MAX1246 Maxim, MAX1246 Datasheet - Page 14

• Manufacturer Part Number: MAX1246
• Description: +2.7V / Low-Power / 4-Channel / Serial 12-Bit ADCs in QSOP-16
• Manufacturer: Maxim

The fastest the MAX1246/MAX1247 can run with CS held
low between conversions is 15 clocks per conversion.
Figure 10a shows the serial-interface timing necessary to
perform a conversion every 15 SCLK cycles in external
clock mode. If CS is tied low and SCLK is continuous,
guarantee a start bit by first clocking in 16 zeros.
+2.7V, Low-Power, 4-Channel,
Serial 12-Bit ADCs in QSOP-16
Figure 9. Internal Clock Mode SSTRB Detailed Timing
Figure 10a. External Clock Mode, 15 Clocks/Conversion Timing
Figure 10b. External Clock Mode, 16 Clocks/Conversion Timing
14
DOUT
SCLK
DIN
SSTRB
CS
DOUT
SCLK
SSTRB
DIN
CS
______________________________________________________________________________________
SCLK
DOUT
CS
NOTE: FOR BEST NOISE PERFORMANCE, KEEP SCLK LOW DURING CONVERSION.
S
1
S
1
CONTROL BYTE 0
PD0 CLOCK IN
CONTROL BYTE 0
t
CSH
8
8
t
B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
SSTRB
B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
CONVERSION RESULT 0
t
CONV
CONVERSION RESULT 0
15
S
1
16
Most microcontrollers (µCs) require that conversions
occur in multiples of 8 SCLK clocks; 16 clocks per con-
version is typically the fastest that a µC can drive the
MAX1246/MAX1247. Figure 10b shows the serial-
interface timing necessary to perform a conversion every
16 SCLK cycles in external clock mode.
CONTROL BYTE 1
S
1
CONTROL BYTE 1
t
SCK
8
B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
8
CONVERSION RESULT 1
t
CSS
15
CONVERSION RESULT 1
B11 B10 B9 B8
S
1
CONTROL BYTE 2
t
DO
16