AD7945ARS-BREEL データシートの表示（PDF） - Analog Devices

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AD7945ARS-BREEL

+3.3 V/+5 V Multiplying 12-Bit DACs

Analog Devices 

AD7943/AD7945/AD7948

TERMINOLOGY

Relative Accuracy

Relative Accuracy or endpoint linearity is a measure of the

maximum deviation from a straight line passing through the

endpoints of the DAC transfer function. It is measured after

adjusting for zero error and full-scale error and is normally

expressed in Least Significant Bits or as a percentage of full-

scale reading.

Differential Nonlinearity

Differential nonlinearity is the difference between the measured

change and the ideal 1 LSB change between any two adjacent

codes. A specified differential nonlinearity of 1 LSB maximum

ensures monotonicity.

Gain Error

Gain Error is a measure of the output error between an ideal

DAC and the actual device output. It is measured with all 1s

in the DAC after offset error has been adjusted out and is ex-

pressed in Least Significant Bits. Gain error is adjustable to

zero with an external potentiometer.

Output Leakage Current

Output leakage current is current which flows in the DAC lad-

der switches when these are turned off. For the IOUT1 terminal,

it can be measured by loading all 0s to the DAC and measuring

the IOUT1 current. Minimum current will flow in the IOUT2 line

when the DAC is loaded with all 1s.

Output Capacitance

This is the capacitance from the IOUT1 pin to AGND.

Output Voltage Settling Time

This is the amount of time it takes for the output to settle to a

specified level for a full-scale input change. For these devices, it

is specified both with the AD843 as the output op amp in the

normal current mode and with the AD820 in the biased current

mode.

Digital to Analog Glitch Impulse

This is the amount of charge injected into the analog output

when the inputs change state. It is specified as the area of the

glitch in nV-s. It is measured with the reference input connected

to AGND and the digital inputs toggled between all 1s and all

0s. As with Settling Time, it is specified with both the AD817

and the AD820.

AC Feedthrough Error

This is the error due to capacitive feedthrough from the DAC

reference input to the DAC IOUT1 terminal, when all 0s are

loaded in the DAC.

Digital Feedthrough

When the device is not selected, high frequency logic activity on

the device digital inputs is capacitively coupled through the

device to show up as noise on the IOUT1 pin and subsequently on

the op amp output. This noise is digital feedthrough.

DIP/SOP

PIN CONFIGURATIONS

SSOP

DIP/SOP/SSOP

DIP/SOP/SSOP

IOUT1 1

16 RFB

IOUT2 2

15 VREF

AGND

STB1

LD1

3 AD7943 14 VDD

4 TOP VIEW 13 CLR

(Not to Scale)

5

12 DGND

SRO 6

11 STB4

SRI 7

10 STB3

STB2 8

9 LD2

IOUT1 1

20 RFB

IOUT2 2

19 VREF

AGND 3 AD7943 18 VDD

STB1 4 TOP VIEW 17 CLR

(Not to Scale)

NC 5

16 NC

NC 6

LD1 7

15 NC

14 DGND

SRO 8

13 STB4

SRI 9

12 STB3

STB2 10

11 LD2

NC = NO CONNECT

IOUT1 1

20 RFB

AGND 2

19 VREF

DGND 3 AD7945 18 VDD

DB11 4 TOP VIEW 17 WR

(Not to Scale)

DB10 5

16 CS

DB9 6

15 DB0

DB8 7

14 DB1

DB7 8

13 DB2

DB6 9

12 DB3

DB5 10

11 DB4

IOUT1 1

20 RFB

AGND 2

19 VREF

DGND 3 AD7948 18 VDD

CSMSB 4 TOP VIEW 17 WR

DF/DOR

5

(Not to Scale)

16

CSLSB

CTRL 6

15 LDAC

DB7 (MSB) 7

14 DB0 (LSB)

DB6 8

13 DB1

DB5 9

12 DB2

DB4 10

11 DB3

–8–

REV. B

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