LTC1096 Linear Technology, LTC1096 Datasheet - Page 16

• Manufacturer Part Number: LTC1096
• Description: Micropower Sampling 8-Bit Serial I/O A/D Converters
• Manufacturer: Linear Technology

LTC1096/LTC1096L
LTC1098/LTC1098L
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 conflict.
In the Typical Applications section, there is an example of
interfacing the LTC1098(L) with D
gether to the Intel 8051 MPU.
ACHIEVING MICROPOWER PERFORMANCE
With typical operating currents of 40 A 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 its
16
A
DATA (D
PPLICATI
Figure 4. Automatic Power Shutdown Between Conversions
Allows Power Consumption to Drop with Sample Rate
IN
/D
OUT
CLK
CS
1000
100
)
10
1
0.1
T
V
A
CC
O
= 25°C
= V
SAMPLE FREQUENCY, f
REF
U
= 5V
S
1
I FOR ATIO
U
MPU CONTROLS DATA LINE AND SENDS
MUX ADDRESS TO LTC1098(L)
Figure 3. LTC1098(L) Operation with D
START
SMPL
10
1
LTC1096/98 • TPC03
IN
(kHz)
W
and D
SGL/DIFF
AND BEFORE THE 4TH FALLING CLK
DATA LINE AFTER 4TH RISING CLK
100
2
OUT
PROCESSOR MUST RELEASE
U
tied to-
ODD/SIGN
3
MSBF BIT LATCHED
normal operating power continuously. Figure 5 shows
that the typical current varies from 40 A at clock rates
below 50kHz to 100 A 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 of
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
MSBF
IN
4
and D
0.002
OUT
140
120
100
80
60
40
20
0
100
Tied Together
LTC1098(L) TAKES CONTROL OF
DATA LINE ON 4TH FALLING CLK
T
V
A
CC
LTC1098(L) CONTROLS DATA LINE AND SENDS
= 25°C
= 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
LTC1096/98 • F05
1M
• • •
LTC1-96/8 • F03