-ended input with
respect to GND with a range from 0V to VREF.
OVDD (Pin 5): Output Driver Supply for SDO. The OVDD
range is 1V to 3.6V. Bypass to GND and to a solid ground
plane with a 4.7μF ceramic capacitor (or 4.7μF tantalum
in parallel with 0.1μF ceramic).
SDO (Pin 6): Three-state Serial Data Output. The A/D
conversion result is shifted out on SDO as a serial data
stream with MSB first. The data stream consists of two
leading zeros followed by 12 bits of conversion data and
two trailing zeros.
SCK (Pin 7): Shift Clock Input. The SCK serial clock advances the conversion process. SDO data transitions on
the falling edge of SCK.
CS (Pin 8): Chip Select Input. This active low signal starts
a conversion on the falling edge and frames the serial
data transfer.
23656f
9
LTC2365/LTC2366
BLOCK DIAGRAM
4.7μF
10μF
+
+
OVDD
VDD
ANALOG
INPUT RANGE
OV TO VREF
1
5
12-BIT ADC
THREESTATE
SERIAL
OUTPUT
PORT
AIN
4
+
S&H
–
6
SDO
7
SCK
8
CS
VREF
2
+
4.7μF
TIMING
LOGIC
GND
3
TS8 PACKAGE
23656 BD
TIMING DIAGRAMS
t8
SCK
1.6V
Hi-Z
SDO
23656 TD01
Figure 1. SDO Into Hi-Z State After SCK Falling Edge
t7
SCK
SDO
1.6V
VIH
VIL
23656 TD02
Figure 2. SDO Data Valid Hold Time After SCK Falling Edge
t4
SCK
SDO
1.6V
VOH
VOL
23656 TD03
Figure 3. SDO Data Valid Access Time After SCK Falling Edge
23656f
10
LTC2365/LTC2366
APPLICATIONS INFORMATION
DC PERFORMANCE
DYNAMIC PERFORMANCE
The noise of an ADC can be evaluated in two ways: signalto-noise ratio (SNR) in the frequency domain and histogram
in the time domain. The LTC2365/LTC2366 excel in both.
Figures 5 and 6 demonstrate that the LTC2365/LTC2366
have an SNR of over 72dB. The noise in the time domain
histogram is the transition noise associated with a 12-bit
resolution ADC which can be measured with a fixed DC signal
applied to the input of the ADC. The resulting output codes
are collected over a large number of conversions. The
shape of the distribution of codes will give an indication
of the magnitude of the transition noise. In Figure 4, the
distribution of output codes is shown for a DC input that
has been digitized 16384 times. The distribution is Gaussian and the RMS code transition is about 0.34LSB. This
corresponds to a noise level of 72.7dB relative to a full
scale of 3V.
The LTC2365/LTC2366 have excellent high speed sampling
capability. Fast fourier transform (FFT) test techniques are
used to test the ADC’s frequency response, distortion and
noise at the rated throughput. By applying a low distortion
sine wave and analyzing the digital output using an FFT
algorithm, the ADC’s spectral content can be examined for
frequencies outside the fundamental. Figures 5 and 6 show
typical LTC2365 and LTC2366 FFT plots respectively.
MAGNITUDE (dB)
0
VDD = 3V
fSMPL = 1Msps
–20 fIN = 461kHz
SINAD = 72.8dB
–40 THD = –86.1dB
–60
–80
–100
–120
–140
0
100
200
300
400
INPUT FREQUENCY (kHz)
500
23656 F05
Figure 5. LTC2365 FFT Plot
10000
0
VDD = 3V
fSMPL = 3Msps
–20 f = 994kHz
IN
SINAD = 72dB
–40 THD = –80.3dB
VDD = 3V
MAGNITUE (dB)
COUNT
8000
6000
4000
–60
–80
–100
2000
0
–120
–140
2045
2046
2047 2048
CODE
2049
2050
0
250
750 1000 1250
500
INPUT FREQUENCY (kHz)
23656 F06
23656 F04
Figure 4. Histogram for 16384 Conversions
1500
Figure 6. LTC2366 FFT Plot
23656f
11
LTC2365/LTC2366
APPLICATIONS INFORMATION
Signal-to-Noise plus Distortion Ratio
The signal-to-noise plus distortion ratio (SINAD) is the
ratio between the RMS amplitude of the fundamental input
frequency to the RMS amplitude of all other frequency
components at the A/D output. The output is band limited
to frequencies from above DC and below half the sampling
frequency. Figure 6 shows a typical FFT with a 3MHz sampling rate and a 1MHz input. The dynamic performance
is excellent for input frequencies up to and beyond the
Nyquist frequency of 1.5MHz.
