Transfer Function

Output data coding for the MAX197 is binary in unipo-

lar mode with 1LSB = (FS / 4096) and twos-comple-

ment binary in bipolar mode with 1LSB = ((2 x

4096). Code transitions occur halfway between succes-

sive-integer LSB values. Figures 10 and 11 show the

input/output (I/O) transfer functions for unipolar and

bipolar operations, respectively. For full-scale (FS) val-

ues, refer to Table 1.

Layout, Grounding, and Bypassing

Careful printed circuit board layout is essential for best

system performance. For best performance, use a

ground plane. To reduce crosstalk and noise injection,

keep analog and digital signals separate. Digital

ground lines can run between digital signal lines to

minimize interference. Connect analog grounds and

DGND in a star configuration to AGND. For noise-free

operation, ensure the ground return from AGND to the

supply ground is low impedance and as short as possi-

ble. Connect the logic grounds directly to the supply

to AGND to minimize high- and low-frequency fluctua-

tions. If the supply is excessively noisy, connect a 5

Ω

Figure 12.

Multi-Range (±10V, ±5V, +10V, +5V),

Single +5V, 12-Bit DAS with 8+4 Bus Interface

______________________________________________________________________________________

15

_Ordering Information (continued)

28 Narrow Ceramic SB**

-55°C to +125°C

MAX197BMYI

28 Narrow Ceramic SB**

-55°C to +125°C

MAX197AMYI

28 SSOP

-40°C to +85°C

MAX197BEAI

28 SSOP

-40°C to +85°C

MAX197AEAI

28 Wide SO

-40°C to +85°C

MAX197BEWI

28 Wide SO

28 Narrow Plastic DIP

28 Narrow Plastic DIP

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

MAX197AEWI

MAX197BENI

MAX197AENI

PIN-PACKAGE

TEMP. RANGE

PART

GND

DGND

DGND

AGND

+5V

+5V

SUPPLY

R* = 5

Ω

DIGITAL

CIRCUITRY

4.7

µF

0.1

µF

MAX197

**

* OPTIONAL

** CONNECT AGND AND DGND WITH A GROUND PLANE OR A SHORT TRACE

Figure 12. Power-Supply Grounding Connection

TRANSISTOR COUNT: 2956

SUBSTRATE CONNECTED TO GND

___________________Chip Topography

CH5

CH6

CH7

INT

REFADJ

0.231"

(5.870mm)

0.144"

(3.659mm)

D2

CH0

CH1

D0

D1

AGND

CH4

CH3

CH2

REF

DGND

CLK

WR

CS

RD

HBEN

SHDN

D7

D6

D5

D4

D3

** Contact factory for availability and processing to MIL-STD-883.