1
LTC1864/LTC1865
18645f
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATIO
U
Power, 16-Bit, 250ksps
1- and 2-Channel ADCs in MSOP
Single 5V Supply, 250ksps, 16-Bit Sampling ADC
Supply Current vs Sampling Frequency
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
850
A. 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.
s
16-Bit 250ksps ADCs in MSOP Package
s
Single 5V Supply
s
Low Supply Current: 850
A (Typ)
s
Auto Shutdown Reduces Supply Current
to 2
A at 1ksps
s
True Differential Inputs
s
1-Channel (LTC1864) or 2-Channel (LTC1865)
Versions
s
SPI/MICROWIRE
TM
Compatible Serial I/O
s
16-Bit Upgrade to 12-Bit LTC1286/LTC1298
s
Pin Compatible with 12-Bit LTC1860/LTC1861
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
High Speed Data Acquisition
s
Portable or Compact Instrumentation
s
Low Power Battery-Operated Instrumentation
s
Isolated and/or Remote Data Acquisition
1
2
3
4
8
7
6
5
V
REF
IN
+
IN
GND
V
CC
SCK
SDO
CONV
LTC1864
1864 TA01
ANALOG INPUT
0V TO 5V
5V
1
F
SERIAL DATA LINK TO
ASIC, PLD, MPU, DSP
OR SHIFT REGISTERS
SAMPLING FREQUENCY (kHz)
0.01
SUPPLY CURRENT (
A)
1000
100
10
1
0.1
0.01
100
1864 TA02
0.1
1
10
1000
MICROWIRE is a trademark of National Semiconductor Corporation.
2
LTC1864/LTC1865
18645f
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
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
(Notes 1, 2)
ORDER PART
NUMBER
MS8 PART MARKING
MS PART MARKING
LTHS
LTHT
LTC1865CMS
LTC1865IMS
LTC1865ACMS
LTC1865AIMS
ORDER PART
NUMBER
LTC1864CMS8
LTC1864IMS8
LTC1864ACMS8
LTC1864AIMS8
LTHQ
LTHR
T
JMAX
= 150
C,
JA
= 210
C/W
T
JMAX
= 150
C,
JA
= 210
C/W
1
2
3
4
V
REF
IN
+
IN
GND
8
7
6
5
V
CC
SCK
SDO
CONV
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
ABSOLUTE AXI U RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
LTVL
LTVM
ORDER PART
NUMBER
S8 PART MARKING
S8 PART MARKING
1864
1864I
LTC1864CS8
LTC1864IS8
LTC1864ACS8
LTC1864AIS8
ORDER PART
NUMBER
T
JMAX
= 150
C,
JA
= 175
C/W
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
V
REF
IN
+
IN
GND
V
CC
SCK
SDO
CONV
1864A
1864AI
LTVN
LTVP
1865
1865I
LTC1865CS8
LTC1865IS8
LTC1865ACS8
LTC1865AIS8
1865A
1865AI
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
CONV
CH0
CH1
GND
V
CC
SCK
SDO
SDI
T
JMAX
= 150
C,
JA
= 175
C/W
1
2
3
4
5
CONV
CH0
CH1
AGND
DGND
10
9
8
7
6
V
REF
V
CC
SCK
SDO
SDI
TOP VIEW
MS PACKAGE
10-LEAD PLASTIC MSOP
LTC1864/LTC1865
LTC1864A/LTC1865A
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Resolution
q
16
16
Bits
No Missing Codes Resolution
q
14
15
Bits
INL
(Note 3)
q
8
6
LSB
Transition Noise
1.1
1.1
LSB
RMS
Gain Error
q
20
20
mV
The
q
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.
CO VERTER A D ULTIPLEXER CHARACTERISTICS
U
W
U
Consult LTC Marketing for parts specified with wider operating temperature ranges.
