ANALOG DEVICES AD680 Service Manual
Low Power, Low Cost
*
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FEATURES
Low quiescent current at 250 μA max
Laser trimmed to high accuracy
± 5 mV max (AN, AR grades)
2.5 V
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-lea
d PDIP, 8-lead SOIC, and 3-pin TO-92
GENERAL DESCRIPTION
The AD6801 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
e as a reference for DACs that require an external precision
us
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
v
ersions 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-
ied for operation from −40°C to +85°C, while the AD680JN is
f
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.
1
Protected by U.S. Patent Nos. 4,902,959; 4,250,445; and 4,857,862.
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.
2.5 V Reference
CONNECTION DIAGRAMS
1
TP*
+V
2
IN
AD680
3
TEMP
GND
TP DENOTES FACTORY TEST POINT.
NO CONNECTIONS SHOULD BE MADE
TO THESE PINS.
Figure 1. 8-Lead PDIP and 8-Lead SOIC Pin Configuration
Figure 2. Connection Diagram TO-92
TOP VIEW
(Not to Scale)
4
NC = NO CONNECT
AD680
BOTTOM VIEW
(Not to Scale)
32
+VINV
OUT
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.
aser trimming of both initial accuracy and temperature coef-
L
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
10 Hz. Spectral density is also low, typically 250 nV/√Hz.
4. Temperature Transducer.
The t
enables the AD680 to be configured as a temperature
transducer.
5. Low Cost.
P
DIP 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.
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.
noise is low, typically 8 μV p-p from 0.1 Hz to
emperature output pin on the 8-lead package versions
1
GND
TP*
8
TP*
7
6
V
OUT
5
NC
00813-004
AD680
00813-003
AD680
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TABLE OF CONTENTS
Specifications..................................................................................... 3
Load Regulation ............................................................................8
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
REVISION HISTORY
8/05—Rev. G to Rev. H
Changes to Ordering Guide ..........................................................11
12/04—Rev. F to Rev. G
U
pdated Format ................................................................. Universal
Changes to Ordering Guide ..........................................................11
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
5/04—Rev. E to Rev. F
hanges to ORDERING GUIDE ...................................................3
C
5/03—Rev. D to Rev. E
hanges to ORDERING GUIDE ...................................................3
C
Added ESD Caution..........................................................................3
Changes to Figure 20.........................................................................7
Updated OUTLINE DIMENSIONS ...............................................8
7/01—Rev. C to Rev. D
hanges to SPECIFICATIONS........................................................2
C
Changes to ORDERING GUIDE ....................................................3
Table I added ......................................................................................6
Rev. H | Page 2 of 12
AD680
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SPECIFICATIONS
TA = 25°C, VIN = 5 V, unless otherwise noted. Specifications in boldface are tested on all production units at final electrical test. Results
from these tests are used to calculate outgoing quality levels. All minimum and maximum specifications are guaranteed.
Table 1.
AD680AN/AD680AR AD680JN/AD680JR AD680JT
Parameter Min Typ Max Min Typ Max Min Typ Max Unit
OUTPUT VOLTAGE
Output Voltage, V
Initial Accuracy, V
O
OERR
−0.20 +0.20 −0.40 +0.40 −0.40 +0.40 %
OUTPUT VOLTAGE DRIFT
1
0°C to 70°C 10 10 25 10 30 ppm/°C
−40°C to +85°C 20 25 25 ppm/°C
LINE REGULATION
4.5 V ≤ +VIN ≤ 15 V 40 40 40 μV/V
(@ T
to T
MIN
) 40 40 40 μV/V
MAX
15 V ≤ +VIN ≤ 36 V 40 40 40 μV/V
(@ T
to T
MIN
) 40 40 40 μV/V
MAX
LOAD REGULATION
0 < I
< 10 mA 80 100 80 100 80 100 μV/mA
OUT
(@ T
to T
MIN
) 80 100 80 100 80 100 μV/mA
MAX
QUIESCENT CURRENT 195
(@ T
to T
MIN
) 280 280 280 μA
MAX
POWER DISSIPATION 1
OUTPUT NOISE
0.1 Hz to 10 Hz 8 10 8 10 8 10 μV p-p
Spectral Density, 100 Hz 250 250 250 nV/√Hz
CAPACITIVE LOAD 50 50 50 nF
LONG-TERM STABILITY 25 25 25 ppm/1,000 hr
SHORT-CIRCUIT CURRENT TO GROUND 25 50 25 50 25 50 mA
TEMPERATURE PIN
Voltage Output @ 25°C 540 596 660 540 596 660 mV
Temperature Sensitivity 2 2 mV/°C
Output Current −5 +5 −5 +5 μA
Output Resistance 12 12 kΩ
TEMPERATURE RANGE
Specified Performance −40 +85 0 70 0 70 °C
Operating Performance
1
Maximum output voltage drift is guaranteed for all packages.
2
The operating temperature range is defined as the temperature extremes at which the device will still function. Parts may deviate from their specified performance
outside their specified temperature range.
2
2.495 2.500 2.505 2.490 2.500 2.510 2.490 2.500 2.510 V
−5 +5 −10 +10 −10 +10 mV
250
1.25
195
1
250
1.25
195
1
250
1.25
μA
mW
−40 +85 −40 +85 −40 +85 °C
Rev. H | Page 3 of 12
AD680
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ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
VIN to Ground 36 V
Power Dissipation (25°C) 500 mW
Storage Temperature −65°C to +125°C
Lead Temperature (Soldering, 10 sec) 300°C
Package Thermal Resistance θJA (All Packages) 120°C/W
Stresses above those listed under Absolute Maximum Ratings
ma
y 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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