Low Power, Low Cost
2.5 V Reference
AD680
Rev. H
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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
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.
CONNECTION DIAGRAMS
TP DENOTES FACTORY TEST POINT.
NO CONNECTIONS SHOULD BE MADE
TO THESE PINS.
NC = NO CONNECT
AD680
TOP VIEW
(Not to Scale)
TP*
1
+V
IN
2
TEMP
3
GND
4
TP*
TP*
V
OUT
NC
8
7
6
5
00813-003
Figure 1. 8-Lead PDIP and 8-Lead SOIC Pin Configuration
00813-004
AD680
BOTTOM VIEW
(Not to Scale)
32
1
+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.
