LTC1864/LTC1865
µPower,
16-Bit, 250ksps
1- and 2-Channel ADCs in MSOP
FEATURES
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■
■
■
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DESCRIPTIO
16-Bit 250ksps ADCs in MSOP Package
Single 5V Supply
Low Supply Current: 850µA (Typ)
Auto Shutdown Reduces Supply Current
to 2µA at 1ksps
True Differential Inputs
1-Channel (LTC1864) or 2-Channel (LTC1865)
Versions
SPI/MICROWIRE
TM
Compatible Serial I/O
16-Bit Upgrade to 12-Bit LTC1286/LTC1298
Pin Compatible with 12-Bit LTC1860/LTC1861
The LTC
®
1864/LTC1865 are 16-bit A/D converters that are
offered in MSOP and SO-8 packages and operate on a
single 5V supply. At 250ksps, the supply current is only
850µA. The supply current drops at lower speeds because
the LTC1864/LTC1865 automatically power down
between conversions. These 16-bit switched capacitor
successive approximation ADCs include sample-and-holds.
The LTC1864 has a differential analog input with an
adjustable reference pin. The LTC1865 offers a software-
selectable 2-channel MUX and an adjustable reference pin
on the MSOP version.
The 3-wire, serial I/O, small MSOP or SO-8 package and
extremely high sample rate-to-power ratio make these
ADCs ideal choices for compact, low power, high speed
systems.
These ADCs can be used in ratiometric applications or
with external references. The high impedance analog
inputs and the ability to operate with reduced spans down
to 1V full scale, allow direct connection to signal sources
in many applications, eliminating the need for external
gain stages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
APPLICATIO S
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High Speed Data Acquisition
Portable or Compact Instrumentation
Low Power Battery-Operated Instrumentation
Isolated and/or Remote Data Acquisition
TYPICAL APPLICATIO
Supply Current vs Sampling Frequency
Single 5V Supply, 250ksps, 16-Bit Sampling ADC
SUPPLY CURRENT (µA)
1000
1µF
5V
100
10
LTC1864
1
2
ANALOG INPUT
0V TO 5V
3
4
V
REF
IN
+
IN
–
GND
V
CC
SCK
SDO
CONV
8
7
6
5
1864 TA01
1
SERIAL DATA LINK TO
ASIC, PLD, MPU, DSP
OR SHIFT REGISTERS
0.1
0.01
0.01
U
0.1
10
100
1
SAMPLING FREQUENCY (kHz)
1000
1864 TA02
U
U
sn18645 18645fs
1
LTC1864/LTC1865
ABSOLUTE
AXI U
RATI GS
Supply Voltage (V
CC
) ................................................. 7V
Ground Voltage Difference
AGND, DGND LTC1865 MSOP Package ...........
±0.3V
Analog Input ............... (GND – 0.3V) to (V
CC
+ 0.3V)
Digital Input ................................ (GND – 0.3V) to 7V
Digital Output .............. (GND – 0.3V) to (V
CC
+ 0.3V)
Power Dissipation .............................................. 400mW
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
REF
IN
+
IN¯
GND
1
2
3
4
8
7
6
5
V
CC
SCK
SDO
CONV
ORDER PART
NUMBER
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
LTC1864CMS8
LTC1864IMS8
LTC1864ACMS8
LTC1864AIMS8
MS8 PART MARKING
LTHQ
ORDER PART
NUMBER
T
JMAX
= 150°C,
θ
JA
= 210°C/W
TOP VIEW
V
REF
1
IN
+
2
IN
–
3
GND 4
8 V
CC
7 SCK
6 SDO
5 CONV
LTC1864CS8
LTC1864IS8
LTC1864ACS8
LTC1864AIS8
S8 PART MARKING
1864
1864I
1864A
1864AI
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 175°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
CO VERTER A D
PARAMETER
Resolution
No Missing Codes Resolution
INL
Transition Noise
Gain Error
ULTIPLEXER CHARACTERISTICS
LTC1864/LTC1865
MIN
TYP
MAX
●
●
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
CC
= 5V, V
REF
= 5V, f
SCK
= f
SCK(MAX)
as defined in Recommended Operating Conditions, unless otherwise noted.
