MCP3002-I/SN Microchip Technology, MCP3002-I/SN Datasheet - Page 20

• Manufacturer Part Number: MCP3002-I/SN
• Description: IC ADC 10BIT 2.7V 2CH SPI 8-SOIC
• Manufacturer: Microchip Technology

Specifications of MCP3002-I/SN

• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Number Of Bits: 10
• Sampling Rate (per Second): 200k
• Data Interface: Serial, SPI™
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Architecture: SAR
• Conversion Rate: 200 KSPs
• Input Type: Voltage
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

MCP3002
FIGURE 6-2:
high).
6.2
When the MCP3002 initiates the sample period, charge
is stored on the sample capacitor. When the sample
period is complete, the device converts one bit for each
clock that is received. It is important for the user to note
that a slow clock rate will allow charge to bleed off the
sample cap while the conversion is taking place. At
85°C (worst case condition), the part will maintain
proper charge on the sample cap for 700 µs at
V
V
for the sample period and the 10 clocks for the actual
conversion must not exceed 700 µs. Failure to meet
this criteria may induce linearity errors into the
conversion outside the rated specifications.
6.3
If the signal source for the A/D Converter is not a low
impedance source, it will have to be buffered or
inaccurate conversion results may occur. It is also
recommended that a filter be used to eliminate any
signals that may be aliased back in to the conversion
results. This is illustrated in
op amp is used to drive, filter, and gain the analog input
of the MCP3002. This amplifier provides a low
impedance output for the converter input and a low-
pass filter, which eliminates unwanted high-frequency
noise.
DS21294D-page 20
DD
DD
MCU Transmitted Data
(Aligned with falling
= 2.7V and 1.5 ms at V
= 2.7V, the time it takes to transmit the 1.5 clocks
MCU Received Data
edge of clock)
(Aligned with rising
X = Don’t Care Bits
edge of clock)
Maintaining Minimum Clock Speed
Buffering/Filtering the Analog
Inputs
SCLK
D
OUT
D
CS
IN
SPI Communication with the MCP3002 using 8-bit segments (Mode 1,1: SCLK idles
X
1
X
Start
Bit
Data stored into MCU receive register
DD
1
Figure 6-3
2
HI-Z
after transmission of first 8 bits
X
SGL/
DIFF
= 5V. This means that at
3
X
ODD/
SIGN
4
X
MSBF
below where an
5
X
NULL
X
BIT
(Null)
6
0
X
B9
7
B9
X
B8
B8
8
X
B7
9
B7
Data stored into MCU receive register
X
B6
after transmission of second 8 bits
10
B6
Low-pass (anti-aliasing) filters can be designed using
Microchip’s interactive FilterLab
will calculate capacitor and resistors values, as well as,
determine the number of poles that are required for the
application. For more information on filtering signals,
see the application note AN699 “Anti-Aliasing Analog
Filters for Data Acquisition Systems.”
FIGURE 6-3:
Circuit (2 pole Active Filter).
V
Don’t Care
IN
X
B5
11
B5
R
X
B4
12
1
B4
X
B3
13
R
C
B3
C
2
1
2
X
B2
14
B2
X
B1
15
R
B1
MCP601
3
+
X
-
B0
R
16
B0
4
Typical Anti-Aliasing Filter
© 2008 Microchip Technology Inc.
MCU latches data from A/D Converter
on rising edges of SCLK
Data is clocked out of
A/D Converter on falling edges
®
IN+
IN-
software. FilterLab
MCP3002
10 µF
V
DD
1 µF