Effective Number of Bits
sampling rate of 3MHz, the LTC2366 maintains ENOB
above 11 bits up to the Nyquist input frequency of 1.5MHz
(refer to Figure 7).
Total Harmonic Distortion
The total harmonic distortion (THD) is the ratio of the RMS
sum of all harmonics of the input signal to the fundamental
itself. The out-of-band harmonics alias into the frequency
band between DC and half the sampling frequency. THD
is expressed as:
THD = 20log
The effective number of bits (ENOB) is a measurement
of the resolution of an ADC and is directly related to
SINAD by the equation:
ENOB = (SINAD – 1.76)/6.02
where ENOB is the effective number of bits of resolution and SINAD is expressed in dB. At the maximum
73.0
V2 2 + V3 2 + V4 2 + ...Vn 2
V1
where V1 is the RMS amplitude of the fundamental
frequency and V2 through Vn are the amplitudes of the
second through nth harmonics. THD versus Input Frequency is shown in Figure 8. The LTC2366 has excellent
distortion performance up to the Nyquist frequency and
beyond.
11.83
–72
VDD = 3.6V
RIN = 10Ω
–74
72.5
–76
11.67
VDD = 3V
71.0
11.50
THD (dB)
71.5
VDD = 2.35V
ENOB
SINAD (dB)
72.0
–78
–80
VDD = 3.6V
–82
–84
70.5
VDD = 3V
–86
VDD = 2.35V
11.34
1000 1500
70.0
100
INPUT FREQUENCY (kHz)
–88
100
1000 1500
INPUT FREQUENCY (kHz)
23656 F07
Figure 7. LTC2366 ENOB and SINAD vs Input Frequency
23656 F08
Figure 8. LTC2366 Distortion vs Input Frequency
23656f
12
LTC2365/LTC2366
APPLICATIONS INFORMATION
Intermodulation Distortion
Peak Harmonic or Spurious Noise
If the ADC input signal consists of more than one spectral
component, the ADC transfer function nonlinearity can
produce intermoduation distortion (IMD) in addition to
THD. IMD is the change in one sinusoidal input caused
by the presence of another sinusoidal input at a different
frequency.
The peak harmonic or spurious noise is the largest spectral
component excluding the input signal and DC. This value
is expressed in decibels relative to the RMS value of a
full-scale input signal.
If two pure sine waves of frequencies fa and fb are applied
to the ADC input, nonlinearities in the ADC transfer function
can create distortion products at the sum and difference
frequencies of mfa±nfb, where m and n = 0, 1, 2, 3, etc.
For example, the 2nd order IMD terms include (fa ± fb).
If the two input sine waves are equal in magnitude, the
value (in decibels) of the 2nd order IMD products can be
expressed by the following formula:
Amplitude at (fa ± fb )
IMD(fa ± fb ) = 20log
Amplitude at fa
The full-power bandwidth is that input frequency at which
the amplitude of reconstructed fundamental is reduced by
3dB for full-scale input signal.
Full-Power and Full-Linear Bandwidth
The full-linear bandwidth is the input frequency at which
the SINAD has dropped to 68dB (11 effective bits). The
LTC2365/LTC2366 have been designed to optimize input
bandwidth, allowing the ADC to undersample input signals with frequencies above the converter’s Nyquist Frequency. The noise floor stays very low at high frequencies;
SINAD becomes dominated by distortion at frequencies
far beyond Nyquist.
