ADC0831.PDF

January 1995

ADC0831/ADC0832/ADC0834 and ADC0838

8-Bit Serial I/O A/D Converters with Multiplexer Options

General Description

The ADC0831 series are 8-bit successive approximation

A/D converters with a serial I/O and configurable input mul-

tiplexers with up to 8 channels. The serial I/O is configured

to comply with the NSC MICROWIRE TM serial data ex-

change standard for easy interface to the COPS TM family of

processors, and can interface with standard shift registers

or m Ps.

The 2-, 4- or 8-channel multiplexers are software configured

for single-ended or differential inputs as well as channel as-

signment.

The differential analog voltage input allows increasing the

common-mode rejection and offsetting the analog zero in-

put voltage value. In addition, the voltage reference input

can be adjusted to allow encoding any smaller analog volt-

age span to the full 8 bits of resolution.

Y Operates ratiometrically or with 5 V DC voltage

reference

Y No zero or full-scale adjust required

Y 2-, 4- or 8-channel multiplexer options with address

logic

Y Shunt regulator allows operation with high voltage

supplies

Y 0V to 5V input range with single 5V power supply

Y Remote operation with serial digital data link

Y TTL/MOS input/output compatible

Y 0.3 × standard width, 8-, 14- or 20-pin DIP package

Y 20 Pin Molded Chip Carrier Package (ADC0838 only)

Y Surface-Mount Package

Key Specifications

Y Resolution

Features

Y NSC MICROWIRE compatibleÐdirect interface to

COPS family processors

Y Easy interface to all microprocessors, or operates

``stand-alone''

8 Bits

Y Total Unadjusted Error

g (/2

LSB and g 1 LSB

Y Single Supply

5 V DC

Y Low Power

15 mW

Y Conversion Time

32 m s

Typical Application

TL/H/5583±1

TRI-STATE É is a registered trademark of National Semiconductor Corporation.

COPS TM and MICROWIRE TM are trademarks of National Semiconductor Corporation.

C 1995 National Semiconductor Corporation

TL/H/5583

RRD-B30M115/Printed in U. S. A.

Absolute Maximum Ratings (Notes1&2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

Current into V a (Note 3)

Lead Temperature (Soldering 10 sec.)

Dual-In-Line Package (Plastic)

260 § C

Dual-In-Line Package (Ceramic)

300 § C

15 mA

Molded Chip Carrier Package

Vapor Phase (60 sec.)

215 § C

Supply Voltage, V CC (Note 3)

6.5V

Infrared (15 sec.)

220 § C

Voltage

Logic Inputs

b 0.3V to V CC a 0.3V

ESD Susceptibility (Note 5)

2000V

Analog Inputs

b 0.3V to V CC a 0.3V

Operating Ratings (Notes1&2)

Supply Voltage, V CC

Input Current per Pin (Note 4)

g 5mA

Package

g 20 mA

4.5 V DC to 6.3 V DC

Storage Temperature

b 65 § Cto a 150 § C

Temperature Range

T MIN s T A s T MAX

ADC0831/8BCJ,

ADC0831/4/8CCJ,

ADC0832BIWM,

ADC0831/2/4/8CIWM

Package Dissipation

at T A e 25 § C (Board Mount)

0.8W

b 40 § Cto a 85 § C

ADC0831/2//4/8BCN,

ADC0838BCV,

ADC0831/2/4/8CCN,

ADC0838CCV,

ADC0831/2/4/8CCWM

0 § Cto a 70 § C

Converter and Multiplexer Electrical Characteristics

The following specifications apply for V CC e V ae V REF e 5V, V REF s V CC a 0.1V, T A e T j e 25 § C, and f CLK e 250 kHz

unless otherwise specified. Boldface limits apply from T MIN to T MAX .

