Rainbow Electronics MAX1081 - Manual (Page 10)

MAX1080/MAX1081
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
10 ______________________________________________________________________________________
Pin Description
Positive Supply Voltage V DD2 19
Input to the Reference-Buffer Amplifier. To disable the reference-buffer amplifier, connect REFADJ to
V
DD1
.
REFADJ 12
Serial Strobe Output. SSTRB pulses high for one clock period before the MSB decision. High imped-
ance when CS is high.
SSTRB 15
Serial Data Input. Data is clocked in at SCLK’s rising edge. DIN 16
Active-Low Chip Select. Data will not be clocked into DIN unless CS is low. When CS is high, DOUT
and SSTRB are high impedance.
CS 17
Serial Clock Input. Clocks data in and out of serial interface and sets the conversion speed. (Duty
cycle must be 40% to 60%.)
SCLK 18
Reference-Buffer Output/ADC Reference Input. Reference voltage for analog-to-digital conversion.
In internal reference mode, the reference buffer provides a 2.500V nominal output, externally
adjustable at REFADJ. In external reference mode, disable the internal buffer by pulling REFADJ to
V
DD1 .
REF 11
Analog and Digital Ground GND 13
Serial Data Output. Data is clocked out at SCLK’s rising edge. High impedance when CS is high. DOUT 14
Active-Low Shutdown Input. Pulling SHDN low shuts down the device, reducing supply current to 2µA
(typ).
SHDN 10
Ground Reference for Analog Inputs. COM sets zero-code voltage in single-ended mode. Must be
stable to ±0.5LSB.
COM 9
PIN
Sampling Analog Inputs CH0–CH7 1–8
FUNCTION NAME
V DD2
6k
GND
DOUT
C
LOAD
20pF
C
LOAD
20pF
GND
6k
DOUT
a) High-Z to V OH and V OL to V OH b) High-Z to V OL and V OH to V OL
V
DD2
6k
GND
DOUT
C
LOAD
20pF
C
LOAD
20pF
GND
6k
DOUT
a) V OH to High-Z b) V OL to High-Z
Figure 1. Load Circuits for Enable Time Figure 2. Load Circuits for Disable Time
Positive Supply Voltage V DD1 20