Updates to Packages ....................................................................... 10
Rev. I | Page 2 of 12
Data Sheet
SPECIFICATIONS
T
A
= 25°C, V
IN
= 5 V, unless otherwise noted.
Table 1.
Parameter
OUTPUT VOLTAGE
2.5 V Out
3.0 V Out
SOLDER HEAT SHIFT
Mean
Sigma
OUTPUT VOLTAGE DRIFT
1
−40°C to +85°C
−55°C to +125°C
LINE REGULATION
2.5 V Output, 4 V ≤+V
IN
≤ 36 V, T
MIN
to T
MAX
3.0 V Output, 4.5 V ≤+V
IN
≤ 36 V, T
MIN
to T
MAX
LOAD REGULATION, SERIES MODE
Sourcing 0 mA < I
OUT
< 10 mA
T
MIN
to T
MAX
Sinking −10 mA < I
OUT
< 0 mA
−40°C to +85°C
−55°C to +125°C
LOAD REGULATION, SHUNT MODE
I < I
SHUNT
< 10 mA
QUIESCENT CURRENT, 2.5 V SERIES MODE
2
–40°C to +85°C
−55°C to +125°C
MINIMUM SHUNT CURRENT
OUTPUT NOISE
0.1 Hz to 10 Hz
Spectral Density, 100 Hz
LONG-TERM STABILITY
3
TRIM RANGE
TEMPERATURE PIN
Voltage Output @ 25°C
Temperature Sensitivity
Output Resistance
SHORT-CIRCUIT CURRENT TO GROUND
TEMPERATURE RANGE
Specified Performance (A, B, C)
Operating Performance (A, B, C)
4
1
2
AD780
AD780AN/AD780AR
Min
Typ Max
2.495
2.995
−1.1
0.4
7
20
10
10
50
75
75
75
150
75
0.75
0.8
0.7
4
100
20
4.0
500
560
1.9
3
30
620
1.0
1.3
1.0
2.505
3.005
Min
2.4985
2.9950
AD780CR
Typ Max
2.5015
3.0050
−1.1
0.4
7
20
10
10
50
75
75
75
150
75
0.75
0.8
0.7
4
100
20
1.0
1.3
1.0
AD780BN/AD780BR
Min
Typ Max
2.499
2.999
−1.1
0.4
3
2.501
3.001
Unit
V
V
mV
mV
ppm/°C
ppm/°C
μV/V
μV/V
μV/mA
μV/mA
μV/mA
μV/mA
μV/mA
μV/mA
mA
mA
mA
μV p-p
nV/√Hz
± ppm/1000 Hr
±%
10
10
50
75
75
75
150
75
0.75
0.8
0.7
4
100
20
4.0
1.0
1.3
1.0
4.0
500
560
1.9
3
30
620
500
560
1.9
3
30
620
mV
mV/°C
kΩ
mA
°C
°C
−40
−55
+85
+125
−40
−55
+85
+125
−40
−55
+85
+125
Maximum output voltage drift is guaranteed for all packages.
3.0 V mode typically adds 100 μA to the quiescent current. Also, I
q
increases by 2 μA/V above an input voltage of 5 V.
3
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
4
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.
Rev. I | Page 3 of 12
AD780
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
+V
IN
to Ground
TRIM Pin to Ground
TEMP Pin to Ground
Power Dissipation (25°C)
Storage Temperature
Lead Temperature
(Soldering 10 sec)
Output Protection
ESD Classification
Values
36 V
36 V
36 V
500 mW
−65°C to +150°C
300°C
Output safe for indefinite short to
ground and momentary short to V
IN
.
Class 1 (1000 V)
TRIM
V
OUT
96 mils
GND
TEMP
+V
IN
Data Sheet
67 mils
GND
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
DNC
1
+V
IN 2
TEMP
3
2.5V/3.0V O/PSELECT
(DNC OR GND)
7
DNC
8
2.5V/3.0V
O/P SELECT
Figure 3. Die Layout
NOTES
Both V
OUT
pads must be connected to the output.
