LTC1091/LTC1092
LTC1093/LTC1094
1-, 2-, 6- and 8-Channel, 10-Bit
Serial I/O Data Acquisition Systems
FEATURES
s
s
s
s
s
s
s
s
s
Programmable Features
– Unipolar/Bipolar Conversions
– Differential/Single-Ended Multiplexer
Configurations
Sample-and-Holds
Single Supply 5V, 10V or
±5V
Operation
Direct 3- or 4-Wire Interface to Most MPU Serial
Ports and All MPU Parallel I/O Ports
Analog Inputs Common Mode to Supply Rails
Resolution: 10 Bits
Total Unadjusted Error (A Grade):
±1LSB
Over Temp
Fast Conversion Time: 20µs
Low Supply Current
LTC1091: 3.5mA Max, 1.5mA Typ
LTC1092/LTC1093/LTC1094: 2.5mA Max, 1mA Typ
and-holds. On-chip serial ports allow efficient data trans-
fer to a wide range of microprocessors and microcontrol-
lers. These circuits can provide a complete data acquisi-
tion system in ratiometric applications or can be used with
an external reference in others.
The high impedance analog inputs and the ability to
operate with reduced spans (below 1V full scale) allow
direct connection to sensors and transducers in many
applications, eliminating the need for gain stages.
An efficient serial port communicates without external
hardware to most MPU serial ports and all MPU parallel
I/O ports allowing eight channels of data to be transmitted
over as few as three wires. This, coupled with low power
consumption, makes remote location possible and facili-
tates transmitting data through isolation barriers.
Temperature drift of offset, linearity and full-scale error
are all extremely low (1ppm/°C typically) allowing all
grades to be specified with offset and linearity errors of
±0.5LSB
maximum over temperature. In addition, the A
grade devices are specified with full-scale error and total
unadjusted error (including the effects of offset, linearity
and full-scale errors) of
±1LSB
maximum over tempera-
ture. The lower grade has a full-scale specification of
±2LSB
for applications where full scale is adjustable or
less critical.
, LTC and LT are registered trademarks of Linear Technology Corporation.
DESCRIPTIO
The LTC
®
1091/LTC1092/LTC1093/LTC1094 10-bit data
acquisition systems are designed to provide complete
function, excellent accuracy and ease of use when digitiz-
ing analog data from a wide variety of signal sources and
transducers. Built around a 10-bit, switched capacitor,
successive approximation A/D core, these devices include
software configurable analog multiplexers and bipolar and
unipolar conversion modes as well as on-chip sample-
TYPICAL APPLICATION
1.25
LINEARITY ERROR (LSB = 1 • V
REF
)
1024
5V
ANALOG INPUT #1
0V TO 5V RANGE
ANALOG INPUT #2
0V TO 5V RANGE
V
CC
8
(V
REF
)
7
2
CLK
CH0
LTC1091
6
3
D
OUT
CH1
5
4
D
IN
GND
1
CS
U
U
4.7µF
P1.4
P1.3
P1.2
SERIAL DATA LINK
V
CC
= 5V
1.00
MPU
(e.g., 8051)
0.75
0.50
0.25
1091 TA01
FOR 8051 CODE SEE
APPLICATIONS INFORMATION
SECTION
0
0
1
3
4
2
REFERENCE VOLTAGE (V)
5
1091 TA02
1
LTC1091/LTC1092
LTC1093/LTC1094
ABSOLUTE
AXI U
RATI GS
Supply Voltage (V
CC
) to GND or V
–
........................ 12V
Negative Supply Voltage (V
–
) .................... – 6V to GND
Voltage
Analog Reference and LTC1091/2 CS
Inputs ................................. (V
–
) – 0.3V to (V
CC
+ 0.3V)
Digital Inputs (except LTC1091/2 CS) .. – 0.3V to 12V
Digital Outputs ........................ – 0.3V to (V
CC
+ 0.3V)
PACKAGE/ORDER I FOR ATIO
TOP VIEW
CS 1
CH0 2
CH1 3
GND 4
N8 PACKAGE
8-LEAD PDIP
T
JMAX
= 110°C,
θ
JA
= 150°C/W (N)
8
7
6
5
V
CC
(V
REF
)
CLK
D
OUT
D
IN
ORDER PART
NUMBER
LTC1091ACN8
LTC1091CN8
TOP VIEW
CH0
CH1
CH2
CH3
CH4
CH5
COM
DGND
1
2
3
4
5
6
7
8
16 V
CC
15 CLK
14 CS
13 D
OUT
12 D
IN
11 V
REF
10 AGND
9
V
–
LTC1093ACN
LTC1093CN
LTC1093CSW
N PACKAGE
SW PACKAGE
16-LEAD PDIP 16-LEAD PLASTIC SO WIDE
T
JMAX
= 110°C,
θ
JA
= 150°C/W (N)
T
JMAX
= 110°C,
θ
JA
= 130°C/W (SW)
Consult factory for Industrial and Military grade parts.
