MAX1236 Datasheet, PDF (20/22 Pages) Maxim Integrated Products – 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
Effective Number of Bits
Effective number of bits (ENOB) indicates the global
accuracy of an ADC at a specific input frequency and
sampling rate. An ideal ADC’s error consists of quanti-
zation noise only. With an input range equal to the
ADC’s full-scale range, calculate the ENOB as follows:
ENOB = (SINAD - 1.76) / 6.02
Total Harmonic Distortion
Total harmonic distortion (THD) is the ratio of the RMS
sum of the input signal’s first five harmonics to the fun-
damental itself. This is expressed as:
THD
=

20
×
log





V₂₂
+

V₃₂ + V₄₂ +
V₁
V₅₂







where V₁ is the fundamental amplitude, and V₂ through
V₅ are the amplitudes of the 2nd- through 5th-order
harmonics.
Spurious-Free Dynamic Range
Spurious-free dynamic range (SFDR) is the ratio of the
RMS amplitude of the fundamental (maximum signal
component) to the RMS value of the next largest distor-
tion component.
Typical Operating Circuit
0.1µF
3.3V or 5V
V_DD
ANALOG
INPUTS
AIN0
AIN1
AIN3**/REF
MAX1236
MAX1237
MAX1238
MAX1239
C_REF
0.1µF
GND
*R_S
SDA
SCL
*R_S
5V
R_P
5V
R_P
µC
SDA
SCL
*OPTIONAL
**AIN11/REF (MAX1238/MAX1239)
TOP VIEW
Pin Configurations
AIN0 1
AIN1 2
AIN2 3
AIN3/REF 4
MAX1236
MAX1237
8 V_DD
7 GND
6 SDA
5 SCL
µMAX
AIN0 1
AIN1 2
AIN2 3
AIN3 4
AIN4 5
AIN5 6
AIN6 7
AIN7 8
MAX1238
MAX1239
QSOP
16 AIN8
15 AIN9
14 AIN10
13 AIN11/REF
12 V_DD
11 GND
10 SDA
9 SCL
Ordering Information (continued)
PART
TEMP
RANGE
PIN- I²C SLAVE INL
PACKAGE ADDRESS (LSB)
MAX1238EEE -40°C to +85°C 16 QSOP 0110101 ±1
MAX1238KEEE* -40°C to +85°C 16 QSOP 0110001 ±1
MAX1238LEEE* -40°C to +85°C 16 QSOP 0110011 ±1
MAX1238MEEE* -40°C to +85°C 16 QSOP 0110111 ±1
MAX1239EEE -40°C to +85°C 16 QSOP 0110101 ±1
MAX1239KEEE -40°C to +85°C 16 QSOP 0110001 ±1
MAX1239LEEE -40°C to +85°C 16 QSOP 0110011 ±1
MAX1239MEEE -40°C to +85°C 16 QSOP 0110111 ±1
*Future product—contact factory for availability.
Chip Information
MAX1236/MAX1237 TRANSISTORS COUNT: 11,362
MAX1238/MAX1239 TRANSISTORS COUNT: 12,956
PROCESS: BiCMOS
20 ______________________________________________________________________________________