4-/6-/8-Channel, 16-Bit,

Simultaneous-Sampling ADCs

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15

Typical Application Circuits

Power-Grid Protection

Figure 10 shows a typical power-grid protection application.

DSP Motor Control

Figure 11 shows a typical DSP motor control application.

Definitions

Integral Nonlinearity (INL)

INL is the deviation of the values on an actual transfer

function from a straight line. For these devices, this

straight line is a line drawn between the end points of

the transfer function, once offset and gain errors have

been nullified.

Differential Nonlinearity (DNL)

DNL is the difference between an actual step width and

the ideal value of 1 LSB. For these devices, the DNL of

each digital output code is measured and the worst-

case value is reported in the

Electrical Characteristics

table. A DNL error specification of greater than -1 LSB

guarantees no missing codes and a monotonic transfer

function for an SAR ADC. For example, -0.9 LSB guaran-

tees no missing code while -1.1 LSB results in missing

code.

Offset Error

For the MAX11047/MAX11048/MAX11049, the offset

error is defined at code transition 0x0000 to 0x0001 in

offset binary encoding and 0x8000 to 0x8001 for two’s

complement encoding. The offset code transitions

should occur with an analog input voltage of exactly 0.5

is defined as the deviation between the actual analog

input voltage required to produce the offset code transi-

tion and the ideal analog input of 0.5 x (5/4.096) x

Gain Error

Gain error is defined as the difference between the

change in analog input voltage required to produce a

top code transition minus a bottom code transition, sub-

tracted from the ideal change in analog input voltage

MAX11047/MAX11048/MAX11049, top code transition

is 0x7FFE to 0x7FFF in two’s complement mode and

0xFFFE to 0xFFFF in offset binary mode. The bottom

code transition is 0x8000 and 0x8001 in two’s comple-

ment mode and 0x0000 and 0x0001 in offset binary

mode. For the MAX11047/MAX11048/MAX11049, the

analog input voltage to produce these code transitions

is measured and the gain error is computed by sub-

measurement.

0

FS/2

7FFF

0001

0000

8000

8001

FFFE

INPUT VOLTAGE (LSB)

FFFF

FULL-SCALE

TRANSITION

+FS

7FFE

LSB =

FS

65536

FS =

4.096

CODE =

- 32768,

4.096

5

Figure 8. Two’s Complement Transfer Function

FULL-SCALE

TRANSITION

FFFF

8001

8000

0000

0001

7FFE

INPUT VOLTAGE (LSB)

7FFF

FS/2

0

+FS

FFFE

LSB =

FS

65536

FS =

4.096

CODE =

,

4.096

5

Figure 9. Offset-Binary Transfer Function