The LTC2365/LTC2366 have good IMD as shown in Figure
9a and Figure 9b respectively.
0
VDD = 3V
= 1Msps
f
–20 fSMPL
b = 396kHz
fb = 424kHz
–40 IMD = –73.5dB
VDD = 3V
fSMPL = 3Msps
–20 f = 935kHz
a
fb = 1.045kHz
–40 IMD = –71.5dB
MAGNITUE (dB)
MAGNITUDE (dB)
0
–60
–80
–60
–80
–100
–100
–120
–120
–140
–140
0
50 100 150 200 250 300 350 400 450 500
INPUT FREQUENCY (kHz)
23656 F09a
Figure 9a. LTC2365 Intermodulation Distortion Plot
0
250
750 1000 1250
500
INPUT FREQUENCY (kHz)
1500
23656 F09b
Figure 9b. LTC2366 Intermodulation Distortion Plot
23656f
13
LTC2365/LTC2366
APPLICATIONS INFORMATION
OVERVIEW
Figures 11 and 12 detail the timing diagrams of conversion
cycles in 14 and 16 SCK cycles respectively.
The LTC2365/LTC2366 use a successive approximation
algorithm and internal sample-and-hold circuit to convert an
analog signal to a 12-bit serial output. Both devices operate
from a single 2.35V to 3.6V supply. The LTC2366 samples
at a rate of 3Msps with a 48MHz clock while the LTC2365
samples at a rate of 1Msps with a 16MHz clock.
Data Transfer
A falling CS edge starts a conversion and frames the serial data transfer. SCK provides the conversion clock and
controls the data transfer during the conversion.
CS going low clocks out the first leading zero and subsequent SCK falling edges clock out the remaining data,
beginning with the second leading zero. (Therefore, the
first SCK falling edge captures the first leading zero and
clocks out the second leading zero). The timing diagram
in Figure 12 shows that the final bit in the data transfer is
valid on the 16th falling edge, since it is clocked out on
the previous 15th falling edge.
The LTC2365/LTC2366 contain a 12-bit, switched-capacitor
ADC, a sample-and-hold, and a serial interface (see Block
Diagram) and are available in tiny 6- and 8-lead TSOT-23
packages. The devices provide sleep mode control through
the serial interface to save power during inactive periods
(see the SLEEP MODE section).
The S6 package of the LTC2365/LTC2366 uses VDD as the
reference and has an analog input range of 0V to VDD. The
ADC samples the analog input with respect to GND and
outputs the result through the serial interface.
In applications with a slower SCK, it is possible to capture
data on each SCK rising edge. In such cases, the first falling edge of SCK clocks out the second leading zero and
can be captured on the first rising edge. However, the first
leading zero clocked out when CS goes low is missed as
shown in Figures 11 and 12. In Figure 12, the 15th falling
edge of SCK clocks out the last bit and can be captured
on the 15th rising SCK edge.
The TS8 package provides two additional pins: a reference
input pin, VREF, and an output supply pin, OVDD. The ADC
can operate with reduced spans down to 1.4V and achieve
342μV resolution. OVDD controls the output swing of the
digital output pin, SDO, and allows the device to communicate with 1.8V, 2.5V or 3V digital systems.
If CS goes low while SCK is low, then CS clocks out the
first leading zero and can be captured on the SCK rising
edge. The next SCK falling edge clocks out the second
leading zero and can be captured on the following rising
edge as shown in in Figure 10.
SERIAL INTERFACE
The LTC2365/LTC2366 communicate with microcontrollers,
DSPs and other external circuitry via a 3-wire interface.
