ZN426E8DP14 [ZARLINK]

8-BIT D-A CONVERTER; 8位D -A转换器


型号：	ZN426E8DP14
厂家：	ZARLINK SEMICONDUCTOR INC
描述：	8-BIT D-A CONVERTER 8位D -A转换器转换器
文件：	总5页 (文件大小：140K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

THIS DOCUMENT IS FOR MAINTENANCE

PURPOSES ONLY AND IS NOT

RECOMMENDED FOR NEW DESIGNS

MAY 1994

DS3021-2.2

ZN426E8

8-BIT D-A CONVERTER

The ZN426 is

a monolithic 8-bit D-A converter

containing an R-2R ladder network of diffused resistors with

precision bipolar switches, and a 2.5V precision voltage

reference.

V_CC(+5V)

BIT 4

BIT 5

BIT 3

BIT 2

(MSB) BIT 1

FEATURES

ANALOG OUTPUT

V_REFIN

BIT 6

BIT 7

BIT 8 (LSB)

ZN426E8

■ ± / LSB Linearity Error

■ Guaranteed Monolithic over the Full Operating

Temperature Range

■ 0°C to +70°C

V_REFOUT

■ TTL and 5V CMOS Compatible

■ Single 5V Supply

■ Settling Time 1 microsecond Typical

■ Only Reference Capacitor and Resistor Required

DP14

ABSOLUTE MAXIMUM RATINGS

Supply voltage +7.0V

Fig.1 Pin connections (not to scale) - top view

Max.voltage, logic and V

inputs+5.5V

REF

Operating temperature range0°C to +70°C

Storage temperature range-55°C to +125°C

ORDERING INFORMATION

Ambient operating temperature 0°C to +70°C

Package, ZN426E8DP14

Fig.2 System diagram

ZN426

ELECTRICAL CHARACTERISTICS

(at T

= 25°C and V = +5V unless otherwise speciﬁed)

amb

Parameter

Symbol

Units

Conditions

Min.

Typ.

Max.

Converter

Resolution

bits

LSB

µs

Non-linearity

±0.5

Differential non-linearity

Settling time to 0.5LSB

±0.5

1.0

2.0

Note 1

1LSB step

µs

All bits ON to OFF

or OFF to ON

Offset voltage ZN426E8 and D

3.0

5.0

µV/°C

All bits OFF

temperature coefﬁcient

Full-scale output

2.545

2.550

2.555

All bits ON

Ext. V

= 2.560V

REF

Full-scale temp. coefﬁcient

Non-linearity temp. coefﬁcient

Analog output resistance

External reference voltage

Supply voltage

7.5

ppm/°C

REF

ppm/°C

Relative to F.S.R.

kΩ

3.0

5.5

4.5

Supply current

High level input voltage

Low level input voltage

High level input current

2.0

0.7

µA

= max.

V = 2.4V

100

µA

= max.

V = 5.5V

Low level input current

-0.18

= max.

V = 0.3V

Internal voltage reference

Output voltage

2.475

2.55

2.626

Ω

Note 2 R

= 390Ω

REF

Slope resistance

= 390Ω

REF

temperature coefﬁcient

ppm/°C

REF

NOTE 1: Monotonic over full temperature range.

NOTE 2:The internal reference requires a 1µF stabilising capacitor between V

and 0V and a 390Ω resistor, R

REF OUT

REF

between V and V

REF OUT

INTRODUCTION

The use of on-chip voltage reference is pin optional to

retain ﬂexibility. An external ﬁxed or varying reference may

therefore be substituted. In this case there is no need to

The ZN426 is an 8-bit D-A converter. It contains an

advanced design of R-2R ladder network and an array of

precision bipolar switches plus a 2.5V precision voltage

reference on a single monolithic chip.

The special design of the ladder network results in full

8-bit accuracy using normal defused resistors.

supply power to the internal reference so R

can be omitted.

and C

REF

ZN426

Binary weighted voltages are produced at the output of

the R-2R ladder, the value depending on the digital number

applied to the bit inputs.

