Burr Brown Corporation ADS7821UB-1K, ADS7821UB, ADS7821U-1K, ADS7821U, ADS7821PB Datasheet

1

®

ADS7821

FEATURES

● 100kHz min SAMPLING RATE

● 0 to +5V INPUT RANGE

● 86dB min SINAD WITH 20kHz INPUT

● DNL: 16-bits “No Missing Codes”

● SINGLE +5V SUPPLY OPERATION

● PIN-COMPATIBLE WITH 12-BIT ADS7820

● USES INTERNAL OR EXTERNAL

REFERENCE

● FULL PARALLEL DATA OUTPUT

● 100mW max POWER DISSIPATION

● 28-PIN 0.3" PLASTIC DIP AND SOIC

ADS7821

DESCRIPTION

The ADS7821 is a complete 16-bit sampling A/D
using state-of-the-art CMOS structures. It contains a
complete 16-bit, capacitor-based, SAR A/D with S/H,
reference, clock, interface for microprocessor use, and
three-state output drivers.

The ADS7821 is specified at a 100kHz sampling rate,
and guaranteed over the full temperature range. Laser­trimmed scaling resistors provide a 0 to +5V input
range, with power dissipation under 100mW.

The 28-pin ADS7821 is available in a plastic 0.3" DIP
and in an SOIC, both fully specified for operation over
the –25°C to +85°C range.

16-Bit 10µs Sampling CMOS

ANALOG-to-DIGITAL CONVERTER

®

Successive Approximation Register and Control Logic

Clock

Output

Latches

and

Three

State

Drivers

Three

State

Parallel

Data

Bus

BUSY

Comparator

BYTE

CS

R/C

CDAC

Internal

+2.5V Ref

Buffer

4kΩ

0 to +5V Input

REF

CAP

5kΩ

20kΩ6.66kΩ

©

1996 Burr-Brown Corporation PDS-1323A Printed in U.S.A. June, 1996

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: [phone] • Twx: 910-952-1111

Internet: http://www.burr-brown.com/ • FAXLine: [phone] (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: [phone] • Immediate Product Info: [phone]

ADS7821

ADS7821

®

2ADS7821

SPECIFICATIONS

ELECTRICAL

TA = –25°C to +85°C, fS = 100kHz, V

DIG

= V

ANA

= VD = +5V, using external reference, unless otherwise specified.

ADS7821P, U ADS7821PB, UB

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN
assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject
to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not
authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.

Parallel 16 bits
Straight Binary

RESOLUTION 16 ✱ Bits
ANALOG INPUT

Voltage Range 0 to +5 ✱ V
Impedance 10 ✱ kΩ
Capacitance 35 ✱ pF

THROUGHPUT SPEED

Conversion Cycle Acquire and Convert 10 ✱ µs
Throughput Rate 100 ✱ kHz

DC ACCURACY

Integral Linearity Error ±4 ±3 LSB

(1)

No Missing Codes 15 16 Bits
Transition Noise

(2)

0.9 ✱ LSB

Full Scale Error

(3,4)

±0.5 ±0.25 %
Full Scale Error Drift ±2 ✱ ppm/ °C
Full Scale Error

(3,4)

Internal Reference ±0.5 ±0.25 %
Full Scale Error Drift Internal Reference ±7 ±5 ppm/°C
Offset Error ±8 ±4mV
Offset Error Drift ±2 ✱ ppm/ °C
Power Supply Sensitivity +4.75V < V

D

< +5.25V ±12 ±8 LSB

(V

DIG

= V

ANA

= VD)

AC ACCURACY

Spurious-Free Dynamic Range f

IN

= 20kHz 90 94 dB

(5)

Total Harmonic Distortion f

IN

= 20kHz –90 –94 dB

Signal-to-(Noise+Distortion) f

IN

= 20kHz 83 86 dB

f

IN

= –60dB Input 28 30 dB

Signal-to-Noise f

IN

= 20kHz 83 86 dB

Full-Power Bandwidth

(6)

250 ✱ kHz

SAMPLING DYNAMICS

Aperture Delay 40 ✱ ns
Transient Response FS Step 2 ✱ µs
Overvoltage Recovery

(7)

150 ✱ ns

REFERENCE

Internal Reference Voltage 2.48 2.5 2.52 ✱✱✱ V
Internal Reference Source Current 1 ✱ µA

(Must use external buffer)

