1865L Layout
1
LTC1865L
1865li
Power, 3V, 16-Bit, 150ksps
2-Channel ADC in MSOP
November 2002
Single 3V Supply, 150ksps, 16-Bit Sampling ADC
Supply Current vs Sampling Frequency
The LTC
1865L is a 16-bit A/D converter that is offered in
MSOP and SO-8 packages and operates on a single 3V
supply. At 150ksps, the supply current is only 450
A. The
supply current drops at lower speeds because the
LTC1865L automatically powers down to a typical supply
current of 1nA between conversions. This 16-bit switched
capacitor successive approximation ADC includes a
sample-and-hold. The LTC1865L offers a software-select-
able 2-channel MUX. An adjustable reference pin is pro-
vided on the MSOP version.
The 4-wire, serial I/O, MSOP or SO-8 package and
extremely high sample rate-to-power ratio make this ADC
an ideal choice for compact, low power, high speed
systems.
This ADC 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 150ksps ADC in MSOP Package
s
Single 3V Supply
s
Low Supply Current: 450
A (Typ)
s
Auto Shutdown Reduces Supply Current
to 10
A at 1ksps
s
SPI/MICROWIRE
TM
Compatible Serial I/O
s
16-Bit Upgrade to 12-Bit LTC1288
s
Pin Compatible with 12-Bit LTC1861L
, 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
1865L TA01
ANALOG
INPUTS
0V TO 3V
3V
1
F
SERIAL DATA LINK TO
ASIC, PLD, MPU, DSP
OR SHIFT REGISTERS
CONV
SCK
SDO
SDI
V
REF
V
CC
AGND
DGND
LTC1865L
CH0
CH1
MICROWIRE is a trademark of National Semiconductor Corporation.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
Final Electrical Specifications
TYPICAL APPLICATIO
U
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SAMPLING FREQUENCY (kHz)
0.01
SUPPLY CURRENT (
A)
1000
100
10
1
0.1
100
1865 TA02
0.1
1
10
1000
V
CC
= 2.7V
T
A
= 25
C
CONV LOW = 2
s
2
LTC1865L
1865li
Power Dissipation .............................................. 400mW
Operating Temperature Range
LTC1865LC ............................................ 0
C to 70
C
LTC1865LI ........................................ 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 (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)
(Notes 1, 2)
MS PART MARKING
LTJ4
LTJ5
LTC1865LCMS
LTC1865LIMS
LTC1865LACMS
LTC1865LAIMS
ORDER PART
NUMBER
T
JMAX
= 150
C,
JA
= 210
C/W
ABSOLUTE AXI U RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
S8 PART MARKING
ORDER PART
NUMBER
LTJ6
LTJ7
1865L
1865LI
LTC1865LCS8
LTC1865LIS8
LTC1865LACS8
LTC1865LAIS8
1865LA
865LAI
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
LTC1865L
LTC1865LA
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
2
2
LSB
RMS
Gain Error
q
20
20
mV
Offset Error
q
2
5
2
5
mV
Analog Input Range
+CH GND or (CH)
q
0
V
REF
0
V
REF
V
Absolute Input Range
+CH Input
0.05
V
CC
+ 0.05
0.05
V
CC
+ 0.05
V
CH Input
0.05
V
CC
/2
0.05
V
CC
/2
V
V
REF
Input Range
MSOP
1
V
CC
1
V
CC
V
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
= 2.7V, V
REF
= 2.5V (MSOP) or V
REF
= V
CC
(SO), 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
LTC1865L
1865li
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
SNR
Signal-to-Noise Ratio
82
dB
S/(N + D) Signal-to-Noise Plus Distortion Ratio
1kHz Input Signal
82
dB
THD
Total Hamonic Distortion Up to 5th Harmonic 1kHz Input Signal
92
dB
Full Power Bandwidth
10
MHz
Full Linear Bandwidth
S/(N + D)
75dB
20
kHz
The
q
denotes specifications which apply
over the full operating temperature range, otherwise specifications are T
A
= 25
C. V
CC
= 2.7V, V
REF
= 2.5V (MSOP) or V
REF
= V
CC
(SO),
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
= 3V, V
REF
= 3V, f
SAMPLE
= 150kHz, unless otherwise noted.
