Definitions, Pin configurations chip information, Rollover error – Rainbow Electronics MAX1499 User Manual

Page 29: Zero input reading, Gain error, Common-mode rejection, Power-supply rejection ratio

Definitions

INL

Integral nonlinearity (INL) is the deviation of the values on
an actual transfer function from a straight line. This straight
line is either a best-straight-line fit or a line drawn between
the end points of the transfer function, once offset and
gain errors have been nullified. INL for the MAX1497/
MAX1499 is measured using the endpoint method.

DNL

Differential nonlinearity (DNL) is the difference between
an actual step width and the ideal value of ±1 LSB. A
DNL error specification of less than ±1 LSB guarantees
no missing codes and a monotonic transfer function.

Rollover Error

Rollover error is defined as the absolute-value differ-
ence between a near positive full-scale reading and
near negative full-scale reading. Rollover error is tested
by applying a full-scale positive voltage, swapping
AIN+ and AIN-, and adding the results.

Zero Input Reading

Ideally, with AIN+ connected to AIN-, the MAX1497/
MAX1499 digital ADC result is 0000h. Zero input read-
ing is the measured deviation from the ideal 0x0000
and the actual measured point.

Gain Error

Gain error is the amount of deviation between the mea-
sured full-scale transition point and the ideal full-scale
transition point.

Common-Mode Rejection

Common-mode rejection (CMR) is the ability of a
device to reject a signal that is common to both input
terminals. The common-mode signal can be either an
AC or a DC signal or a combination of the two. CMR is
often expressed in decibels.

Normal-Mode 50Hz and 60Hz Rejection

(Simultaneously)

Normal-mode rejection is a measure of how much output
changes when a 50Hz and a 60Hz signal is injected into
only one of the differential inputs. The MAX1497/
MAX1499 sigma-delta converter uses its internal digital
filter to provide normal-mode rejection to both 50Hz and
60Hz power-line frequencies simultaneously.

Power-Supply Rejection Ratio

Power-supply rejection ratio (PSRR) is the ratio of the input
supply change (in volts) to the change in the converter
output (in volts). It is typically measured in decibels.

MAX1497/MAX1499

3.5- and 4.5-Digit, Single-Chip ADCs with LED

Drivers and µC Interface

______________________________________________________________________________________

SEGDP

SEGG

SEGF

VLED

SEGE

SEGD

DIG0

SEGC

SEGB

SEGA

DIG3

DIG2

GLED

DIG1

DOUT

SCLK

DIN

EOC

CLK

GND

AIN-

AIN+

SET

REF+

REF-

VNEG

SSOP/PDIP

TOP VIEW

MAX1497

TOP VIEW

MAX1499

TQFP

NEG

LOWBATT

LED_EN