MAX192 Maxim, MAX192 Datasheet - Page 15

• Manufacturer Part Number: MAX192
• Description: Low-Power / 8-Channel / Serial 10-Bit ADC
• Manufacturer: Maxim

You can save power by placing the converter in a
low-current shutdown state between conversions.
Select full power-down or fast power-down mode via
bits 1 and 0 of the DIN control byte with SHDN either
high or floating (see Tables 3 and 6). Pull SHDN low at
any time to shut down the converter completely. SHDN
overrides bits 1 and 0 of DIN word (see Table 7).
Full power-down mode turns off all chip functions that
draw quiescent current, typically reducing I
Figure 12a. Timing Diagram Power-Down Modes, External Clock
Figure 12b. Timing Diagram Power-Down Modes, Internal Clock
CLOCK
MODE
MODE
DOUT
SHDN
CLOCK
MODE
SSTRB
MODE
DOUT
DIN
DIN
INTERNAL
S X X X X X 1 1
S X X X X X 1 0
______________________________________________________________________________________
Choosing Power-Down Mode
SETS EXTERNAL
CLOCK MODE
(10 + 2 DATA BITS)
SETS INTERNAL
CLOCK MODE
CONVERSION
DATA VALID
POWERED UP
Power-Down
POWERED UP
DD
EXTERNAL
DATA VALID
S
to 2µA.
X
X
X
X
INTERNAL CLOCK MODE
X
0 1
SETS FAST
POWER-DOWN
MODE
S
X
(10 + 2 DATA BITS)
X
Fast power-down mode turns off all circuitry except the
bandgap reference. With the fast power-down mode, the
supply current is 30µA. Power-up time can be shortened
to 5µs in internal compensation mode.
In both software shutdown modes, the serial interface
remains operational, however, the ADC will not convert.
Table 5 illustrates how the choice of reference-buffer
compensation and power-down mode affects both
power-up delay and maximum sample rate.
In external compensation mode, the power-up time is
20ms with a 4.7µF compensation capacitor when the
capacitor is fully discharged. In fast power-down, you
can eliminate start-up time by using low-leakage capaci-
Low-Power, 8-Channel,
DATA VALID
X
X
X
0 0
SETS FULL
POWER-DOWN
POWER-DOWN
CONVERSION
SETS EXTERNAL
FAST
Serial 10-Bit ADC
CLOCK MODE
S
X X X X X
POWERED UP
1 1
DATA VALID
POWER-DOWN
VALID
FULL
DATA INVALID
EXTERNAL
POWER-
DOWN
FULL
S
POWERED
POWERED
UP
UP
15