Low Power, Low Cost
2.5 V Reference
AD680
FEATURES
Low quiescent current at 250 μA max
Laser trimmed to high accuracy
2.5 V ± 5 mV max (AN, AR grades)
Trimmed temperature coefficient
20 ppm/°C max (AN, AR grades)
Low noise at 8 μV p-p from 0.1 Hz to 10 Hz
250 nV/√Hz wideband
Temperature output pin (N, R packages)
Available in three package styles
8-lead PDIP, 8-lead SOIC, and 3-pin TO-92
CONNECTION DIAGRAMS
TP*
1
+V
IN 2
TEMP
3
GND
4
8
TP*
TP*
AD680
7
6
V
OUT
TOP VIEW
(Not to Scale)
5
NC
NC = NO CONNECT
* TP DENOTES FACTORY TEST POINT.
NO CONNECTIONS SHOULD BE MADE
TO THESE PINS.
00813-003
Figure 1. 8-Lead PDIP and 8-Lead SOIC Pin Configuration
GENERAL DESCRIPTION
The AD680 is a band gap voltage reference that provides a fixed
2.5 V output from inputs between 4.5 V and 36 V. The
architecture of the AD680 enables the reference to be operated
at a very low quiescent current while still realizing excellent dc
characteristics and noise performance. Trimming of the high
stability thin-film resistors is performed for initial accuracy and
temperature coefficient, resulting in low errors over temperature.
The precision dc characteristics of the AD680 make it ideal for
use as a reference for DACs that require an external precision
reference. The device is also ideal for ADCs and, in general, can
offer better performance than the standard on-chip references.
Based upon its low quiescent current, which rivals that of many
incomplete 2-terminal references, the AD680 is recommended
for low power applications, such as hand-held, battery-operated
equipment.
A temperature output pin is provided on the 8-lead package
versions of the AD680. The temperature output pin provides an
output voltage that varies linearly with temperature and allows
the AD680 to be configured as a temperature transducer while
providing a stable 2.5 V output.
The AD680 is available in five grades. The AD680AN is speci-
fied for operation from −40°C to +85°C, while the AD680JN is
specified for 0°C to 70°C operation. Both the AD680AN and
AD680JN are available in 8-lead PDIP packages. The AD680AR
is specified for operation from −40°C to +85°C, while the
AD680JR is specified for 0°C to 70°C operation. Both are
available in 8-lead SOIC packages. The AD680JT is specified for
0°C to 70°C operation and is available in a 3-pin TO-92
package.
AD680
BOTTOM VIEW
(Not to Scale)
3
2
1
00813-004
+V
IN
V
OUT
GND
Figure 2. Connection Diagram TO-92
PRODUCT HIGHLIGHTS
1. High Accuracy.
The AD680 band gap reference operates on a very low
quiescent current which rivals that of many 2-terminal
references. This makes the complete, higher accuracy AD680
ideal for use in power-sensitive applications.
2. Low Errors.
Laser trimming of both initial accuracy and temperature coef-
ficients results in low errors over temperature without the use
of external components. The AD680AN and AD680AR have
a maximum variation of 6.25 mV between −40°C and +85°C.
3. Low Noise.
The AD680 noise is low, typically 8 μV p-p from 0.1 Hz to
10 Hz. Spectral density is also low, typically 250 nV/√Hz.
4. Temperature Transducer.
The temperature output pin on the 8-lead package versions
enables the AD680 to be configured as a temperature
transducer.
5. Low Cost.
PDIP packaging provides machine insertability, while SOIC
packaging provides surface-mount capability. TO-92
packaging offers a cost-effective alternative to 2-terminal
references, offering a complete solution in the same package
in which 2-terminal references are usually found.
Rev. H
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2005 Analog Devices, Inc. All rights reserved.
AD680
TABLE OF CONTENTS
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
Output Protection ........................................................................ 4
ESD Caution.................................................................................. 4
Pin Configuration and Connection Diagram............................... 5
Theory of Operation ........................................................................ 6
Applying the AD680 .................................................................... 6
Noise Performance ....................................................................... 6
Turn-on Time................................................................................ 7
Dynamic Performance................................................................. 7
Load Regulation ............................................................................8
Temperature Performance............................................................8
Temperature Output Pin ..............................................................9
Differential Temperature Transducer .........................................9
Low Power, Low Voltage Reference for Data Converters ........9
4.5 V Reference from a 5 V Supply .......................................... 10
Voltage Regulator for Portable Equipment ............................. 10
Outline Dimensions ....................................................................... 11
Ordering Guide .......................................................................... 12
REVISION HISTORY
8/05—Rev. G to Rev. H
Changes to Ordering Guide ..........................................................11
12/04—Rev. F to Rev. G
Updated Format ................................................................. Universal
Changes to Ordering Guide ..........................................................11
5/04—Rev. E to Rev. F
Changes to ORDERING GUIDE ...................................................3
5/03—Rev. D to Rev. E
Changes to ORDERING GUIDE ...................................................3
Added ESD Caution ..........................................................................3
Changes to Figure 20.........................................................................7
Updated OUTLINE DIMENSIONS ...............................................8
7/01—Rev. C to Rev. D
Changes to SPECIFICATIONS........................................................2
Changes to ORDERING GUIDE ....................................................3
Table I added ......................................................................................6
Rev. H | Page 2 of 12
AD680
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
V
IN
to Ground
Power Dissipation (25°C)
Storage Temperature
Lead Temperature (Soldering, 10 sec)
Package Thermal Resistance θ
JA
(All Packages)
Rating
36 V
500 mW
−65°C to +125°C
300°C
120°C/W
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
OUTPUT PROTECTION
Output safe for indefinite short to GND and momentary short
to −V
IN
.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. H | Page 4 of 12
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