3
LTC1864/LTC1865
18645f
LTC1864/LTC1865
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
SNR
Signal-to-Noise Ratio
87
dB
S/(N + D) Signal-to-Noise Plus Distortion Ratio
10kHz Input Signal
83
dB
100kHz Input Signal
76
dB
THD
Total Hamonic Distortion Up to 5th Harmonic 10kHz Input Signal
88
dB
100kHz Input Signal
77
dB
Full Power Bandwidth
20
MHz
Full Linear Bandwidth
S/(N + D)
75dB
125
kHz
LTC1864/LTC1865
LTC1864A/LTC1865A
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Offset Error
LTC1864 SO-8 and MSOP, LTC1865 MSOP
q
2
5
2
5
mV
LTC1865 SO-8
q
3
7
3
7
mV
Input Differential Voltage Range
V
IN
= IN
+
IN
q
0
V
REF
0
V
REF
V
Absolute Input Range
IN
+
Input
0.05
V
CC
+ 0.05
0.05
V
CC
+ 0.05
V
IN
Input
0.05
V
CC
/2
0.05
V
CC
/2
V
V
REF
Input Range
LTC1864 SO-8 and MSOP,
1
V
CC
1
V
CC
V
LTC1865 MSOP
Analog Input Leakage Current
(Note 4)
q
1
1
A
C
IN
Input Capacitance
In Sample Mode
12
12
pF
During Conversion
5
5
pF
The
q
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.
DY
A
IC ACCURACY
U
W
DIGITAL A D DC ELECTRICAL CHARACTERISTICS
U
The
q
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.
CO VERTER A D ULTIPLEXER CHARACTERISTICS
U
W
U
T
A
= 25
C. V
CC
= 5V, V
REF
= 5V, f
SAMPLE
= 250kHz, unless otherwise noted.
LTC1864/LTC1865
SYMBOL
PARAMETER
CONDITION
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
V
CC
= 5.25V
q
2.4
V
V
IL
Low Level Input Voltage
V
CC
= 4.75V
q
0.8
V
I
IH
High Level Input Current
V
IN
= V
CC
q
2.5
A
I
IL
Low Level Input Current
V
IN
= 0V
q
2.5
A
V
OH
High Level Output Voltage
V
CC
= 4.75V, I
O
= 10
A
q
4.5
4.74
V
V
CC
= 4.75V, I
O
= 360
A
q
2.4
4.72
V
V
OL
Low Level Output Voltage
V
CC
= 4.75V, I
O
= 1.6mA
q
0.4
V
I
OZ
Hi-Z Output Leakage
CONV = V
CC
q
3
A
I
SOURCE
Output Source Current
V
OUT
= 0V
25
mA
I
SINK
Output Sink Current
V
OUT
= V
CC
20
mA
I
REF
Reference Current (LTC1864 SO-8 and
CONV = V
CC
q
0.001
3
A
MSOP, LTC1865 MSOP)
f
SMPL
= f
SMPL(MAX)
q
0.05
0.1
mA
I
CC
Supply Current
CONV = V
CC
After Conversion
q
0.001
3
A
f
SMPL
= f
SMPL(MAX)
q
0.85
1.3
mA
P
D
Power Dissipation
f
SMPL
= f
SMPL(MAX)
4.25
mW
4
LTC1864/LTC1865
18645f
LTC1864/LTC1865
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC
Supply Voltage
4.75
5.25
V
f
SCK
Clock Frequency
q
DC
20
MHz
t
CYC
Total Cycle Time
16 SCK + t
CONV
s
t
SMPL
Analog Input Sampling Time
LTC1864
16
SCK
LTC1865
14
SCK
t
suCONV
Setup Time CONV
Before First SCK
30
ns
(See Figure 1)
t
hDI
Hold Time SDI After SCK
LTC1865
15
ns
t
suDI
Setup Time SDI Stable Before SCK
LTC1865
15
ns
t
WHCLK
SCK High Time
f
SCK
= f
SCK(MAX)
40%
1/f
SCK
t
WLCLK
SCK Low Time
f
SCK
= f
SCK(MAX)
40%
1/f
SCK
t
WHCONV
CONV High Time Between Data
t
CONV
s
Transfer Cycles
t
WLCONV
CONV Low Time During Data Transfer
16
SCK
t
hCONV
Hold Time CONV Low After Last SCK
13
ns
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.