Internal Reference Drift 8 ✱ ppm/ °C
External Reference Voltage Range 2.3 2.5 2.7 ✱✱✱ V

for Specified Linearity

External Reference Current Drain Ext. 2.5000V Ref 100 ✱ µA

DIGITAL INPUTS

Logic Levels

V

IL

–0.3 +0.8 ✱✱V

V

IH

+2.0 VD +0.3V ✱✱V

I

IL

±10 ✱ µA

I

IH

±10 ✱ µA

DIGITAL OUTPUTS

Data Format
Data Coding

V

OL

I

SINK

= 1.6mA +0.4 ✱ V

V

OH

I

SOURCE

= 500µA+4 ✱ V

Leakage Current High-Z State, ±5 ✱ µA

V

OUT

= 0V to V

DIG

Output Capacitance High-Z State 15 ✱ pF

DIGITAL TIMING

Bus Access Time 83 ✱ ns
Bus Relinquish Time 83 ✱ ns

3

®

ADS7821

POWER SUPPLIES

Specified Performance

V

DIG

Must be ≤ V

ANA

+4.75 +5 +5.25 ✱✱✱ V

V

ANA

+4.75 +5 +5.25 ✱✱✱ V

I

DIG

0.3 ✱ mA

I

ANA

16 ✱ mA

Power Dissipation f

S

= 100kHz 100 ✱ mW

TEMPERATURE RANGE

Specified Performance –25 +85 ✱✱ °C
Derated Performance –55 +125 ✱✱ °C
Storage –65 +150 ✱✱°C
Thermal Resistance (

θ

JA

)
Plastic DIP 75 ✱ °C/W
SOIC 75 ✱ °C/W

NOTES: (1) LSB means Least Significant Bit. For the 16-bit, 0 to +5V input ADS721, one LSB is 76µV. (2) Typical rms noise at worst case transitions and
temperatures. (3) Adjustable to zero with external potentiometer as shown in Figure 6a. (4) Full scale error is the worst case of Full Scale untrimmed deviation from
ideal last code transition divided by the transition voltage and includes the effect of offset error. (5) All specifications in dB are referred to a full-scale input. (6) Full­Power Bandwidth defined as Full-Scale input frequency at which Signal-to-(Noise + Distortion) degrades to 60dB, or 10 bits of accuracy. (7) Recovers to specified
performance after 2 x FS input overvoltage.

SPECIFICATIONS (CONT)

ELECTRICAL

TA = –25°C to +85°C, fS = 100kHz, V

DIG

= V

ANA

= VD = +5V, using external reference, unless otherwise specified.

ADS7821P, U ADS7821PB, UB

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

ABSOLUTE MAXIMUM RATINGS

Analog Inputs: VIN......................................................–0.7V to V

ANA

+0.3V

REF ................................... AGND2 –0.3V to +V

ANA

+0.3V

CAP .......................................... Indefinite Short to AGND2,

Momentary Short to V

ANA

Ground Voltage Differences: DGND, AGND1, AGND2 ................... ±0.3V

V

ANA

.......................................................................................................7V

V

DIG

to V

ANA

.....................................................................................+0.3V

V

DIG

.......................................................................................................7V

Digital Inputs ............................................................ –0.3V to +V

DIG

+0.3V

Maximum Junction Temperature ................................................... +165°C

Internal Power Dissipation ............................................................. 825mW

Lead Temperature (soldering, 10s)................................................ +300°C

PACKAGE INFORMATION

PACKAGE DRAWING

PRODUCT PACKAGE NUMBER

(1)

ADS7821P Plastic DIP 246
ADS7821PB Plastic DIP 246
ADS7821U SOIC 217
ADS7821UB SOIC 217

NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.

MINIMUM

SIGNAL-TO-

MAXIMUM (NOISE + SPECIFICATION

LINEARITY DISTORTION) TEMPERATURE

PRODUCT ERROR (LSB) RATIO (dB) RANGE PACKAGE

ADS7821P ±4 83 –25°C to +85°C Plastic DIP
ADS7821PB ±3 86 –25°C to +85°C Plastic DIP
ADS7821U ±4 83 –25° C to +85°C SOIC
ADS7821UB ±3 86 –25°C to +85°C SOIC

ORDERING INFORMATION

ELECTROSTATIC
DISCHARGE SENSITIVITY

Electrostatic discharge can cause damage ranging from per­formance degradation to complete device failure. Burr­Brown Corporation recommends that all integrated circuits
be handled and stored using appropriate ESD protection
methods.

ESD damage can range from subtle performance degrada­tion to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet
published specifications.