Datasheet

MAX11190 4-Channel, Dual, Simultaneous Sampling,
2.2V to 3.6V, 12-Bit, 3Msps SAR ADC in Tiny
3mm x 3mm TQFN Package
www.maximintegrated.com
Maxim Integrated │ 13
ADC Transfer Function
The output format is straight binary. The code transitions
midwaybetween successiveintegerLSB valuessuch as
0.5LSB,1.5LSB,etc.TheLSBsizeisV
REF
/2
12
. The ideal
transfer characteristic is shown in Figure 9.
Operation Modes
The IC offers two modes of operation: normal mode and
power-down mode. The logic state of the CS signal dur-
ing a conversion activates these modes. The power-down
mode can be used to optimize power dissipation with
respect to sample rate.
Normal Mode
In normal mode, the device is powered up at all times,
thereby achieving its maximum throughput rates. Figure 6
shows the timing diagram of this device in normal mode.
The falling edge of CS samples the analog input signal,
starts a conversion, and frames the serial-data transfer.
To remain in normal mode, keep CS low until the falling
edge of the 10th SCLK cycle. Pulling CS high after the
10th SCLK falling edge keeps the part in normal mode.
However, pulling CS high before the 10th SCLK falling
edge terminates the conversion, both DOUTA/DOUTBs go
into high-impedance mode, and the device enters power-
down mode. See Figure 7.
Power-Down Mode
In power-down mode, all bias circuitry is shut down draw-
ing typically only 2.6µA of leakage current. To save power,
put the device in power-down mode between conver-
sions. Using the power-down mode between conversions
is ideal for saving power when sampling the analog input
infrequently.
Entering Power-Down Mode
To enter power-down mode, drive CS high between the
2ndand 10thfallingedges ofSCLK(see Figure 7). By
pulling CS high, the current conversion terminates and
both DOUTA/DOUTB enter high impedance.
Figure 6. Normal Mode
Figure 7. Entering Power-Down Mode
12345678910111213141516SCLK
PULL CS HIGH AFTER THE 10TH SCLK FALLING EDGEKEEP CS LOW UNTIL AFTER THE 10TH SCLK FALLING EDGE
CS
DOUTA
DOUTB
VALID DATA
HIGH
IMPEDANCE
HIGH
IMPEDANCE
12345678910111213141
51
6
HIGH
IMPEDANCE
INVALID
DATA
SCLK
CS
DOUTA
DOUTB
INVALID DATA OR HIGH IMPEDANC
EH
IGH IMPEDANCE
PULL CS HIGH AFTER THE 2ND AND BEFORE THE 10TH SCLK FALLING EDGE