PRODUCT GUIDE
CONVERSION MODES
PART NUMBER
LTC1091
LTC1092
LTC1093
LTC1094
#CHANNELS
2
1
6
8
UNIPOLAR
q
q
q
q
q
q
q
q
q
q
q
BIPOLAR
2
U
U
W
W W
U
W
(Notes 1, 2)
Power Dissipation ............................................. 500mW
Operating Temperature Range
LTC1091/2/3/4AC, LTC1091/2/3/4C..... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec.)................ 300°C
TOP VIEW
CS 1
+IN 2
–IN 3
GND 4
N8 PACKAGE
8-LEAD PDIP
8
7
6
5
V
CC
CLK
D
OUT
V
REF
ORDER PART
NUMBER
LTC1092ACN8
LTC1092CN8
T
JMAX
= 110°C,
θ
JA
= 150°C/W (N)
TOP VIEW
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
1
2
3
4
5
6
7
8
9
20 DV
CC
19 AV
CC
18 CLK
17 CS
16 D
OUT
15 D
IN
14 REF
+
13 REF
–
12 AGND
11 V
–
N PACKAGE
20-LEAD PDIP
LTC1094ACN
LTC1094CN
DGND 10
T
JMAX
= 110°C,
θ
JA
= 150°C/W (N)
REDUCED SPAN
CAPABILITY
(SEPARATE V
REF
)
±
5V
CAPABILITY
Pin-for-Pin 10-Bit Upgrade of ADC0832
Pin-for-Pin 10-Bit Upgrade of ADC0831
LTC1091/LTC1092
LTC1093/LTC1094
RECO
V
CC
V
–
f
CLK
t
CYC
E DED OPERATI G CO DITIO S
CONDITIONS
LTC1093/LTC1094, V
CC
= 5V
V
CC
= 5V
LTC1091
LTC1092
LTC1093/LTC1094
LTC1091A/LTC1092A/LTC1093A/LTC1094A
LTC1091/LTC1092/LTC1093/LTC1094
MIN
MAX
4.5
– 5.5
0.01
15 CLK Cycles
+ 2µs
12 CLK Cycles
+ 2µs
18 CLK Cycles
+ 2µs
150
1
400
0.8
1
2
15
12
18
ns
µs
ns
µs
µs
µs
CLK Cycles
CLK Cycles
CLK Cycles
10
0
0.5
UNITS
V
V
MHz
SYMBOL PARAMETER
Supply Voltage
Negative Supply Voltage
Clock Frequency
Total Cycle Time
t
hDI
t
suCS
t
suDI
t
WHCLK
t
WLCLK
t
WHCS
t
WLCS
Hold Time, D
IN
Alter SCLK↑
Setup Time CS↓ Before CLK↑
Setup Time D
IN
Stable Before CLK↑
CLK High Time
CLK Low Time
CS Low Time During Data Transfer
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
LTC1091
LTC1092
LTC1093/LTC1094
CS High Time Between Data Transfer Cycles V
CC
= 5V
CONVERTER AND
MULTIPLEXER
CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C. (Note 3)
LTC1091A/LTC1092A
LTC1093A/LTC1094A
MIN
TYP
MAX
q
q
q
q
q
PARAMETER
Offset Error
Linearity Error
Full-Scale Error
Total Unadjusted Error
Reference Input Resistance
Analog and REF Input Range
On-Channel Leakage Current
(Note 8)
CONDITIONS
(Note 4)
(Notes 4, 5)
(Note 4)
V
REF
= 5.000V (Notes 4, 6)
LTC1092/LTC1093/LTC1094
V
REF
= 5V
(Note 7)
On-Channel = 5V
Off-Channel = 0V
On-Channel = 0V
Off-Channel = 5V
q
q
q
q
5
Off-Channel Leakage Current
(Note 8)
On-Channel = 5V
Off-Channel = 0V
On-Channel = 0V
Off-Channel = 5V
U
U
U
W U
U WW
U
LTC1091/LTC1092
LTC1093/LTC1094
MIN
TYP
MAX
±0.5
±0.5
±2.0
5
10
UNITS
LSB
LSB
LSB
LSB
kΩ
V
±0.5
±0.5
±1.0
±1.0
10
(V
–
) – 0.05V to V
CC
+ 0.05V
1
–1
–1
1
1
–1
–1
1
µA
µA
µA
µA
3
