AD7835APZ-REEL1 View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD7835APZ-REEL1

LC2MOS Quad 14-Bit DACs

Analog Devices 

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. It is normally

expressed in LSBs 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.

DC Crosstalk

Although the common input reference (IR) voltage signals are

internally buffered, small IR drops in individual DAC reference

inputs across the die mean that an update to one channel

produces a dc output change in one or more channel outputs.

The four DAC outputs are buffered by op amps sharing

common VDD and VSS power supplies. If the dc load current

changes in one channel due to an update, a further dc change

occurs in one or more of the channel outputs. This effect is

most obvious at high load currents and is reduced as the load

currents are reduced. With high impedance loads, the effect is

virtually unmeasurable.

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.

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-secs. It is measured with the reference inputs

connected to 0 V and the digital inputs toggled between all

1s and all 0s.

Channel-to-Channel Isolation

Channel-to-channel isolation refers to the proportion of input

signal from the reference input of one DAC that appears at the

output of the other DAC. It is expressed in decibels (dB). The

AD7834 has no specification for channel-to-channel isolation

because it has one reference for all DACs. Channel-to-channel

isolation is specified for the AD7835.

AD7834/AD7835

DAC-to-DAC Crosstalk

DAC-to-DAC crosstalk is defined as the glitch impulse that

appears at the output of one converter due to both the digital

change and the subsequent analog output (O/P) change at

another converter. It is specified in nV-secs.

Digital Crosstalk

The glitch impulse transferred to the output of one converter

due to a change in digital input code to the other converter is

defined as the digital crosstalk and is specified in nV-secs.

Digital Feedthrough

When the device is not selected, high frequency logic activity

on its digital inputs can be capacitively coupled both across and

through the device to show up as noise on the VOUT pins. This

noise is digital feedthrough.

DC Output Impedance

DC output impedance is the effective output source resistance.

It is dominated by package lead resistance.

Full-Scale Error

Full-scale error is the error in DAC output voltage when all 1s

are loaded into the DAC latch. Ideally, the output voltage, with

all 1s loaded into the DAC latch, should be VREF(+) – 1 LSB.

Full-scale error does not include zero-scale error.

Zero-Scale Error

Zero-scale error is the error in the DAC output voltage when

all 0s are loaded into the DAC latch. Ideally, the output voltage,

with all 0s in the DAC latch, is equal to VREF(−). Zero-scale

error is due mainly to offsets in the output amplifier.

Gain Error

Gain error is defined as (full-scale error) − (zero-scale error).

Rev. D | Page 13 of 28

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