MCP3550-50-E/SN Microchip Technology, MCP3550-50-E/SN Datasheet - Page 19

• Manufacturer Part Number: MCP3550-50-E/SN
• Description: IC, ADC, 22BIT, 12.5SPS, SOIC-8
• Manufacturer: Microchip Technology

Specifications of MCP3550-50-E/SN

• Resolution (bits): 22bit
• Sampling Rate: 12.5SPS
• Input Channel Type: Differential
• Data Interface: 3-Wire, Serial
• Supply Voltage Range - Analog: 2.7V To 5.5V
• Supply Current: 120µA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.3
If a rising edge of Chip Select (CS) occurs during t
a subsequent conversion will not take place and the
device will enter low-power Shutdown mode after
t
Conversion mode. This operation is demonstrated in
Figure 5-3. Note that a falling edge of CS during the
same conversion that detected a rising edge, as in
Figure 5-2, will not initiate a new conversion. Once a
rising edge is seen, the device will enter Sleep, then
Shutdown mode. Once the device has been put into
Single Conversion mode, the data must be clocked out
in order for a new conversion to take place. A
subsequent falling edge on CS during Shutdown mode
will not initiate a new conversion, unless the prior
conversion data has been clocked out of the device.
After the final data bit has been clocked out on the 25th
clock, the SDO/RDY pin will go active-high.
5.3.1
At every falling edge of CS during the internal conver-
sion, the state of the internal conversion is latched on
the SDO/RDY pin to give ready or busy information. A
High state means the device is currently performing an
internal conversion and data cannot be clocked out. A
Low state means the device has finished its conversion
and the data is ready for retrieval on the falling edge of
SCK. This operation is demonstrated in Figure 5-4.
Note that the device has been put into Single
Conversion mode with the first rising edge of CS.
FIGURE 5-4:
Conversion Mode.
© 2005 Microchip Technology Inc.
CONV
SDO/RDY
Note:
Int. Osc
CS
completes. This is referred to as Single
Single Conversion Mode
READY FUNCTION OF SDO/RDY
PIN, SINGLE CONVERSION MODE
The Ready state is latched on each falling
edge of CS and will not dynamically
update if CS is held low. CS must be
toggled high through low.
t
CONV
RDY Functionality in Single
Hi-Z
CONV
,
5.4
If no rising edge of CS occurs during any given conver-
sion per Figure 5-2, a subsequent conversion will take
place and the contents of the previous conversion will
be overwritten. This operation is demonstrated in
Figure 5-5. Once conversion output data has started to
be clocked out, the output buffer is not refreshed until
all 24 bits have been clocked. A complete read must
occur in order to read the next conversion in this mode.
The subsequent conversion data to be read will then be
the most recent conversion. The conversion time is
fixed and cannot be shortened by the rising edge of CS.
This rising edge will place the part in Shutdown mode
and all conversion data will be lost.
The transfer of data from the SINC filter to the output
buffer is demonstrated in Figure 5-5. If the previous
conversion data is not clocked out of the device, it will
be lost and replaced by the new conversion. When the
device is in Continuous Conversion mode, the most
recent conversion data is always present at the output
register for data retrieval.
FIGURE 5-5:
Conversion Mode Data.
If a conversion is in process, it cannot be terminated
with the rising edge of CS. SDO/RDY must first
transition to a Low state, which will indicate the end of
conversion.
5.4.1
The device enters Continuous Conversion mode if no
rising edge of CS is seen during t
tive conversions ensue. SDO/RDY will be high,
indicating that a conversion is in process. When a
conversion is complete, SDO/RDY will change to a
Low state. With the Low state of SDO/RDY after this
first conversion, the conversion data can be accessed
with the combination of SCK and SDO/RDY. If the data
ready event happens during the clocking out of the
data, the data ready bit will be displayed after the
complete 24-bit word communication (i.e., the data
ready event will not interrupt a data transfer).
SCK & SDO/RDY
Int. Osc
CS
Continuous Conversion Mode
READY FUNCTION OF SDO/RDY
PIN IN CONTINUOUS CONVERSION
MODE
t
CONV
Conversion B data is clocked
out of the device here.
MCP3550/1/3
A
Most Current Continuous
t
CONV
B
CONV
DS21950C-page 19
and consecu-
t
CONV
C