Figure 10 shows the serial interface timing diagram, while
t1
CS
tCONV
t2
t6
SCK
2
1
3
4
t3
SDO
ZERO
5
t4
ZERO
B11
B10
B9
13
14
B1
15
16
t5
t7
t8
tQUIET
B0
ZERO
ZERO
Hi-Z STATE
(MSB)
13tSCK
tACQ
tTHROUGHPUT
23656 F10
Figure 10. LTC2365/LTC2366 Serial Interface Timing Diagram
23656f
14
LTC2365/LTC2366
APPLICATIONS INFORMATION
Achieving 3Msps Sample Rate with LTC2366
Serial Data Output (SDO)
CS going low places the sample-and-hold into hold mode
and starts a conversion. The LTC2365/LTC2366 require
at least 14 SCK cycles to finish the conversion. The
conversion terminates after the 13th falling SCK edge,
which clocks out B0. The 14th falling SCK edge places
the sample-and-hold back into sample mode.
The SDO output remains in the high impedance state while
CS is high. The falling edge of CS starts the conversion
and enables SDO. The A/D conversion result is shifted out
on the SDO pin as a serial data stream with the MSB first.
The data stream consists of two leading zeros followed
by 12 bits of conversion data and two trailing zeros. The
SDO output returns to the high impedance state at the
16th falling edge of SCK or sooner by bringing ⎯C⎯S high
before the 16th falling edge of SCK.
Ignoring the last two trailing zeros, the user can bring CS
high after the 14th falling SCK edge. The user can also
keep the last two trailing zeros by bringing CS high right
after the 16th falling SCK. In both cases, a sample rate
of 3Msps can be achieved by using a 48MHz SCK clock
on the LTC2366, where tTHROUGHPUT is 333ns.
The output swing on the SDO pin is controlled by the VDD
pin voltage in the S6 package and by the OVDD pin voltage
in the TS8 package.
t1
CS
tACQ
tCONV
t6
t2
SCK
1
2
3
4
5
t4
t3
SDO
Z
ZERO
B11
B10
13
14
t5
t7
B9
B1
t9
tQUIET
B0
Hi-Z STATE
(MSB)
tTHROUGHPUT
23656 F11
Figure 11. LTC2365/LTC2366 Serial Interface Timing Diagram for 14 SCK Cycles
t1
CS
tACQ
tCONV
t6
t2
SCK
1
2
3
4
t4
t3
SDO
Z
ZERO
5
B11
B10
B9
13
14
t7
B1
15
16
t5
B0
t8 OR t9
tQUIET
ZERO
ZERO
Hi-Z STATE
(MSB)
tTHROUGHPUT
23656 F12
Figure 12. LTC2365/LTC2366 Serial Interface Timing Diagram for 16 SCK Cycles
23656f
15
LTC2365/LTC2366
APPLICATIONS INFORMATION
SLEEP MODE
Entering Sleep Mode
The LTC2365/LTC2366 provide a sleep mode to conserve
power during inactive periods. Upon power-up, holding
CS high initializes the ADC to sleep mode. In sleep mode,
all bias circuitry is shut down and only leakage currents
remain (0.1μA typ).
The ADC achieves the fastest sampling rate in operational
mode (full power-up). The device can also be put into sleep
mode for power savings during inactive periods. To force
the LTC2365/LTC2366 into sleep mode, the user can interrupt the conversion process by bringing CS high between
the 2nd and 10th falling edges of SCK (see Figures 13 and
14). If CS is brought high after the 10th falling edge and
before the 16th falling edge, the device remains powered
up, but the conversion is terminated and SDO returns to
the high impedance state.
CS
1
2
10
12
14
16
SCK
SDO
VALID DATA
23656 F13
Figure 13. LTC2365/LTC2366 Operational Mode
CS
1
2
10
12
14
16
SCK
SDO
Hi-Z STATE
23656 F14
Figure 14. LTC2365/LTC2366 Entering Sleep Mode
23656f
16
LTC2365/LTC2366
APPLICATIONS INFORMATION
Exiting Sleep Mode and Power-Up Time
POWER VERSUS SAMPLING RATE
To exit sleep mode, pull CS low and perform a dummy
conversion. The LTC2365/LTC2366 device power up completely after the 16th falling edge of SCK. After powering
up, the ADC can continuously acquire an input signal
and perform conversions as described in the SERIAL
INTERFACE section (see Figure 15). The wake-up time is
333ns for the LTC2366 with a 48MHz SCK and 1μs for the
LTC2365 with a 16MHz SCK.