CONDITIONS
LTC1864A/LTC1865A
MIN
TYP
MAX
16
15
±8
1.1
●
(Note 3)
2
U
U
W
W W
U
W U
W
(Notes 1, 2)
Operating Temperature Range
LTC1864C/LTC1865C/
LTC1864AC/LTC1865AC ........................ 0°C to 70°C
LTC1864I/LTC1865I/
LTC1864AI/LTC1865AI ..................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
CONV
CH0
CH1
AGND
DGND
1
2
3
4
5
10
9
8
7
6
V
REF
V
CC
SCK
SDO
SDI
MS PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 150°C,
θ
JA
= 210°C/W
LTC1865CMS
LTC1865IMS
LTC1865ACMS
LTC1865AIMS
MS PART MARKING
LTHS
ORDER PART
NUMBER
TOP VIEW
CONV 1
CH0 2
CH1 3
GND 4
8 V
CC
7 SCK
6 SDO
5 SDI
LTC1865CS8
LTC1865IS8
LTC1865ACS8
LTC1865AIS8
S8 PART MARKING
1865
1865I
1865A
1865AI
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 175°C/W
U
UNITS
Bits
Bits
16
14
●
±6
1.1
±20
LSB
LSB
RMS
mV
±20
sn18645 18645fs
LTC1864/LTC1865
CO VERTER A D
PARAMETER
Offset Error
Input Differential Voltage Range
Absolute Input Range
V
REF
Input Range
Analog Input Leakage Current
C
IN
Input Capacitance
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
CC
= 5V, V
REF
= 5V, f
SCK
= f
SCK(MAX)
as defined in Recommended Operating Conditions, unless otherwise noted.
CONDITIONS
LTC1864 SO-8 and MSOP, LTC1865 MSOP
●
LTC1865 SO-8
●
V
IN
= IN
+
– IN
–
IN
+
Input
IN
–
Input
LTC1864 SO-8 and MSOP,
LTC1865 MSOP
(Note 4)
In Sample Mode
During Conversion
●
●
DY A IC ACCURACY
T
A
= 25°C. V
CC
= 5V, V
REF
= 5V, f
SAMPLE
= 250kHz, unless otherwise noted.
SYMBOL PARAMETER
SNR
Signal-to-Noise Ratio
10kHz Input Signal
100kHz Input Signal
S/(N + D) Signal-to-Noise Plus Distortion Ratio
THD
CONDITIONS
LTC1864/LTC1865
MIN
TYP
MAX
87
83
76
88
77
20
S/(N + D)
≥
75dB
125
UNITS
dB
dB
dB
dB
dB
MHz
kHz
Total Hamonic Distortion Up to 5th Harmonic 10kHz Input Signal
100kHz Input Signal
Full Power Bandwidth
Full Linear Bandwidth
DIGITAL A D DC ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
IH
V
IL
I
IH
I
IL
V
OH
V
OL
I
OZ
I
SOURCE
I
SINK
I
REF
I
CC
P
D
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
High Level Output Voltage
Low Level Output Voltage
Hi-Z Output Leakage
Output Source Current
Output Sink Current
Reference Current (LTC1864 SO-8 and
MSOP, LTC1865 MSOP)
Supply Current
Power Dissipation
CONDITION
V
CC
= 5.25V
V
CC
= 4.75V
V
IN
= V
CC
V
IN
= 0V
V
CC
= 4.75V, I
O
= 10µA
V
CC
= 4.75V, I
O
= 360µA
V
CC
= 4.75V, I
O
= 1.6mA
CONV = V
CC
V
OUT
= 0V
V
OUT
= V
CC
CONV = V
CC
f
SMPL
= f
SMPL(MAX)
CONV = V
CC
After Conversion
f
SMPL
= f
SMPL(MAX)
f
SMPL
= f
SMPL(MAX)
The
●
denotes specifications which apply
over the full operating temperature range, otherwise specifications are T
A
= 25°C. V
CC
= 5V, V
REF
= 5V, unless otherwise noted.
LTC1864/LTC1865
MIN
TYP
MAX
●
●
●
●
●
●
●
●
W U
U
W U
U
ULTIPLEXER CHARACTERISTICS
LTC1864/LTC1865
MIN
TYP
MAX
±2
±3
0
– 0.05
– 0.05
1
±5
±7
V
REF
V
CC
+ 0.05
V
CC
/2
V
CC
±1
12
5
12
5
0
– 0.05
– 0.05
1
LTC1864A/LTC1865A
MIN
TYP
MAX
±2
±3
±5
±7
V
REF
V
CC
+ 0.05
V
CC
/2
V
CC
±1
UNITS
mV
mV
V
V
V
V
µA
pF
pF
UNITS
V
V
µA
µA
V
V
2.4
0.8
2.5
– 2.5
4.5
2.4
4.74
4.72
0.4
±3
– 25
20
V
µA
mA
mA
●
●
●
●
0.001
0.05
0.001
0.85
4.25
3
0.1
3
1.3
µA
mA
µA
mA
mW
sn18645 18645fs
3
LTC1864/LTC1865
RECO
V
CC
f
SCK
t
CYC
t
SMPL
t
suCONV
t
hDI
t
suDI
t
WHCLK
t
WLCLK
t
WHCONV
t
WLCONV
t
hCONV
full operating temperature range, otherwise specifications are T
A
= 25°C.