LTC1091/LTC1092
LTC1093/LTC1094
AC CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C. (Note 3)
LTC1091A/LTC1092A/LTC1093A/LTC1094A
LTC1091/LTC1092/LTC1093/LTC1094
MIN
TYP
MAX
1.5
10
q
q
q
SYMBOL PARAMETER
t
SMPL
t
CONV
t
dDO
t
dis
t
en
t
hDO
t
f
t
r
C
IN
Analog Input Sample Time
Conversion Time
Delay Time, CLK↓ to D
OUT
Data Valid
Delay Time, CS↑ to D
OUT
Hi-Z
Delay Time, CLK↓ to D
OUT
Enabled
Time Output Data Remains Valid After SCLK↓
D
OUT
Fall Time
D
OUT
Rise Time
Input Capacitance
CONDITIONS
See Operating Sequence
See Operating Sequence
See Test Circuits
See Test Circuits
See Test Circuits
See Test Circuits
See Test Circuits
Analog Inputs On-Channel
Analog Inputs Off-Channel
Digital Inputs
UNITS
CLK Cycles
CLK Cycles
400
180
160
150
90
60
65
5
5
850
450
450
300
300
ns
ns
ns
ns
ns
ns
pF
pF
pF
q
q
DIGITAL A D DC ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C. (Note 3)
LTC1091A/LTC1092A/LTC1093A/LTC1094A
LTC1091/LTC1092/LTC1093/LTC1094
MIN
TYP
MAX
q
q
q
q
q
q
q
q
SYMBOL PARAMETER
V
IH
V
IL
I
IH
I
IL
V
OH
V
OL
I
OZ
I
SOURCE
I
SINK
I
CC
I
REF
I
–
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
Positive Supply Current
Reference Current
Negative Supply Current
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 ground with DGND, AGND,
GND and REF
–
wired together (unless otherwise noted). REF
–
is internally
connected to the AGND pin on the LTC1093. DGND, AGND, REF
–
and V
–
are internally connected to the GND pin on the LTC1091/LTC1092.
Note 3:
V
CC
= 5V, V
REF +
= 5V, V
REF –
= 0V, V
–
= 0V for unipolar mode and
– 5V for bipolar mode, CLK = 0.5MHz unless otherwise specified.
Note 4:
These specs apply for both unipolar (LTC1091/LTC1092/LTC1093/
LTC1094) and bipolar (LTC1093/LTC1094 only) modes. In bipolar mode,
one LSB is equal to the bipolar input span (2V
REF
) divided by 1024. For
example, when V
REF
= 5V, 1LSB (bipolar) = 2(5V)/1024 = 9.77mV.
Note 5:
Linearity error is specified between the actual end points of the
A/D transfer curve.
4
U
CONDITIONS
V
CC
= 5.25V
V
CC
= 4.75V
V
IN
= V
CC
V
IN
= 0V
V
CC
= 4.75V, I
OUT
= 10µA
V
CC
= 4.75V, I
OUT
= 360µA
V
CC
= 4.75V, I
OUT
= 1.6mA
V
OUT
= V
CC
, CS High
V
OUT
= 0V, CS High
V
OUT
= 0V
V
OUT
= V
CC
LTC1091, CS High
LTC1092/LTC1093/LTC1094, CS High, REF
+
Open
LTC1092/LTC1093/LTC1094, V
REF
= 5V
LTC1093/LTC1094, CS High, V
–
= – 5V
q
q
q
q
UNITS
V
V
µA
µA
V
V
2.0
0.8
2.5
–2.5
2.4
4.7
4.0
0.4
3
–3
–10
10
1.5
1.0
0.5
1
3.5
2.5
1.0
50
V
µA
µA
mA
mA
mA
mA
mA
µA
Note 6:
Total unadjusted error includes offset, full scale, linearity,
multiplexer and hold step errors.