Figure 16 shows the power consumption of the LTC2365/
LTC2366 in operational mode. By taking the ADC into sleep
mode when not performing a conversion, the average
power consumption of the ADC decreases as the sampling
rate decreases. Figure 17 shows the power consumption
versus sampling rate with the device in sleep mode when
not performing a conversion.
The sample-and-hold is in hold mode while the device is in
sleep mode. The ADC returns to sample mode after the 1st
falling edge of SCK during power-up (see Figure 15).
THE DEVICE BEGINS
TO POWER UP
THE DEVICE BEGINS
TO ACQUIRE INPUT
THE DEVICE IS FULLY
POWERED UP AND READY
TO PERFORM CONVERSION
tPOWER-UP
CS
1
2
10
12
14
16
1 2
10
12
14
16
SCK
SDO
INVALID DATA
VALID DATA
23656 F15
Figure 15. LTC2365/LTC2366 Exiting Sleep Mode
7.5
8
VDD = 3V
fSCK = VARIABLE
16 SCKS PER CONVERSION
7.0
VDD = 3V
7 fSCK = 48MHz
6
6.0
POWER (mW)
POWER (mW)
6.5
5.5
5.0
4.5
5
4
3
4.0
2
3.5
1
3.0
0
0
500
1000 1500 2000
SAMPLE RATE (ksps)
2500
3000
23656 F16
Figure 16. Power Consumption vs Sample Rate while
the Device Remains Powered Up Continuously
0
500
250
750
SAMPLE RATE (ksps)
1000
23656 F17
Figure 17. Power Consumption vs Sample Rate while the Device
Enters Sleep Mode when not Performing Conversions
23656f
17
LTC2365/LTC2366
APPLICATIONS INFORMATION
SINGLE-ENDED ANALOG INPUT
Choosing an Input Amplifier
Driving the Analog Input
Choosing an input amplifier is easy if a few requirements
are taken into consideration. First, to limit the magnitude
of the voltage spike seen by amplifier from charging the
sampling capacitor, choose an amplifier that has a low
output impedance (<100Ω) at the closed-loop bandwidth
frequency. For example, if an amplifier is used in a gain
of 1 and has a unitygain bandwidth of 50MHz, then the
output impedance at 50MHz must be less than 100Ω. The
second requirement is that the closed-loop bandwidth must
be greater than 40MHz to ensure adequate small signal
settling for full throughput rate. If slower op amps are
used, more time for settling can be provided by increasing the time between conversions. The best choice for an
op amp to drive the LTC2365/LTC2366 will depend on the
application. Generally, applications fall into two categories:
AC applications where dynamic specifications are most
critical and time domain applications where DC accuracy
and settling time are most critical. The following list is a
summary of the op amps that are suitable for driving the
LTC2365/LTC2366. (More detailed information is available
on the Linear Technology website at www.linear.com.)
The analog input of the LTC2365/LTC2366 is easy to drive.
The input draws only one small current spike while charging the sample-and-hold capacitor at the end of conversion. During the conversion, the analog input draws only
a small leakage current. If the source impedance of the
driving circuit is low, then the input of the LTC2365/LT2366
can be driven directly. As source impedance increases,
so will acquisition time. For minimum acquisition time
with high source impedance, a buffer amplifier should be
used. The main requirement is that the amplifier driving
the analog input must settle after the small current spike
before the next conversion starts (settling time must be
less than 56ns for full throughput rate). While choosing
an input amplifier, also keep in mind the amount of noise
and harmonic distortion the amplifier contributes.
23656f
18
LTC2365/LTC2366
APPLICATIONS INFORMATION
LTC1566-1: Low Noise 2.3MHz Continuous Time LowPass Filter.
