MAX1295 Datasheet, PDF (13/20 Pages) Maxim Integrated Products – 265ksps, +3V, 6-/2-Channel, 12-Bit ADCs with +2.5V Reference and Parallel Interface

265ksps, +3V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
ACQUISITION STARTS
t_CP
ACQUISITION ENDS
CONVERSION STARTS
CLK
t_CWS
t_CH
t_CL
WR
t_CWH
ACQMOD = "0"
ACQUISITION STARTS
WR GOES HIGH WHEN CLK IS HIGH.
ACQUISITION ENDS
CONVERSION STARTS
CLK
WR
ACQMOD = "0"
WR GOES HIGH WHEN CLK IS LOW.
Figure 6a. External Clock and WR Timing (Internal Acquisition Mode)
ACQUISITION STARTS
ACQUISITION ENDS
CONVERSION STARTS
CLK
t_DH
WR
ACQMOD = "1"
WR GOES HIGH WHEN CLK IS HIGH
t_CWS
ACQMOD = "0"
ACQUISITION STARTS
ACQUISITION ENDS
CONVERSION STARTS
CLK
t_DH
t_CWH
WR
ACQMOD = "1"
WR GOES HIGH WHEN CLK IS LOW
ACQMOD = "0"
Figure 6b. External Clock and WR Timing (External Acquisition Mode)
External Clock Mode
To select the external clock mode, bits D6 and D7 of
the control byte must be set to zero. Figure 6 shows the
clock and WR timing relationship for internal (Figure 6a)
and external (Figure 6b) acquisition modes with an
external clock. For proper operation, a 100kHz to
4.8MHz clock frequency with 30% to 70% duty cycle is
recommended. Operating the MAX1295/MAX1297 with
clock frequencies lower than 100kHz is not recommend-
ed because the resulting voltage droop across the hold
capacitor in the T/H stage will degrade performance.
Digital Interface
The input and output data are multiplexed on a three-
state parallel interface (I/O) that can easily be inter-
faced with standard µPs. The signals CS, WR, and RD
control the write and read operations. CS represents
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