MAX144 Maxim, MAX144 Datasheet - Page 11

• Manufacturer Part Number: MAX144
• Description: +2.7V / Low-Power / 2-Channel / 108ksps / Serial 12-Bit ADCs in 8-Pin MAX
• Manufacturer: Maxim

4) Pull CS/SHDN high at or after the 16th falling clock
5) With CS/SHDN high, wait at least 60ns (t
Data can be output in two 8-bit sequences or continu-
ously. The bytes will contain the result of the conversion
Figure 7. Detailed Serial-Interface Timing Sequence
Figure 8a. SPI Connections
Figure 8c. SPI/MICROWIRE Interface Timing Sequence (CPOL = CPHA = 0)
CS/SHDN
CS/SHDN
*WHEN CS/SHDN IS HIGH, DOUT = HIGH-Z
DOUT valid timing characteristic. Data should be
clocked into the µP on SCLK’s rising edge.
edge. If CS/SHDN remains low, trailing zeros will be
clocked out after the LSB.
starting a new conversion by pulling CS/SHDN low.
A conversion can be aborted by pulling CS/SHDN
high before the conversion ends; wait at least 60ns
before starting a new conversion.
DOUT*
DOUT
SCLK
SCLK
SPI
HIGH-2
t
SCLKS
MISO
SCK
I/O
SS
______________________________________________________________________________________
+2.7V, Low-Power, 2-Channel, 108ksps,
t
1
DV
SAMPLING INSTANT
V
DD
2
3
CHID D11
1ST BYTE READ
Serial 12-Bit ADCs in 8-Pin µMAX
4
CS/SHDN
SCLK
DOUT
MSB
t
CL
MAX144
MAX145
5
D10
CS
6
) before
t
CH
D9
7
D8
8
padded with three leading ones and the channel identi-
fication before the MSB. If the serial clock hasn’t been
idled after the last LSB and CS/SHDN is kept low,
DOUT sends trailing zeros.
When using SPI (Figure 8a) or MICROWIRE (Figure 8b)
interfaces, set CPOL = 0 and CPHA = 0. Conversion
begins with a falling edge on CS/SHDN (Figure 8c).
Two consecutive 8-bit readings are necessary to obtain
the entire 12-bit result from the ADC. DOUT data transi-
tions on the serial clock’s falling edge and is clocked
into the µP on SCLK’s rising edge. The first 8-bit data
stream contains three leading ones, the channel identi-
8b. MICROWIRE Connections
D7
MICROWIRE
9
D6
t
DO
I/O
SK
10
SI
D5
11
SPI and MICROWIRE Interface
2ND BYTE READ
D4
12
D3
13
D2
14
CS/SHDN
SCLK
DOUT
t
D1
TR
15
MAX144
MAX145
t
CS
LSB
D0
16
HIGH-2
HIGH-Z
11