BCJ, BIWM,

BCV, CCV, CCWM, BCN

CIWM and CCJ Devices

and CCN Devices

Parameter

Conditions

Tested Design

Units

Typ

Limit

(Note 12)

(Note 13) (Note 14)

(Note 13)

(Note 14)

CONVERTER AND MULTIPLEXER CHARACTERISTICS

Total Unadjusted Error

V REF e 5.00 V

ADC0838BCV

(Note 6)

g (/2

ADC0831/2/4/8BCN

g (/2

LSB

ADC0831/8BCJ

g (/2

ADC0832BIWM

g (/2

ADC0838CCV

g 1

ADC0831/2/4/8CCN

g 1

ADC0831/2/4/8CCWM

g 1

ADC0831/4/8CCJ

g 1

ADC0831/2/4/8CIWM

g 1

Minimum Reference

3.5

1.3

3.5

1.3

1.3 k X

Input Resistance (Note 7)

Maximum Reference

3.5

5.9

3.5

5.4

5.9 k X

Input Resistance (Note 7)

Maximum Common-Mode Input

V CC a 0.05

V CC a 0.05 V CC a 0.05 V

Range (Note 8)

Minimum Common-Mode Input

GND b 0.05

GND b 0.05 GND b 0.05 V

Range (Note 8)

DC Common-Mode Error

g (/16

g (/4

g (/16

g (/4

LSB

Converter and Multiplexer Electrical Characteristics (Continued)

The following specifications apply for V CC e V ae 5V, T A e T j e 25 § C, and f CLK e 250 kHz unless otherwise specified.

Boldface limits apply from T MIN to T MAX .

BCJ, BIWM,

BCV, CCV, CCWM, BCN

CIWM and CCJ Devices

and CCN Devices

Parameter

Conditions

Tested Design

Units

Typ

Limit

(Note 12)

(Note 13) (Note 14)

CONVERTER AND MULTIPLEXER CHARACTERISTICS (Continued)

Change in zero

15 mA into V a

error from V CC e 5V

V CC e N.C.

to internal zener

V REF e 5V

operation (Note 3)

1 LSB

V Z , internal

MIN 15 mA into V a

6.3

diode breakdown MAX

8.5

8.5 V

(at V a ) (Note 3)

Power Supply Sensitivity

V CC e 5V g 5% g (/16

g (/4

g (/16

g (/4

LSB

I OFF , Off Channel Leakage On Channel e 5V,

b 0.2

b 0.2 b 1 m A

Current (Note 9)

Off Channel e 0V

b 1

On Channel e 0V,

a 0.2

a 0.2 a 1 m A

Off Channel e 5V

a 1

I ON , On Channel Leakage On Channel e 0V,

b 0.2

b 0.2 b 1 m A

Current (Note 9)

Off Channel e 5V

b 1

On Channel e 5V,

a 0.2

a 0.2 a 1 m A

Off Channel e 0V

a 1

DIGITAL AND DC CHARACTERISTICS

V IN(1) , Logical ``1'' Input

V CC e 5.25V

2.0

2.0 V

Voltage (Min)

V IN(0) , Logical ``0'' Input

V CC e 4.75V

0.8

0.8 V

Voltage (Max)

I IN(1) , Logical ``1'' Input

V IN e 5.0V

0.005

1 m A

Current (Max)

I IN(0) , Logical ``0'' Input

V IN e 0V

b 0.005 b 1

b 0.005 b 1 b 1 m A

Current (Max)

V OUT(1) , Logical ``1'' Output V CC e 4.75V

Voltage (Min)

I OUT eb 360 m A

2.4

2.4 V

I OUT eb 10 m A

4.5

4.5 V

V OUT(0) , Logical ``0'' Output V CC e 4.75V

0.4

0.4 V

Voltage (Max)

I OUT e 1.6 mA

I OUT , TRI-STATE Output

V OUT e 0V

b 0.1 b 3

b 0.1 b 3 b 3 m A

Current (Max)

V OUT e 5V

0.1

0.1 a 3 a 3 m A

I SOURCE , Output Source

V OUT e 0V

b 14 b 6.5

b 14 b 7.5 b 6.5 mA

Current (Min)

I SINK , Output Sink Current (Min) V OUT e V CC

8.0

9.0

8.0 mA

I CC , Supply Current (Max)

ADC0831, ADC0834,

0.9

2.5

0.9

2.5

2.5 mA

ADC0838

ADC0832

Includes Ladder

2.3

6.5

2.3

6.5

6.5 mA

Current

AC Characteristics

The following specifications apply for V CC e 5V, t r e t f e 20 ns and 25 § C unless otherwise specified.