LT1630: Dual 30MHz Rail-to-Rail Voltage Feedback Amplifier. 2.7V to ±15V supplies. Very high AVOL, 500μV offset
and 520ns settling to 0.5LSB for a 4V swing. THD and noise
are –93dB to 40kHz and below 1LSB to 320kHz (AV = 1,
2VP-P into 1k, VS = 5V), making the part excellent for AC
applications (to 1/3 Nyquist) where rail-to-rail performance
is desired. Quad version is available as LT1631.
LT1632: Dual 45MHz Rail-to-Rail Voltage Feedback Amplifier. 2.7V to ±15V supplies. Very high AVOL, 1.5mV offset
and 400ns settling to 0.5LSB for a 4V swing. It is suitable
for applications with a single 5V supply. THD and noise
are –93dB to 40kHz and below 1LSB to 800kHz (AV = 1,
2VP-P into 1k, VS = 5V), making the part excellent for AC
applications where rail-to-rail performance is desired.
Quad version is available as LT1633.
LT1813: Dual 100MHz 750V/μs 3mA Voltage Feedback
Amplifier. 5V to ±5V supplies. Distortion is –86dB to
100kHz and –77dB to 1MHz with ±5V supplies (2VP-P
into 500). Excellent part for fast AC applications with ±5V
supplies.
LT1801: 180MHz GBWP, –75dBc at 500kHz, 2mA/Amplifier, 8.5nV/√Hz.
LT1806/LT1807: 325MHz GBWP, –80dBc Distortion at
5MHz, Unity-Gain Stable, R-R In and Out, 10mA/Amplifier, 3.5nV/√Hz.
LT1810: 180MHz GBWP, –90dBc Distortion at 5MHz,
Unity-Gain Stable, R-R In and Out, 15mA/Amplifier,
16nV/√Hz.
Input Filtering and Source Impedance
The noise and the distortion of the input amplifier and other
circuitry must be considered since they will add to the
LTC2365/LTC2366 noise and distortion. The small-signal
bandwidth of the sample-and-hold circuit is 50MHz. Any
noise or distortion products that are present at the analog
inputs will be summed over this entire bandwidth. Noisy
input circuitry should be filtered prior to the analog inputs
to minimize noise. A simple 1-pole RC filter is sufficient for
many applications. For example, Figure 18 shows a 47pF
capacitor from AIN to ground and a 51Ω source resistor to
limit the input bandwidth to 47MHz. The 47pF capacitor also
acts as a charge reservoir for the input sample-and-hold
and isolates the ADC input from sampling-glitch sensitive
circuitry. High quality capacitors and resistors should be
used since these components can add distortion. NPO
and silvermica type dielectric capacitors have excellent
linearity. Carbon surface mount resistors can generate
distortion from self heating and from damage that may
occur during soldering. Metal film surface mount resistors
are much less susceptible to both problems. When high
amplitude unwanted signals are close in frequency to the
desired signal frequency, a multiple pole filter is required.
High external source resistance, combined with the 20pF of
input capacitance, will reduce the rated 50MHz bandwidth
and increase acquisition time beyond 56ns.
LTC2366
1
10μF
47pF
CS
SD0
2
51Ω
LT1818/LT1819: 400MHz, 2500V/μs, 9mA, Single/Dual
Voltage Mode Operational Amplifier.
VDD
GND
SCK
6
5
4
3 A
IN
23656 F18
Figure 18. RC Input Filter
LT6200: 165MHz GBWP, –85dBc Distortion at 1MHz,
Unity-Gain Stable, R-R In and Out, 15mA/Amplifier,
0.95nV/√Hz.
LT6203: 100MHz GBWP, –80dBc Distortion at 1MHz,
Unity-Gain Stable, R-R In and Out, 3mA/Amplifier,
1.9nV√Hz.
LinearView is a trademark of Linear Technology Corpration
23656f
19
LTC2365/LTC2366
APPLICATIONS INFORMATION
Reference Input
On the TS8 package of the LTC2365/LTC2366, the voltage
on the VREF pin defines the full-scale range of the ADC. The
reference voltage can range from VDD down to 1.4V.
