MAX1402EVKIT Maxim Integrated Products, MAX1402EVKIT Datasheet - Page 26

• Manufacturer Part Number: MAX1402EVKIT
• Description: EVAL KIT FOR MAX1402
• Manufacturer: Maxim Integrated Products

Specifications of MAX1402EVKIT

• Number Of Adc's: 1
• Number Of Bits: 18
• Sampling Rate (per Second): 480
• Data Interface: Serial
• Inputs Per Adc: 6 Single Ended
• Input Range: ±VREF/2
• Power (typ) @ Conditions: 26.7mW @ 480SPS
• Voltage Supply Source: Analog and Digital
• Operating Temperature: 0°C ~ 70°C
• Utilized Ic / Part: MAX1402
• Interface Type: SMA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: MAX1402

ensuring that REFIN+ is more positive than REFIN-.
REFIN+ and REFIN- must be between AGND and V+.
The MAX1402 is specified with a +2.5V reference when
operating with a +5V analog supply (V+).
The MAX1402 performs analog-to-digital conversion
using a single-bit, second-order, switched-capacitor
modulator. A single comparator within the modulator
quantizes the input signal at a much higher sample rate
than the bandwidth of the signal to be converted. The
quantizer then presents a stream of 1s and 0s to the
digital filter for processing, to remove the frequency-
shaped quantization noise.
The MAX1402 modulator provides 2nd-order frequency
shaping of the quantization noise resulting from the sin-
gle bit quantizer. The modulator is fully differential for
maximum signal-to-noise ratio and minimum suscepti-
bility to power-supply noise.
The modulator operates at one of a total of eight differ-
ent sampling rates (f
frequency (f
modulator frequency control bits MF1 and MF0. Power
dissipation is optimized for each of these modes by
controlling the bias level of the modulator. Table 15
shows the input and reference sample rates.
A programmable gain amplifier (PGA) with a user-
selectable gain of x1, x2, x4, x8, x16, x32, x64, or x128
(Table 6) precedes the modulator. Figure 7 shows the
default bipolar transfer function with the following illus-
trated codes: 1) PGA = 0, DAC = 0; 2) PGA = 3, DAC =
0; or 3) PGA = 3, DAC = 3.
+5V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
Table 14. R
Mode—All Modulator Sampling Frequencies (MF1, MF0 = XX); X2CLK = 0; CLKIN =
2.4576MHz
26
PGA GAIN
______________________________________________________________________________________
128
16
32
64
1
2
4
8
CLKIN
EXT
), the X2CLK bit, the CLK bit, and the
, C
M
C
EXT
) determined by the master clock
EXT
10
10
10
10
10
10
10
10
= 0pF
Values for Less than 16-Bit Gain Error in Buffered (BUFF = 1)
C
EXT
10
10
10
10
10
10
10
10
= 50pF
Modulator
PGA
EXTERNAL RESISTANCE R
C
EXT
= 100pF
10
10
10
10
10
10
10
10
Tables 16a and 16b show the rms noise for typical out-
put frequencies (notches) and -3dB frequencies for the
MAX1402 with f
given are for the bipolar input ranges with V
+2.50V, with no buffer (BUFF = 0) and with the buffer
inserted (BUFF = 1). These numbers are typical and
are generated at a differential analog input voltage of 0.
Figure 8 shows graphs of Effective Resolution vs. Gain
and Notch Frequency. The effective resolution values
were derived from the following equation:
Figure 7. Effect of PGA and DAC Codes on the Bipolar
Transfer Function
FULL-SCALE 259522
MAX CODE 262144
MIDSCALE 131072
ZERO-SCALE 2621
C
EXT
= 500pF
10
10
10
10
10
10
10
10
EXT
CLKIN
(kΩ)
INPUT VOLTAGE RANGE
C
= 2.4576MHz. The numbers
EXT
DAC = +3
PGA = 3
= 1000pF
10
10
10
10
10
10
10
10
NEGATIVE DAC STEP
SHIFTS THE TRANSFER
FUNCTION TOWARD
THE POSITIVE RAIL.
PGA = 3
DAC = 0
Output Noise
C
PGA = 0
DAC = 0
EXT
= 5000pF
10
10
10
10
10
10
10
10
REF
=