Typ

Tested Design

Limit

Parameter

Conditions

Limit

(Note 12)

Units

(Note 13)

(Note 14)

f CLK , Clock Frequency

Min

kHz

Max

400

kHz

t C , Conversion Time

Not including MUX Addressing Time

1/f CLK

Clock Duty Cycle

Min

40 %

(Note 10)

Max

60 %

t SET-UP ,CSFalling Edge or

250

Data Input Valid to CLK

Rising Edge

t HOLD , Data Input Valid

after CLK Rising Edge

t pd1 ,t pd0 ÐCLK Falling

C L e 100 pF

Edge to Output Data Valid

Data MSB First

650

1500

(Note 11)

Data LSB First

250

600

t 1H ,t 0H ,ÐRising Edge of

C L e 10 pF, R L e 10k

125

250

CS to Data Output and

(see TRI-STATE É Test Circuits)

SARS Hi ±Z

C L e 100 pf, R L e 2k

500

C IN , Capacitance of Logic

Input

C OUT , Capacitance of Logic

Outputs

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating

the device beyond its specified operating conditions.

Note 2: All voltages are measured with respect to the ground plugs.

Note 3: Internal zener diodes (6.3 to 8.5V) are connected from V a to GND and V CC to GND. The zener at V a can operate as a shunt regulator and is connected

to V CC via a conventional diode. Since the zener voltage equals the A/D's breakdown voltage, the diode insures that V CC will be below breakdown when the device

is powered from V a . Functionality is therefore guaranteed for V a operation even though the resultant voltage at V CC may exceed the specified Absolute Max of

6.5V. It is recommended that a resistor be used to limit the max current into V a . (See Figure3 in Functional Description Section 6.0)

Note 4: When the input voltage (V IN ) at any pin exceeds the power supply rails (V IN k V b or V IN l V a ) the absolute value of current at that pin should be limited

to 5 mA or less. The 20 mA package input current limits the number of pins that can exceed the power supply boundaries witha5mAcurrent limit to four.

Note 5: Human body model, 100 pF discharged through a 1.5 k X resistor.

Note 6: Total unadjusted error includes offset, full-scale, linearity, and multiplexer errors.

Note 7: Cannot be tested for ADC0832.

Note 8: For V IN ( b ) t V IN ( a ) the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input (see Block Diagram) which will forward

conduct for analog input voltages one diode drop below ground or one diode drop greater then the V CC supply. Be careful, during testing at low V CC levels (4.5V),

as high level analog inputs (5V) can cause this input diode to conductÐespecially at elevated temperatures, and cause errors for analog inputs near full-scale. The

spec allows 50 mV forward bias of either diode. This means that as long as the analog V IN or V REF does not exceed the supply voltage by more than 50 mV, the

output code will be correct. To achieve an absolute 0 V DC to5V DC input voltage range will therefore require a minimum supply voltage of 4.950 V DC over

temperature variations, initial tolerance and loading.

Note 9: Leakage current is measured with the clock not switching.

Note 10: A 40% to 60% clock duty cycle range insures proper operation at all clock frequencies. In the case that an available clock has a duty cycle outside of

these limits, the minimum, time the clock is high or the minimum time the clock is low must be at least 1 m s. The maximum time the clock can be high is 60 m s. The

clock can be stopped when low so long as the analog input voltage remains stable.

Note 11: Since data, MSB first, is the output of the comparator used in the successive approximation loop, an additional delay is built in (see Block Diagram) to

allow for comparator response time.

Note 12: Typicals are at 25 § C and represent most likely parametric norm.

Note 13: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).

Note 14: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing quality levels.

Typical Performance Characteristics

Unadjusted Offset Error

Linearity Error vs V REF

Linearity Error vs

vs V REF Voltage

Voltage

Temperature

TL/H/5583±2

Power Supply Current vs

Temperature (ADC0838,

Output Current vs

Linearity Error vs f CLK

ADC0831, ADC0834)

Temperature

Note: For ADC0832 add I REF .

TL/H/5583±40

Power Supply Current

vs f CLK

Leakage Current Test Circuit

TL/H/5583±29

TL/H/5583±3

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