LTC1098LCS8 Linear Technology, LTC1098LCS8 Datasheet - Page 19

• Manufacturer Part Number: LTC1098LCS8
• Description: IC A/D CONV 8BIT SRL IN/OUT8SOIC
• Manufacturer: Linear Technology

Specifications of LTC1098LCS8

• Number Of Bits: 8
• Sampling Rate (per Second): 33k
• Data Interface: Serial
• Number Of Converters: 1
• Power Dissipation (max): 780µW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS INFORMATION
the data line and drive it low on the 4th falling CLK edge
after the start bit is received (see Figure 3). Therefore the
processor port line must be switched to an input before
this happens, to avoid a confl ict.
In the Typical Applications section, there is an example of
interfacing the LTC1098(L) with D
to the Intel 8051 MPU.
ACHIEVING MICROPOWER PERFORMANCE
With typical operating currents of 40μA and automatic
shutdown between conversions, the LTC1096/LTC1098
achieves extremely low power consumption over a wide
range of sample rates (see Figure 4). In systems that
convert continuously, the LTC1096/LTC1098 will draw
DATA (D
Figure 4. Automatic Power Shutdown Between Conversions
Allows Power Consumption to Drop with Sample Rate
IN
/D
OUT
CLK
1000
CS
100
10
)
1
0.1
T
V
A
CC
= 25°C
= 5V
Sample Rate, f
1
MPU CONTROLS DATA LINE AND SENDS
SAMPLE
Figure 3. LTC1098(L) Operation with D
MUX ADDRESS TO LTC1098(L)
START
IN
10
1
(kHz)
and D
10968 F04
OUT
SGL/DIFF
100
AND BEFORE THE 4TH FALLING CLK
DATA LINE AFTER 4TH RISING CLK
tied together
2
PROCESSOR MUST RELEASE
ODD/SIGN
3
its normal operating power continuously. Figure 5 shows
that the typical current varies from 40μA at clock rates
below 50kHz to 100μA at 500kHz. Several things must
be taken into account to achieve such a low power
consumption.
Shutdown
Figures 1 and 2 show the operating sequence of the
LTC1096/LTC1098. The converter draws power when the
CS pin is low and powers itself down when that pin is high.
If the CS pin is not taken to ground when it is low and not
taken to supply voltage when it is high, the input buffers
MSBF BIT LATCHED
BY LTC1098(L)
Figure 5. After a Conversion, When the Microprocessor
Drives CS High, the ADC Automatically Shuts Down Until the
Next Conversion. The Supply Current, Which Is Very Low
During cConversions, Drops to Zero in Shutdown
IN
MSBF
and D
4
0.002
OUT
140
120
100
80
60
40
20
0
100
Tied Together
T
V
LTC1098(L) TAKES CONTROL OF
DATA LINE ON 4TH FALLING CLK
A
CC
SUPPLY CURRENT vs CLOCK RATE FOR
= 25°C
LTC1098(L) CONTROLS DATA LINE AND SENDS
LTC1096/LTC1096L
LTC1098/LTC1098L
= 5V
ACTIVE AND SHUTDOWN MODES
ACTIVE (CS LOW)
1k
CLOCK FREQUENCY (Hz)
SHUTDOWN (CS HIGH)
A/D RESULT BACK TO MPU
B7
10k
100k
B6
10968 F05
1M
• • •
19
10968 F03
10968fc