The converter is of the voltage switching type and uses

an R-2R resistor ladder network as shown in Fig.3.

Each 2R element is connected either to 0V or V

REF

transistor switches specially designed for low offset voltage

(typically 1mV).

Fig.3 The R-2R ladder network

APPLICATIONS

8-bit D-A Converter

The ZN426 gives an analog voltage output directly from

pin 4 therefore the usual current to voltage converting

ampliﬁer is not required. The output voltage drift, due to the

i. Set all bits to OFF (low) and adjust R until

= 0.000V.

OUT

temperature coefﬁcient of the analog output resistance R ,

ii. Set all bits to ON (high) and adjust R until

will be less than 0.004% per °C (or 1LSB/100°C) if R is

chosen to be ≥ 650kΩ.

= Normal full-scale reading - 1LSB

OUT

iii. Repeat i. and ii.

e.g. Set F.S.R. to + 3.840V - 1LSB

In order to remove the offset voltage and to calibrate the

converter a buffer ampliﬁer is necessary. Fig.4 shows a

typical scheme using the internal reference voltage. To

minimise temperature drift in this and similar applications the

source resistance to the inverting input of the operational

ampliﬁer should be approximately 6kΩ. The calibration

procedure is as follows:

=3.825V

3.84

256

(1LSB =

=15.0mV)

Fig.4 8-bit D-A converter

ZN426

Alternative Output Buffer Using the 741

The circuit of Fig.5, employing the 741 operational

ampliﬁer, may be used as the output buffer.

Fig.5 The ZLD741 as output buffer

HEADQUARTERS OPERATIONS

GEC PLESSEY SEMICONDUCTORS

Cheney Manor, Swindon,

CUSTOMER SERVICE CENTRES

• FRANCE & BENELUX Les Ulis Cedex Tel: (1) 64 46 23 45 Fax: (1) 64 46 06 07

• GERMANY Munich Tel: (089) 3609 06-0 Fax: (089) 3609 06-55

• ITALY Milan Tel: (02) 66040867 Fax: (02)66040993

Wiltshire, United Kingdom. SN2 2QW

Tel: (01793) 518000

• JAPAN Tokyo Tel: (03) 5276-5501 Fax: (03) 5276-5510

Fax: (01793) 518411

• NORTH AMERICA Scotts Valley, USA Tel: (408) 438 2900 Fax: (408) 438 7023

• SOUTH EAST ASIA Singapore Tel: (65) 3827708 Fax: (65) 3828872

• SWEDEN Stockholm Tel: 46 8 702 97 70 Fax: 46 8 640 47 36

• TAIWAN, ROC Taipei Tel: 886 2 5461260 Fax: 886 2 7190260

• UK, EIRE, DENMARK, FINLAND & NORWAY

GEC PLESSEY SEMICONDUCTORS

P.O. Box 660017,

1500 Green Hills Road,

Scotts Valley, California 95067-0017,

United States of America.

Tel (408) 438 2900

Swindon Tel: (01793) 518510 Fax: (01793) 518582

These are supported by Agents and Distributors in major countries world-wide.

TECHNICAL DOCUMENTATION - NOT FOR RESALE. PRINTED IN UNITED KINGDOM

Fax: (408) 438 5576

This publication is issued to provide information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose nor form part of any order or contract nor to be

regarded as a representation relating to the products or services concerned. No warranty or guarantee express or implied is made regarding the capability, performance or suitability of any product or service. The

Company reserves the right to alter without prior knowledge the speciﬁcation, design or price of any product or service. Information concerning possible methods of use is provided as a guide only and does not

constitute any guarantee that such methods of use will be satisfactory in a speciﬁc piece of equipment. It is the user's responsibility to fully determine the performance and suitability of any equipment using such

information and to ensure that any publication or data used is up to date and has not been superseded. These products are not suitable for use in any medical products whose failure to perform may result in

signiﬁcant injury or death to the user

All products and materials are sold and services provided subject to the Company's conditions of sale

which are available on request

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