In reality, there are other noise sources besides quanti-

zation noise: thermal noise, reference noise, clock jitter,

etc. SNR is computed by taking the ratio of the RMS

signal to the RMS noise, which includes all spectral

components minus the fundamental, the first five har-

monics, and the DC offset.

Signal-to-Noise Plus Distortion

Signal-to-noise plus distortion (SINAD) is the ratio of the

fundamental input frequency’s RMS amplitude to the

RMS equivalent of all the other ADC output signals.

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 full-

scale range of the ADC, calculate the effective number

of bits as follows:

Total Harmonic Distortion

Total harmonic distortion (THD) is the ratio of the RMS

sum of the first five harmonics of the input signal to the

fundamental itself. This is expressed as:

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 fre-

quency component.

Chip Information

TRANSISTOR COUNT: 15,383

PROCESS: BiCMOS

THD

=

×

































20

log

V+ V+ V

+ V

V

2

2

3

2

4

2

5

2

1

E

SINAD - 1.76

NOB

= 







602

.

SINAD db

Signal

Noise

Distortion

RMS

RMS

(

)

log

()

=×

+









20

14-Bit, 135ksps, Single-Supply ADCs with

Bipolar Analog Input Range

______________________________________________________________________________________

13

Ordering Information (continued)

PART

TEMP RANGE

PIN-PACKAGE

INPUT VOLTAGE

RANGE

INL (LSB)

MAX1157AEUI

-40°C to +85°C

28 TSSOP

0 to +10V

±1

MAX1157BEUI

-40°C to +85°C

28 TSSOP

0 to +10V

±2

MAX1159ACUI

0°C to +70°C

28 TSSOP

±10V

±1

MAX1159BCUI

0°C to +70°C

28 TSSOP

±10V

±2

MAX1159AEUI*

-40°C to +85°C

28 TSSOP

±10V

±1

MAX1159BEUI*

-40°C to +85°C

28 TSSOP

±10V

±2

MAX1175ACUI

0°C to +70°C

28 TSSOP

±5V

±1

MAX1175BCUI

0°C to +70°C

28 TSSOP

±5V

±2

MAX1175AEUI

-40°C to +85°C

28 TSSOP

±5V

±1

MAX1175BEUI

-40°C to +85°C

28 TSSOP

±5V

±2

*Future product—contact factory for availability.