SYMBOL
PARAMETER
CONDITION
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
V
CC
= 3.3V
q
1.9
V
V
IL
Low Level Input Voltage
V
CC
= 2.7V
q
0.45
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
= 2.7V, I
O
= 10
A
q
2.3
2.60
V
V
CC
= 2.7V, I
O
= 360
A
q
2.1
2.45
V
V
OL
Low Level Output Voltage
V
CC
= 2.7V, I
O
= 400
A
q
0.3
V
I
OZ
Hi-Z Output Leakage
CONV = V
CC
q
3
A
I
SOURCE
Output Source Current
V
OUT
= 0V
6.5
mA
I
SINK
Output Sink Current
V
OUT
= V
CC
6.5
mA
I
REF
Reference Current (MSOP)
CONV = V
CC
q
0.001
3
A
f
SMPL
= f
SMPL(MAX)
q
0.01
0.1
mA
I
CC
Supply Current
CONV = V
CC
After Conversion
q
0.5
10
A
f
SMPL
= f
SMPL(MAX)
q
0.45
1
mA
P
D
Power Dissipation
f
SMPL
= f
SMPL(MAX)
1.22
mW
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC
Supply Voltage
2.7
3.6
V
f
SCK
Clock Frequency
q
DC
8
MHz
t
CYC
Total Cycle Time
16 SCK + t
CONV
s
t
SMPL
Analog Input Sampling Time
14
SCK
t
suCONV
Setup Time CONV
Before First SCK
60
ns
(See Figure 1)
t
hDI
Hold Time SDI After SCK
30
ns
t
suDI
Setup Time SDI Stable Before SCK
30
ns
t
WHCLK
SCK High Time
f
SCK
= f
SCK(MAX)
45%
1/f
SCK
t
WLCLK
SCK Low Time
f
SCK
= f
SCK(MAX)
45%
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
26
ns
The
q
denotes specifications which apply over the
full operating temperature range, otherwise specifications are T
A
= 25
C.
RECO
E
DED OPERATI
G CO DITIO
S
U
U
U
U
W
W
4
LTC1865L
1865li
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.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
CONV
Conversion Time (See Figure 1)
q
3.7
4.66
s
f
SMPL(MAX)
Maximum Sampling Frequency
q
150
kHz
t
dDO
Delay Time, SCK
to SDO Data Valid
C
LOAD
= 20pF
45
55
ns
q
60
ns
t
dis
Delay Time, CONV
to SDO Hi-Z
q
55
120
ns
t
en
Delay Time, CONV
to SDO Enabled
C
LOAD
= 20pF
q
35
120
ns
t
hDO
Time Output Data Remains
C
LOAD
= 20pF
q
5
15
ns
Valid After SCK
t
r
SDO Rise Time
C
LOAD
= 20pF
25
ns
t
f
SDO Fall Time
C
LOAD
= 20pF
12
ns
The
q
denotes specifications which apply over the full operating temperature
range, otherwise specifications are T
A
= 25
C. V
CC
= 2.7V, V
REF
= 2.5V (MSOP) or V
REF
= V
CC
(SO), f
SCK
= f
SCK(MAX)
as defined in
Recommended Operating Conditions, unless otherwise noted.
TI I G CHARACTERISTICS
U
W
5
LTC1865L
1865li
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Supply Current vs Sampling
Frequency
Typical INL Curve
Typical DNL Curve
4096 Point FFT Nonaveraged
SINAD vs Input Frequency
SNR vs Input Frequency
THD vs Input Frequency
SFDR vs Input Frequency
CODE
0
INL ERROR (LSBs)
0
2
65536
1865 G02
2
4
16384
32768
49152
4
V
CC
= 2.7V
V
REF
= 2.5V
CODE
0
DNL ERROR (LSBs)
0
1
65536
1865 G03
1
2
16384
32768
49152
2
V
CC
= 2.7V
V
REF
= 2.5V
INPUT FREQUENCY (kHz)
0
AMPLITUDE (dB)
60
1865 G04
5 10 15 20 25
35 40
50 55
65
30
45
0
10
20
30
40
50
60
70
80
90
100
110
120
130
V
CC
= 3V
V
REF
= 3V
f
S
= 125kHz
f
IN
= 1kHz
f
IN
(kHz)
1
SINAD (dB)
1865 G05
100
90
80
70
60
50
40
30
20
10
0
100
10
V
CC
= 3V
V
REF
3V
f
S
= 125kHz
f
IN
(kHz)
1
SNR (dB)
1865 G06
100
90
80
70
60
50
40
30
20
10
0
100
10
V
CC
= 3V
V
REF
3V
f
S
= 125kHz
f
IN
(kHz)
1
THD (dB)
1865 G07
0
10
20
30
40
50
60
70
80
90
100
100
10
V
CC
= 3V
V
REF
3V
f
S
= 125kHz
f
IN
(kHz)
1
SFDR (dB)
1865 G08
100
90
80
70
60
50
40
30
20
10
0
100
10
V
CC
= 3V
V
REF
3V
f
S
= 125kHz
SAMPLING FREQUENCY (kHz)
0.01
SUPPLY CURRENT (
A)
1000
100
10
1
0.1
100
1865 TA02
0.1
1
10
1000
V
CC
= 2.7V
T
A
= 25
C
CONV LOW = 2
s
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