Die Thickness: The standard thickness of Analog Devices, Inc.
bipolar dice is 10 mil ± 1 mil.
Die Dimensions: The dimensions given are the maximum possible
die size.
Backing: The standard backside surface is silicon (not plated).
Analog Devices does not recommend gold-backed dice for most
applications.
Edges: A diamond saw is used to separate wafers into dice, thus
providing perpendicular edges halfway through the die. In
contrast to scribed dice, this technique provides a more uniform
die shape and size. The perpendicular edges facilitate handling
(such as tweezer pickup), while the uniform shape and size
simplify substrate design and die attach.
Top Surface: The standard top surface of the die is covered by a
layer of passivation. All areas are covered except bonding pads
and scribe lines.
Surface Metallization: The metallization to Analog Devices
bipolar dice is aluminum/copper. The minimum thickness is
10,000 Å.
Bonding Pads: All bonding pads have a minimum size of
4.0 mil by 6.0 mil. The passivation windows have a minimum
size of 3.5 mil by 5.3 mil.
AD780
6
V
OUT
TOP VIEW
(Not to Scale)
5
TRIM
GND
4
00841-002
NOTES
1. DNC = DO NOT CONNECT TO THIS PIN.
Figure 2. Pin Configuration, 8-Lead PDIP and SOIC Packages
THERMAL RESISTANCE
Thermal performance is directly linked to PCB design and
operating environment. Careful attention to PCB thermal
design is required.
Table 3. Thermal Resistance
1
Package Type
N-8
R-8
1
θ
JA
49.8
160
θ
JC2
37.4
36.8
Unit
°C/W
°C/W
Values in Table 3 are calculated based on standard JEDEC test conditions
unless otherwise specified.
2
100um TIM is used for the θ
JC
test. TIM is assumed to have 3.6 W/mK.
Table 4. Die Physical Characteristics
Parameter
Die Size
Back Grind Thickness
Bond Pad Opening Size
Top Metal Composition
Passivation
Polyimide
Die Marker
Substrate Bias
Value
67 × 96
10
89 × 136
AlCu (0.5%)
Oxynitride
None
780
GND
Units
mil
mil
µm
%
µm
V
ESD CAUTION
Rev. I | Page 4 of 12
00841-003
Data Sheet
THEORY OF OPERATION
Band gap references are the high performance solution for low
supply voltage and low power voltage reference applications. In
this technique, a voltage with a positive temperature coefficient
is combined with the negative coefficient of a transistor’s V
be
to
produce a constant band gap voltage.
In the
AD780,
the band gap cell contains two NPN transistors
(Q6 and Q7) that differ in emitter area by 12×. The difference in
their V
be
s produces a PTAT current in R5. This, in turn, produces a
PTAT voltage across R4 that, when combined with the V
be
of
Q7, produces a voltage (V
bg
) that does not vary with temperature.
Precision laser trimming of the resistors and other patented circuit
techniques are used to further enhance the drift performance.
+V
IN
2
AD780
The output voltage of the
AD780
is determined by the
configuration of Resistors R13, R14, and R15 in the amplifier’s
feedback loop. This sets the output to either 2.5 V or 3.0 V,
depending on whether R15 (Pin 8) is grounded or not connected.
A unique feature of the
AD780
is the low headroom design of
the high gain amplifier, which produces a precision 3 V output
from an input voltage as low as 4.5 V (or 2.5 V from a 4.0 V
input). The amplifier design also allows the part to work with
+V
IN
= V
OUT
when current is forced into the output terminal.
This allows the
AD780
to work as a 2-terminal shunt regulator,
providing a −2.5 V or −3.0 V reference voltage output without
external components.
The PTAT voltage is also used to provide the user with a
thermometer output voltage (at Pin 3) that increases at a rate of
approximately 2 mV/°C.
The DNC (Pin 7) of the
AD780
is a 20 kΩ resistor to +V
IN
that
is used solely for production test purposes. Users who are currently
using the LT1019 self-heater pin (Pin 7) must take into account
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