Analog Input

The analog input to the A/D converter is supplied

through the BNC coaxial connector labeled AIN.

Analog input polarity is controlled by the first

position switch on the DIP-switch, SW-1. If it is

on, the input is unipolar ranging from GND to

VREF. If the switch is off, the input range is bi-

polar with the magnitude of the reference voltage

defining both zero- and full-scale (

±VREF).

The A/D converter’s internal analog input buffer

requires a source impedance of less than 400

Ω

at 1MHz for stability. Acquisition and throughput

are specified assuming a dc source impedance of

less than 200

Ω. Infinitely large dc source imped-

ances can be accommodated by adding capaci-

tance (typically 1000pF) from the analog input to

ground. However, high dc source resistances de-

grade acquisition time and consequently through-

put.

CS

EOC

D1

D2

D3

D4

D5

D6

D7

D8

D9

D10

D11

D12

D13

D14

D15

A0

2

3

4

5

6

7

8

9

12

13

14

15

16

17

18

19

38

21

22

23

VD-

VD+

+

36

11

10

C1

C2

C3

C4

VA-

VA+

25

27

30

C5

C6

C10

C11

+

SCLK

SDATA

AIN

CLKIN

39

40

26

20

32

VREF

28

RESET

31 TST

29 REFBUF

R10

C7

R8

R9

SW2

VD+

U1

Reset

VD+

R23 (optional)

VA-

D0

C12

SW1-4

+

+

37 EOT

HOLD

1

R3

+5V

-5V

VD+

VD-

R1

R2

VA+

VA-

RD

R7

R5

VD+

R4

24

34

35

BP/UP

CAL

INTLV

SW1-1

SW1-2

SW1-3

33 BW

R12

R13

R11

R6

CS5012A

CS5014

CS5016

CS5012

Figure 1. CDB5012, CDB5012A, CDB5014, CDB5016 Schematic

(Reference Circuitry Appears in Figure 3)

CDB5012, CDB5012A, CDB5014, CDB5016

DS14DB11

2