MAX1246/MAX1247
+2.7V, Low-Power, 4-Channel,
Serial 12-Bit ADCs in QSOP-16
14 ______________________________________________________________________________________
conversion already in progress. When internal clock
mode is selected, SSTRB does not go into a high-
impedance state when CS goes high.
Figure 9 shows the SSTRB timing in internal clock
mode. In this mode, data can be shifted in and out of
the MAX1246/MAX1247 at clock rates exceeding
2.0MHz if the minimum acquisition time (t
ACQ
) is kept
above 1.5µs.
Data Framing
The falling edge of CS does not start a conversion.
The first logic high clocked into DIN is interpreted as a
start bit and defines the first bit of the control byte. A
conversion starts on SCLK’s falling edge, after the eighth
bit of the control byte (the PD0 bit) is clocked into DIN.
The start bit is defined as follows:
The first high bit clocked into DIN with CS low any
time the converter is idle; e.g., after V
DD
is applied.
OR
The first high bit clocked into DIN after bit 5 of a con-
version in progress is clocked onto the DOUT pin.
If CS is toggled before the current conversion is com-
plete, the next high bit clocked into DIN is recognized as
a start bit; the current conversion is terminated, and a
new one is started.
