Datasheet

MCP3004/3008
DS21295D-page 20 © 2008 Microchip Technology Inc.
FIGURE 5-1: Communication with the MCP3004 or MCP3008.
FIGURE 5-2: Communication with MCP3004 or MCP3008 in LSB First Format.
CS
CLK
D
IN
D
OUT
D1D2
D0
HI-Z
Don’t Care
Null
Bit
B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 *
HI-Z
t
SAMPLE
t
CONV
SGL/
DIFF
Start
t
CYC
t
CSH
t
CYC
D2
SGL/
DIFF
Start
* After completing the data transfer, if further clocks are applied with CS low, the A/D converter will output LSB
first data, then followed with zeros indefinitely. See Figure 5-2 below.
** t
DATA
: during this time, the bias current and the comparator powers down while the reference input becomes
a high-impedance node.
t
DATA
**
t
SUCS
Null
Bit
B9
B8 B7 B6 B5 B4 B3 B2 B1 B0 B1 B2 B3 B4 B5 B6 B7 B8 B9
CS
CLK
D
OUT
HI-Z
HI-Z
(MSB)
t
CONV
t
DATA
**
Power Down
t
SAMPLE
Start
SGL/
DIFF
D
IN
t
CYC
t
CSH
D0D1D2
* After completing the data transfer, if further clocks are applied with CS low, the A/D converter will output zeros
indefinitely.
** t
DATA
: During this time, the bias circuit and the comparator powers down while the reference input becomes
a high-impedance node, leaving the CLK running to clock out LSB first data or zeroes.
t
SUCS
Don’t Care
*