Note 7:
Two on-chip diodes are tied to each reference and analog input
which will conduct for reference or analog input voltages one diode drop
below V
–
or one diode drop above V
CC
. Be careful during testing at low
V
CC
levels (4.5V), as high level reference or analog inputs (5V) can cause
this input diode to conduct, especially at elevated temperatures, and cause
errors for inputs near full scale. This spec allows 50mV forward bias of
either diode. This means that as long as the reference or analog input does
not exceed the supply voltage by more than 50mV, the output code will be
correct. To achieve an absolute 0V to 5V input voltage range will therefore
require a minimum supply voltage of 4.950V over initial tolerance,
temperature variations and loading.
Note 8:
Channel leakage current is measured after the channel selection.
LTC1091/LTC1092
LTC1093/LTC1094
TYPICAL PERFOR A CE CHARACTERISTICS
Change in Offset Error vs
Temperature
0.6
0.6
V
CC
(V
REF
) = 5V
f
CLK
= 500kHz
MAGNITUDE OF OFFSET CHANGE (LSB)
0.5
0.4
0.3
0.2
0.1
0
–50
0.5
0.4
0.3
0.2
0.1
0
–50
V
CC
(V
REF
) = 5V
f
CLK
= 500kHz
MAGNITUDE OF FULL-SCALE CHANGE (LSB)
MAGNITUDE OF LINEARITY CHANGE (LSB)
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
Digital Input Logic Threshold vs
Supply Voltage
4
D
OUT
DELAY TIME FROM SCLK↓ (ns)
D
OUT
DELAY TIME FROM SCLK↓ (ns)
T
A
= 25°C
3
LOGIC THRESHOLD (V)
2
1
0
4
5
6
7
8
SUPPLY VOLTAGE (V)
Maximum Clock Rate vs
Temperature
3.0
MAXIMUM CLK FREQUENCY* (MHz)
MAXIMUM CLK FREQUENCY* (MHz)
3.0
V
CC
= 5V
2.5
2.0
1.5
1.0
0.5
0
–50
2.5
2.0
1.5
1.0
0.5
0
4
5
6
7
8
SUPPLY VOLTAGE (V)
9
10
MINIMUM CLK FREQUENCY** (MHz)
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
*MAXIMUM CLK FREQUENCY REPRESENTS THE HIGHEST FREQUENCY AT WHICH CLK CAN
BE OPERATED (WITH 50% DUTY CYCLE) WHILE STILL PROVIDING 100ns SETUP TIME FOR
THE DEVICE RECEIVING THE D
OUT
DATA.
U W
1091/2/3/4 G01
Change in Linearity Error vs
Temperature
0.6
0.5
0.4
0.3
0.2
0.1
Change in Full-Scale Error vs
Temperature
V
CC
(V
REF
) = 5V
f
CLK
= 500kHz
125
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
125
0
–50
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
125
1091/2/3/4 G02
1091/2/3/4 G03
D
OUT
Delay Time vs Temperature
600
V
CC
= 5V
500
MSB-FIRST DATA
400
300
LSB-FIRST DATA
200
100
0
–50
600
500
400
D
OUT
Delay Time vs
Supply Voltage
T
A
= 25°C
MSB-FIRST DATA
300
200
100
0
LSB-FIRST DATA
9
10
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
125
4
5
6
7
8
SUPPLY VOLTAGE (V)
9
10
1091/2/3/4 G04
1091/2/3/4 G05
1091/2/3/4 G06
Maximum Clock Rate vs
Supply Voltage
0.3
Minimum Clock Rate vs
Temperature
V
CC
= 5V
0.25
0.20
0.15
0.10
0.05
0
–50
T
A
= 25°C
125
–25
25
50
75 100
0
AMBIENT TEMPERATURE (°C)
125
1091/2/3/4 G07
1091/2/3/4 G08
1091/2/3/4 G09
**AS THE CLK FREQUENCY IS DECREASED FROM 500kHz, MINIMUM CLK FREQUENCY
(∆ERROR
≤
0.1LSB) REPRESENTS THE FREQUENCY AT WHICH A 0.1LSB SHIFT IN ANY
CODE TRANSITION FROM ITS 500kHz VALUE IS FIRST DETECTED.
5
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