CONDITIONS
E DED OPERATI G CO DITIO S
SYMBOL PARAMETER
Supply Voltage
Clock Frequency
Total Cycle Time
Analog Input Sampling Time
Setup Time CONV↓ Before First SCK↑
(See Figure 1)
Hold Time SDI After SCK↑
Setup Time SDI Stable Before SCK↑
SCK High Time
SCK Low Time
CONV High Time Between Data
Transfer Cycles
CONV Low Time During Data Transfer
Hold Time CONV Low After Last SCK↑
LTC1864
LTC1865
LTC1865
LTC1865
f
SCK
= f
SCK(MAX)
f
SCK
= f
SCK(MAX)
The
●
denotes specifications which apply over the full operating temperature
range, otherwise specifications are T
A
= 25°C. V
CC
= 5V, V
REF
= 5V, f
SCK
= f
SCK(MAX)
as defined in Recommended Operating
Conditions, unless otherwise noted.
SYMBOL
t
CONV
t
dDO
t
dis
t
en
t
hDO
t
r
t
f
PARAMETER
Conversion Time (See Figure 1)
Delay Time, SCK↓ to SDO Data Valid
Delay Time, CONV↑ to SDO Hi-Z
Delay Time, CONV↓ to SDO Enabled
Time Output Data Remains
Valid After SCK↓
SDO Rise Time
SDO Fall Time
C
LOAD
= 20pF
C
LOAD
= 20pF
C
LOAD
= 20pF
C
LOAD
= 20pF
C
LOAD
= 20pF
CONDITIONS
●
●
●
●
●
●
TI I G CHARACTERISTICS
f
SMPL(MAX)
Maximum Sampling Frequency
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 GND.
Note 3:
Integral nonlinearity is defined as 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 4:
Channel leakage current is measured while the part is in sample
mode.
4
U
U
U
U WW
The
●
denotes specifications which apply over the
LTC1864/LTC1865
MIN
TYP
MAX
4.75
●
UNITS
V
MHz
µs
SCK
SCK
ns
ns
ns
1/f
SCK
1/f
SCK
µs
SCK
ns
5.25
20
DC
16 • SCK + t
CONV
16
14
30
15
15
40%
40%
t
CONV
16
13
UW
LTC1864/LTC1865
MIN
TYP
MAX
2.75
250
15
30
30
5
10
8
4
20
25
60
60
3.2
UNITS
µs
kHz
ns
ns
ns
ns
ns
ns
ns
sn18645 18645fs
LTC1864/LTC1865
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Sampling
Frequency
1000
V
CC
= 5V
T
A
= 25°C
CONV LOW = 800ns
1000
100
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
SLEEP CURRENT (nA)
10
1
0.1
0.01
0.01
0.1
10
100
1.0
SAMPLING FREQUENCY (kHz)
Reference Current vs
Sampling Rate
60
50
V
CC
= 5V
T
A
= 25°C
V
REF
= 5V
CONV LOW = 800ns
REFERENCE CURRENT (µA)
REFERENCE CURRENT (µA)
40
30
20
10
0
52
51
50
49
48
47
46
REFERENCE CURRENT (µA)
0
50
100
150
200
SAMPLE RATE (kHz)
Typical INL Curve
4
V
CC
= 5V
T
A
= 25°C
V
REF
= 5V
2
DNL ERROR (LSBs)
INL ERROR (LSBs)
ANALOG INPUT LEAKAGE (nA)
0
–2
–4
0
16384
32768
CODE
49152
U W
1864/65 G01
1864/65 G04
Supply Current vs Temperature
1000
900
800
Sleep Current vs Temperature
CONV = V
CC
= 5V
800
700
600
500
400
300
200
100
0
–50
–25
50
25
75
0
TEMPERATURE (°C)
100
125
600
400
V
CC
= 5V
V
REF
= 5V
f
SAMPLE
= 250kHz
CONV HIGH = 3.2µS
–25
50
25
75
0
TEMPERATURE (°C)
100
125
200
1000
0
–50
1864/65 G02
1864/65 G03
Reference Current vs
Temperature
55
V
CC
= 5V
54 V
REF
= 5V
f = 250kHz
53
S
60
50
40
30
20
10
0
Reference Current vs
Reference Voltage
V
CC
= 5V
T
A
= 25°C
f
S
= 250kHz
250
45
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
0
1
2
3
V
REF
(V)
4
5
1864/65 G06
1864/65 G05
Typical DNL Curve
2
100
Analog Input Leakage Current vs
Temperature
V
CC
= 5V
V
REF
= 5V
CONV = 0V
V
CC
= 5V
T
A
= 25°C
V
REF
= 5V
1
75
0
50
–1
25
65536
1864/65 G07
–2
0
16384
32768
CODE
49152
65536
1864/65 G08
0
–50 –25
0
25
50
75
100
125
TEMPERATURE (°C)
1864/65 G09
sn18645 18645fs
5
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