Input Range
The analog input of the LTC2365/LTC2366 is driven singleended with respect to GND from a single supply. The input
may swing up to VDD for the S6 package and to VREF for
the TS8 package. The 0V to 2.5V range is also ideally
suited for single-ended input use with VDD or VREF = 2.5V
for single supply applications. If the difference between
the AIN input and GND exceeds VDD for the S6 package or
VREF for the TS8 package, the output code will stay fixed
at all ones, and if this difference goes below 0V, the output
code will stay fixed at all zeros.
Figure 19 shows the ideal input/output characteristics for
the LTC2365/LTC2366. The code transitions occur midway between successive integer LSB values (i.e. 0.5LSB,
1.5LSB, 2.5LSB, …, FS –1.5LSB). The output code is
straight binary with 1LSB = VDD/4096 for the S6 package
and 1LSB = VREF /4096 for the TS8 package.
BOARD LAYOUT AND BYPASSING
Wire wrap boards are not recommended for high resolution and/or high speed A/D converters. To obtain the best
performance from the LTC2365/LTC2366, a printed circuit
board with ground plane is required. Layout for the printed
circuit board should ensure that digital and analog signal
lines are separated as much as possible. In particular, care
should be taken not to run any digital track alongside an
analog signal track or underneath the ADC. The analog
input should be screened by the ground plane.
111...111
UNIPOLAR OUTPUT CODE
111...110
000...001
000...000
0 1LSB
FS – 1LSB
INPUT VOLTAGE (V)
23656 F19
Figure 19. LTC2365/LTC2366 Transfer Characteristics
23656f
20
LTC2365/LTC2366
APPLICATIONS INFORMATION
High quality tantalum and ceramic bypass capacitors
should be used at the VDD and VREF pins as shown in the
Typical Application circuit on the first page of this data
sheet. For optimum performance, a 10μF surface mount
AVX capacitor with a 0.1μF ceramic is recommended for
the VDD pin and a 4.7μF surface mount AVX capacitor
with a 0.1μF ceramic is recommended for the VREF and
OVDD pins. Alternatively, 4.7μF and 10μF ceramic chip
capacitors such as Murata GRM235Y5V106Z016 may
be used. The capacitors must be located as close to the
pins as possible. The traces connecting the pins and the
bypass capacitors must be kept short and should be made
as wide as possible.
Figure 20 shows the recommended system ground connections. All analog circuitry grounds should be terminated
at the LTC2365/LTC2366. The ground return from the
LTC2365/LTC2366 to the power supply should be low
impedance for noise free operation. Digital circuitry grounds
must be connected to the digital supply common.
In applications where the ADC data outputs and control signals are connected to a continuously active microprocessor
bus, it is possible to get errors in the conversion results.
These errors are due to feedthrough from the microprocessor to the successive approximation comparator. The
problem can be eliminated by forcing the microprocessor
into a Wait state during conversion or by using three-state
buffers to isolate the ADC data bus.
CV DD
+
10μF
PIN 1
CAIN
VDD
CS
GND
SDO
AIN
SCK
VIAS TO GROUND PLANE
23656 F20
Figure 20. Power Supply Ground Practice
23656f
21
LTC2365/LTC2366
PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
1.4 MIN
3.85 MAX 2.62 REF
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
0.09 – 0.20
(NOTE 3)
1.90 BSC
S6 TSOT-23 0302 REV B
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
23656f
22
LTC2365/LTC2366
PACKAGE DESCRIPTION
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637)
0.52
MAX
2.90 BSC
(NOTE 4)
0.65
REF
1.22 REF
1.4 MIN
3.85 MAX 2.62 REF
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.22 – 0.36
8 PLCS (NOTE 3)
0.65 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
0.09 – 0.20
(NOTE 3)
1.95 BSC
TS8 TSOT-23 0802
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
23656f
23
LTC2365/LTC2366
TYPICAL APPLICATION
Low-Jitter Clock Timing with RF Sine Generator Using Clock
Squaring/Level Shifting Circuit and Re-Timing Flip-Flop
VCC
0.1μF
1k
NC7SVU04P5X
MASTER CLOCK
VCC
50Ω
1k
D
PRE
Q
Q
CONV
CLR
CONTROL
LOGIC
(FPGA, CPLD,
DSP, ETC.)
