Stand-Alone, 10-Channel, 10-Bit System Monitors

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27

Transfer Function

Figure 10 shows the nominal transfer function for sin-

gle-ended or differential unipolar configured inputs,

Figure 11 illustrates the transfer function for differential

bipolar conversions, and Figure 12 shows temperature

conversions. Code transitions occur halfway between

successive-integer LSB values. Output coding is bina-

ry, with 1 LSB = 2.44mV (MAX1153) or 4mV (MAX1154)

for unipolar and bipolar operation, and 1 LSB = +0.5

°C

(MAX1153/MAX1154) for temperature measurements.

For unipolar operation, the 0 code level transition is at

Layout, Grounding, and Bypassing

For best performance, use PC boards. Do not use wire-

wrap boards. Board layout should ensure that digital

and analog signal lines are separated from each other.

Do not run analog and digital (especially clock) signals

parallel to one another or run digital lines underneath

the MAX1153/MAX1154 package. High-frequency

supply-noise rejection. If the power supply is very

noisy, connect a 10

Ω resistor in series with the supply

to improve power-supply filtering.

Definitions

Integral Nonlinearity

Integral nonlinearity is the deviation of the values on the

actual transfer function from a straight line. This straight

line can be either a best-straight-line fit or a line drawn

between the end points of the transfer function, once off-

set and gain errors have been corrected. The static lineari-

ty parameters for the MAX1153/MAX1154 are measured

using the end-point-fit method. INL is specified as the

maximum deviation in LSBs.

Differential Nonlinearity (DNL)

Differential nonlinearity 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.

Offset Error

The offset error is the difference between the ideal and

the actual analog input value at the first transition of the

ADC, usually from digital code 0 to code 1 for straight

binary output. For the MAX1153/MAX1154, the transi-

tion between code 0 and code 1 should occur at an

input voltage of 1/2 LSB, or 1.22mV for the MAX1153

and 2mV for the MAX1154.

OUTPUT CODE

011....111

TEMPERATURE

°C

011....110

000....001

111....101

100....001

100....000

111....111

111....110

000....000

0

000....010

-256

°C

+255.5

°C

Figure 12. Temperature Transfer Function

OUTPUT CODE

011....111

INPUT VOLTAGE (LSB)

011....110

000....001

111....101

100....001

100....000

111....111

111....110

000....000

0

000....010

-FS

+FS - 1 LSB

FS =

ZS = 0

2

-FS =

2

1 LSB =

1024