MAX1108 Datasheet, PDF (9/20 Pages) Maxim Integrated Products – Single-Supply, Low-Power, 2-Channel, Serial 8-Bit ADCs

Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
Typical Operating Characteristics (continued)
(V_DD = +3.0V (MAX1108), V_DD = +5.0V (MAX1109); external conversion mode; f_SCLK = 500kHz; 50ksps; external reference; 1µF at
REF; T_A = +25°C; unless otherwise noted.)
INTEGRAL NONLINEARITY
vs. CODE
FFT PLOT
CONVERSION TIME vs. SUPPLY VOLTAGE
0.5
20
21.0
f_{CH_} = 9997Hz, 2Vp-p
0.4
0.3
0
f_SAMPLE = 53.25kHz
INTERNAL CONVERSION MODE
20.5
0.2
-20
20.0
0.1
0
-40
19.5
-0.1
-0.2
-60
19.0
-0.3
-0.4
-0.5
0
50 100 150 200 250 300
DIGITAL CODE
CONVERSION TIME vs. TEMPERATURE
25
24 INTERNAL CONVERSION MODE
23
-80
-100
0
5 10 15 20 25 30
FREQUENCY (kHz)
NORMALIZED REFERENCE VOLTAGE
vs. TEMPERATURE
1.0010
1.0005
18.5
18.0
0
1
2
3
4
5
6
SUPPLY VOLTAGE (V)
CHANNEL-TO-CHANNEL
CROSSTALK vs. FREQUENCY
0
-10 VCH_OFF = VREFp-p
-20
22
21
V_DD = 3V
1.0000
-30
-40
20
0.9995
-50
19
V_DD = 5V
-60
18
0.9990
-70
17
0.9985
-80
16
-90
15
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
0.9980
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
-100
0
5
10
15
20
25
FREQUENCY (kHz)
Pin Description
PIN
NAME
FUNCTION
1
V_DD
Positive Supply Voltage
2, 3 CH0, CH1 Sampling Analog Inputs
4
GND
Ground
5
REF
Reference voltage for analog-to-digital conversion (internal or external reference). Reference input for
external reference. Bypass internal reference with 1µF capacitor to GND.
6
COM
Common reference for analog inputs. Sets zero-code voltage in single-ended mode. Must be stable to
±0.5LSB during conversion.
7
CS
Active-Low Chip Select. Data is not clocked into DIN unless CS is low. When CS is high, DOUT is high
impedance.
8
DIN
Serial Data Input. Data is clocked in at the rising edge of SCLK.
9
DOUT
Serial Data Output. Data is clocked out on the falling edge of SCLK. High impedance when CS is high.
10
SCLK
Serial Clock Input. Clocks data in and out of serial interface. In external clock mode, SCLK also sets the
conversion speed.
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