ZN426E8DP14.pdf 데이터시트 (총 5 페이지) - 파일 다운로드 ZN426E8DP14 데이타시트 다운로드

No Preview Available !

THIS DOCUMENT IS FOR MAINTENANCE
PURPOSES ONLY AND IS NOT
RECOMMENDED FOR NEW DESIGNS

No Preview Available !

ZN426E8
8-BIT D-A CONVERTER
MAY 1994
DS3021-2.2
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.
FEATURES
s ±1/2 LSB Linearity Error
s Guaranteed Monolithic over the Full Operating
Temperature Range
s 0°C to +70°C
s TTL and 5V CMOS Compatible
s Single 5V Supply
s Settling Time 1 microsecond Typical
s Only Reference Capacitor and Resistor Required
ABSOLUTE MAXIMUM RATINGS
Supply voltage +7.0V
Max.voltage, logic and VREF inputs+5.5V
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
BIT 3
BIT 2
(MSB) BIT 1
ANALOG OUTPUT
VREF IN
VREF OUT
0V
1 14
2 13
3 12
4 ZN426E8 11
5 10
69
78
VCC (+5V)
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8 (LSB)
NC
DP14
Fig.1 Pin connections (not to scale) - top view
Fig.2 System diagram

No Preview Available !

ZN426
ELECTRICAL CHARACTERISTICS
(at Tamb = 25°C and VCC = +5V unless otherwise specified)
Parameter
Symbol
Min.
Typ.
Max.
Units
Conditions
Converter
Resolution
8 - - bits
Non-linearity
- - ±0.5 LSB
Differential non-linearity
- ±0.5 -
LSB Note 1
Settling time to 0.5LSB
- 1.0 -
µs 1LSB step
Settling time to 0.5LSB
- 2.0 -
µs All bits ON to OFF
or OFF to ON
Offset voltage ZN426E8 and D
VOS temperature coefficient
Full-scale output
Full-scale temp. coefficient
Non-linearity temp. coefficient
VOS
-
-
2.545
-
-
3.0
5
2.550
3
7.5
5.0
-
2.555
-
-
mV
µV/°C
V
ppm/°C
ppm/°C
All bits OFF
All bits ON
Ext. VREF = 2.560V
Ext. VREF = 2.560V
Relative to F.S.R.
Analog output resistance
External reference voltage
RO -
0
10 -
- 3.0
k
V
Supply voltage
VCC 4.5 - 5.5
V
Supply current
IS - 5 9 mA
High level input voltage
VIH 2.0
-
-
V
Low level input voltage
VIL -
- 0.7
V
High level input current
IIH -
- 10 µA VCC = max.
VI = 2.4V
- - 100 µA VCC = max.
VI = 5.5V
Low level input current
IIL -
- -0.18 mA VCC = max.
VI = 0.3V
Internal voltage reference
Output voltage
VREF
2.475
2.55
2.626
V Note 2 RREF = 390
Slope resistance
RS - 1 2
RREF = 390
VREF temperature coefficient
-
40
-
ppm/°C
RREF = 390
NOTE 1: Monotonic over full temperature range.
NOTE 2:The internal reference requires a 1µF stabilising capacitor between VREF OUT and 0V and a 390resistor, RREF,
between VCC and VREF OUT.
INTRODUCTION
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.
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
supply power to the internal reference so RREF and CREF
can be omitted.
2

No Preview Available !

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 VREF by
transistor switches specially designed for low offset voltage
(typically 1mV).
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.
APPLICATIONS
Fig.3 The R-2R ladder network
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
temperature coefficient of the analog output resistance RO,
will be less than 0.004% per °C (or 1LSB/100°C) if RL is
chosen to be 650k.
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 6k. The calibration
procedure is as follows:
i. Set all bits to OFF (low) and adjust R2 until
VOUT = 0.000V.
ii. Set all bits to ON (high) and adjust R1 until
VOUT = Normal full-scale reading - 1LSB
iii. Repeat i. and ii.
e.g. Set F.S.R. to + 3.840V - 1LSB
=3.825V
(1LSB
=
3.84
256
=15.0mV)
Fig.4 8-bit D-A converter
3

No Preview Available !

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,
Wiltshire, United Kingdom. SN2 2QW
Tel: (01793) 518000
Fax: (01793) 518411
GEC PLESSEY SEMICONDUCTORS
P.O. Box 660017,
1500 Green Hills Road,
Scotts Valley, California 95067-0017,
United States of America.
Tel (408) 438 2900
Fax: (408) 438 5576
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
• JAPAN Tokyo Tel: (03) 5276-5501 Fax: (03) 5276-5510
• 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
Swindon Tel: (01793) 518510 Fax: (01793) 518582
These are supported by Agents and Distributors in major countries world-wide.
© GEC Plessey Semiconductors 1994 Publication No. DS3021 Issue No. 2.2 May 1994
TECHNICAL DOCUMENTATION - NOT FOR RESALE. PRINTED IN UNITED KINGDOM
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
4information 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