The
q
denotes specifications which apply over the
full operating temperature range, otherwise specifications are T
A
= 25
C.
LTC1864/LTC1865
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
CONV
Conversion Time (See Figure 1)
q
2.75
3.2
s
f
SMPL(MAX)
Maximum Sampling Frequency
q
250
kHz
t
dDO
Delay Time, SCK
to SDO Data Valid
C
LOAD
= 20pF
15
20
ns
q
25
ns
t
dis
Delay Time, CONV
to SDO Hi-Z
q
30
60
ns
t
en
Delay Time, CONV
to SDO Enabled
C
LOAD
= 20pF
q
30
60
ns
t
hDO
Time Output Data Remains
C
LOAD
= 20pF
q
5
10
ns
Valid After SCK
t
r
SDO Rise Time
C
LOAD
= 20pF
8
ns
t
f
SDO Fall Time
C
LOAD
= 20pF
4
ns
The
q
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.
RECO
E
DED OPERATI
G CO DITIO
S
U
U
U
U
W
W
TI I G CHARACTERISTICS
U
W
5
LTC1864/LTC1865
18645f
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
SAMPLING FREQUENCY (kHz)
0.01
SUPPLY CURRENT (
A)
1000
100
10
1
0.1
0.01
100
1864/65 G01
0.1
1.0
10
1000
V
CC
= 5V
T
A
= 25
C
CONV LOW = 800ns
TEMPERATURE (
C)
50
SUPPLY CURRENT (
A)
1000
800
600
400
200
0
0
50
75
1864/65 G02
25
25
100
125
V
CC
= 5V
V
REF
= 5V
f
SAMPLE
= 250kHz
CONV HIGH = 3.2
S
TEMPERATURE (
C)
50
SLEEP CURRENT (nA)
1000
900
800
700
600
500
400
300
200
100
0
0
50
75
1864/65 G03
25
25
100
125
CONV = V
CC
= 5V
SAMPLE RATE (kHz)
0
REFERENCE CURRENT (
A)
60
50
40
30
20
10
0
50
100
150
200
1864/65 G04
250
V
CC
= 5V
T
A
= 25
C
V
REF
= 5V
CONV LOW = 800ns
TEMPERATURE (
C)
50
REFERENCE CURRENT (
A)
55
54
53
52
51
50
49
48
47
46
45
0
50
75
1864/65 G05
25
25
100
125
V
CC
= 5V
V
REF
= 5V
f
S
= 250kHz
V
REF
(V)
0
REFERENCE CURRENT (
A)
60
50
40
30
20
10
0
1
2
3
4
1864/65 G06
5
V
CC
= 5V
T
A
= 25
C
f
S
= 250kHz
TEMPERATURE (
C)
50
ANALOG INPUT LEAKAGE (nA)
100
1864/65 G09
0
50
100
75
50
25
0
25
25
75
125
V
CC
= 5V
V
REF
= 5V
CONV = 0V
CODE
0
INL ERROR (LSBs)
65536
1864/65 G07
32768
4
2
0
2
4
16384
49152
V
CC
= 5V
T
A
= 25
C
V
REF
= 5V
CODE
0
65536
1864/65 G08
32768
16384
49152
DNL ERROR (LSBs)
2
1
0
1
2
V
CC
= 5V
T
A
= 25
C
V
REF
= 5V
Supply Current vs Sampling
Frequency
Supply Current vs Temperature
Sleep Current vs Temperature
Reference Current vs
Sampling Rate
Reference Current vs
Temperature
Reference Current vs
Reference Voltage
Typical INL Curve
Typical DNL Curve
Analog Input Leakage Current vs
Temperature
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