1.8V, 12-Bit, 170Msps ADC for

Broadband Applications

18

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Noise Power Ratio (NPR)

NPR is commonly used to characterize the return path of

cable systems where the signals are typically individual

quadrature amplitude-modulated (QAM) carriers with a

frequency spectrum similar to noise. Numerous such

carriers are operated in a continuous spectrum, generat-

ing a noise-like signal, which covers a relatively broad

bandwidth. To test the MAX1213 for NPR, a “noise-like”

signal is passed through a high-order bandpass filter to

produce an approximately square spectral pedestal of

noise with about the same bandwidth as the signals

being simulated. Following the bandpass filter, the signal

is passed through a narrow band-reject filter to produce

a deep notch at the center of the noise pedestal. Finally,

this signal is applied to the MAX1213 and its digitized

results analyzed. The RMS noise power of the signal

inside the notch is compared with the RMS noise level

outside the notch using an FFT. Note that the NPR test

requires sufficiently long data records to guarantee a

suitable number of samples inside the notch. NPR for the

MAX1213 was determined for 50MHz noise bandwidth

signals, simulating a typical cable signal environment

(see the Typical Operating Characteristics for test details

and results) with a notch frequency of 28.8MHz.

Pin-Compatible Lower

Speed/Resolution Versions

Applications that require lower resolution and/or higher

speed can refer to other family members of the

MAX1213. Adjusting an application to a lower resolution

has been simplified by maintaining an identical pinout

for all members of this high-speed family. See the

Pin-Compatible Versions table for a selection of different

resolution and speed grades.

Pin Configuration

58

59

60

61

62

54

55

56

57

63

38

39

40

41

42

43

44

45

46

47

TOP VIEW

52

53

D6P

D6N

OGND

DCLKP

DCLKN

D5P

D5N

D4P

35

36

37

D4N

D3P

D3N

AGND

INN

INP

AGND

AGND

AGND

AGND

REFADJ

REFIO

AGND

48

D7N

64

65

66

67

68

23

22

21

20

19

27

26

25

24

18

29

28

32

31

30

34

33

49

50

D8N

D7P

EP

51

D8P

11

10

9

8

7

6

5

4

3

2

16

15

14

13

12

1

CLKDIV

17

MAX1213

QFN