CONVERT ENABLE
NL17SZ74
CONV
LTC2366
SCK
NC7SVU04P5X
SDO
100Ω
2365/2366 TA02
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1402
12-Bit, 2.2Msps Serial ADC
5V or ±5V Supply, 4.096V or ±2.5V Span
LTC1403/LTC1403A
12-/14-Bit, 2.8Msps Serial Sampling ADC
3V, Differential Input, 12mW, MSOP Package
LTC1407/LTC1407A
12-/14-Bit, 3Msps Simultaneous Sampling ADC 3V, 2-Channel Differential, 14mW, MSOP Package
LTC1860
12-Bit, 250ksps Serial ADC
5V Supply, 1-Channel, 4.3mW, MSOP-8 Package
LTC1860L
12-Bit, 150ksps Serial ADC
3V Supply, 1-Channel, 1.3mW, MSOP-8 Package
LTC1861
12-Bit, 250ksps Serial ADC
5V Supply, 2-Channel, 4.3mW, MSOP-8 Package
LTC1861L
12-Bit, 150ksps Serial ADC
3V Supply, 2-Channel, 1.3mW, MSOP-8 Package
LTC1863
12-Bit, 200ksps Serial ADC 8-Channel ADC
5V Supply, 6.5mW, SSOP-16 Package, Pin Compatible to LTC1863L, LTC1867
LTC1863L
12-Bit, 250ksps Serial ADC 8-Channel ADC
5V Supply, 2.2mW, SSOP-16 Package, Pin Compatible to LTC1863, LTC1867L
LTC1864/LTC1865
16-Bit, 250ksps Serial ADC
5V Supply, 1 and 2 Channel, 4.3mW, MSOP Package
LTC1867
16-Bit, 200ksps Serial ADC 8-Channel ADC
5V Supply, 6.5mW, SSOP-16 Package, Pin Compatible to LTC1863, LTC1867L
LTC1867L
16-Bit, 175ksps Serial ADC 8-Channel ADC
3V Supply, 2.2mW, SSOP-16 Package, Pin Compatible to LTC1863L, LTC1867
LTC2355/LTC2356
12-/14-Bit, 3.5Msps Serial ADC
3.3V Supply, Differential Input, 18mW, MSOP Package
ADCs
LTC2360/LTC2361/LTC2362 12-Bit, 100/250/500ksps Serial ADC in TSOT
3V Supply, Pin- and Software-Compatible to LTC2365/LTC2366
DACs
LTC1592
16-Bit, Serial SoftSpan™ IOUT DAC
LTC1666/LTC1667/LTC1668 12-/14-/16-Bit, 50Msps DACs
±1LSB INL/DNL, Software Selectable Spans
87dB SFDR, 20ns Settling Time
12-/10-/8-Bit Single VOUT DACs
SC70 6-Pin Package, Internal Reference, ±1LSB INL (12 Bits)
LT1460-2.5
Micropower Series Voltage Reference
0.1% Initial Accuracy, 10ppm Drift
LT1461-2.5
Precision Voltage Reference
0.05% Initial Accuracy, 3ppm Drift
LT1790-2.5
Micropower Series Reference in SOT-23
0.05% Initial Accuracy, 10ppm Drift
LT6660
Ultra-Tiny Micropower Series Reference
2mm × 2mm DFN Package, 0.2% Initial Accuracy, 10ppm Drift
LTC2630
References
SoftSpan is a trademark of Linear Technology Corporation.
23656f
24 Linear Technology Corporation
LT 0408 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2008
Similar pages