MAX197 Maxim, MAX197 Datasheet - Page 12

• Manufacturer Part Number: MAX197
• Description: Multi-Range (10V / 5V / +10V / +5V) / Single +5V / 12-Bit DAS with 8+4 Bus Interface
• Manufacturer: Maxim

Select external clock mode by writing the control byte
with D7 = 0 and D6 = 0. Figure 8 shows CLK and WR
timing relationships in internal and external acquisition
modes, with an external clock. A 100kHz to 2.0MHz
Multi-Range (±10V, ±5V, +10V, +5V),
Single +5V, 12-Bit DAS with 8+4 Bus Interface
Figure 8a. External Clock and WR Timing (Internal Acquisition Mode)
Figure 8b. External Clock and WR Timing (External Acquisition Mode)
12
CLK
CLK
CLK
CLK
WR
WR
WR
WR
______________________________________________________________________________________
t
CWH
ACQMOD = "1"
ACQMOD = "1"
ACQMOD = "0"
ACQMOD = "0"
ACQUISITION STARTS
ACQUISITION STARTS
ACQUISITION STARTS
t
t
DH
DH
External Clock Mode
ACQUISITION STARTS
t
CWS
WR GOES HIGH WHEN CLK IS HIGH
WR GOES HIGH WHEN CLK IS LOW
WR GOES HIGH WHEN CLK IS HIGH
WR GOES HIGH WHEN CLK IS LOW
external clock with 45% to 55% duty cycle is required
for proper operation. Operating at clock frequencies
lower than 100kHz will cause a voltage droop across
the hold capacitor, and subsequently degrade perfor-
mance.
ACQUISITION ENDS
t
ACQUISITION ENDS
CWH
ACQMOD = "0"
ACQUISITION ENDS
ACQUISITION ENDS
ACQMOD = "0"
t
CWS
CONVERSION STARTS
CONVERSION STARTS
CONVERSION STARTS
CONVERSION STARTS