MAX1403EAI+ Maxim Integrated Products, MAX1403EAI+ Datasheet - Page 24

• Manufacturer Part Number: MAX1403EAI+
• Description: IC ADC 18BIT LP 28-SSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1403EAI+

• Number Of Bits: 18
• Sampling Rate (per Second): 480
• Data Interface: QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 21.45mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Number Of Adc Inputs: 5
• Architecture: Delta-Sigma
• Conversion Rate: 4.8 KSPs
• Resolution: 18 bit
• Input Type: Voltage
• Interface Type: Serial
• Voltage Reference: External
• Supply Voltage (max): 3 V
• Maximum Power Dissipation: 21.45 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Input Signal Type: Pseudo-Differential, Differential
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
The MAX1403 provides a pair of input buffers to isolate
the inputs from the capacitive load presented by the
PGA/modulator (Figure 6). The buffers are chopper sta-
bilized to reduce the effect of their DC offsets and low-
frequency noise. Since the buffers can represent more
than 50% of the total analog power dissipation, they may
be shut down in applications where minimum power dis-
sipation is required and the capacitive input load is not a
24
Table 13c. R
Mode—4x Modulator Sampling Frequency (MF1, MF0 = 10 ); X2CLK = 0; CLKIN =
2.4576MHz
Table 13d. R
Mode—8x Modulator Sampling Frequency (MF1, MF0 = 11); X2CLK = 0; CLKIN =
2.4576MHz
Figure 6. Analog Input, Buffered Mode (BUFF = 1)
PGA GAIN
PGA GAIN
8, 16, 32,
8, 16, 32,
______________________________________________________________________________________
64, 128
64, 128
1
2
4
1
2
4
R
EXT
EXT
EXT
C
EXT
C
C
, C
, C
EXT
EXT
8.3
8.3
6.2
4.1
4.1
4.1
3.0
2.0
EXT
EXT
= 0pF
= 0pF
Values for Less than 16-Bit Gain Error in Unbuffered (BUFF = 0)
Values for Less than 16-Bit Gain Error in Unbuffered (BUFF = 0)
C
PIN
R
MUX
C
C
EXT
EXT
3.7
3.7
3.2
2.5
1.8
1.8
1.5
1.2
= 50pF
= 50pF
Input Buffers
C
ST
EXTERNAL RESISTANCE, R
EXTERNAL RESISTANCE, R
R
IN
C
C
EXT
EXT
0.88
2.4
2.4
2.2
1.8
1.2
1.2
1.1
= 100pF
= 100pF
concern. Disable the buffers in applications where the
inputs must operate close to AGND or V+.
When used in buffered mode, the buffers isolate the
inputs from the sampling capacitors. The sampling-
related gain error is dramatically reduced in this mode.
A small dynamic load remains from the chopper stabi-
lization. The multiplexer exhibits a small input leakage
current of up to 10nA. With high source resistances,
this leakage current may result in a DC offset.
C
AMP
C
C
EXT
EXT
0.72
0.72
0.67
0.60
0.35
0.35
0.32
0.29
= 500pF
= 500pF
EXT
EXT
(kΩ)
(kΩ)
C
SAMPLE
C
C
EXT
EXT
0.40
0.40
0.38
0.35
0.20
0.20
0.18
0.17
= 1000pF
= 1000pF
C
C
C
EXT
EXT
C
0.11
0.11
0.10
0.09
0.05
0.05
0.05
0.04
= 5000pF
= 5000pF