LM185-2.5/LM285-2.5/LM385-2.5
Micropower Voltage Reference Diode
General Description
The
LM185-2.5/LM285-2.5/LM385-2.5
are
micropower
2-terminal band-gap voltage regulator diodes. Operating
over a 20 A to 20 mA current range, they feature excep-
tionally low dynamic impedance and good temperature sta-
bility. On-chip trimming is used to provide tight voltage toler-
ance. Since the LM-185-2.5 band-gap reference uses only
transistors and resistors, low noise and good long term
stability result.
Careful design of the LM185-2.5 has made the device ex-
ceptionally tolerant of capacitive loading, making it easy to
use in almost any reference application. The wide dynamic
operating range allows its use with widely varying supplies
with excellent regulation.
The extremely low power drain of the LM185-2.5 makes it
useful for micropower circuitry. This voltage reference can be
used to make portable meters, regulators or general purpose
analog circuitry with battery life approaching shelf life. Fur-
ther, the wide operating current allows it to replace older
references with a tighter tolerance part. For applications
requiring 1.2V see LM185-1.2.
The LM185-2.5 is rated for operation over a -55C to 125C
temperature range while the LM285-2.5 is rated -40C to
85C and the LM385-2.5 0C to 70C. The LM185-2.5/
LM285-2.5 are available in a hermetic TO-46 package and
the LM285-2.5/LM385-2.5 are also available in a low-cost
TO-92 molded package, as well as S.O. and SOT-23. The
LM185-2.5 is also available in a hermetic leadless chip
carrier package.
Features
n
20 mV (
0.8%) max. initial tolerance (A grade)
n
Operating current of 20 A to 20 mA
n
0.6
dynamic impedance (A grade)
n
Low temperature coefficient
n
Low voltage reference -- 2.5V
n
1.2V device and adjustable device also
available -- LM185-1.2 series and LM185 series,
respectively
Connection Diagrams
TO-92
Plastic Package
SO Package
00551908
Bottom View
Order Number LM285Z-2.5,
LM285BXZ-2.5, LM285BYZ-2.5
LM385Z-2.5, LM385AXZ-2.5
LM385AYZ-2.5, LM385BZ-2.5,
LM385BXZ-2.5 or LM385BYZ-2.5
See NS Package Number Z03A
00551911
Order Number LM285M-2.5,
LM285BXM-2.5, LM285BYM-2.5
LM385M-2.5, LM385BM-2.5
LM385BXM-2.5 or LM385BYM-2.5
See NS Package Number M08A
SOT-23
00551929
* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating.
Order Number LM385M3-2.5
See NS Package Number MA03B
February 2005
LM185-2.5/LM285-2.5/LM385-2.5
Micropower
V
oltage
Reference
Diode
2005 National Semiconductor Corporation
DS005519
www.national.com
Connection Diagrams
(Continued)
LCC
Leadless Chip Carrier
TO-46
Metal Can Package
00551914
Order Number LM185E-2.5/883
See NS Package Number E20A
00551913
Bottom View
Order Number LM185H-2.5,
LM185H-2.5/883, LM185BXH-2.5,
LM185BXH-2.5/883, LM185BYH-2.5,
LM185BYH2.5/883, LM285H-2.5,
or LM285BYH-2.5
See NS Package Number H02A
LM185-2.5/LM285-2.5/LM385-2.5
www.national.com
2
Absolute Maximum Ratings
(Notes 1,
2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Reverse Current
30 mA
Forward Current
10 mA
Operating Temperature
Range (Note 3)
LM185-2.5
-55C to + 125C
LM285-2.5
-40C to + 85C
LM385-2.5
0C to 70C
Storage Temperature
-55C to + 150C
Soldering Information
TO-92 Package (10 sec.)
260C
TO-46 Package (10 sec.)
300C
SO and SOT Package
Vapor Phase (60 sec.)
215C
Infrared (15 sec.)
220C
See AN-450 "Surface Mounting Methods and Their Effect on
Product Reliability" for other methods of soldering surface
mount devices.
Electrical Characteristics
(Note 4)
Parameter
Conditions
Typ
LM385A-2.5
Units
(Limits)
LM385AX-2.5
LM385AY-2.5
Tested
Design
Limit
Limit
(Note 5)
(Note 6)
Reverse Breakdown
I
R
= 100 A
2.500
2.480
V(Min)
Voltage
2.520
V(Max)
2.500
2.470
V(Min)
2.530
V(Max)
Minimum Operating
12
18
20
A
Current
(Max)
Reverse Breakdown
I
MIN
I
R
1mA
1
1.5
mV
Voltage Change with
(Max)
Current
1 mA
I
R
20 mA
10
20
mV
(Max)
Reverse Dynamic
I
R
= 100 A,
0.2
0.6
Impedance
f = 20 Hz
1.5
Wideband Noise (rms)
I
R
= 100 A
120
V
10 Hz
f 10 kHz
Long Term Stability
I
R
= 100 A,
T = 1000 Hr,
20
ppm
T
A
= 25C
0.1C
Average Temperature
I
MIN
I
R
20 mA
Coefficient (Note 7)
X Suffix
30
ppm/C
Y Suffix
50
(Max)
All Others
150
LM185-2.5/LM285-2.5/LM385-2.5
www.national.com
3
Electrical Characteristics
LM185-2.5
LM185BX-2.5
LM385B-2.5
LM185BY-2.5
LM385BX-2.5
LM385-2.5
Units
LM285-2.5
LM385BY-2.5
(Limit)
Parameter
Conditions
Typ
LM285BX-2.5
LM285BY-2.5
Tested
Design
Tested
Design
Tested Design
Limit
Limit
Limit
Limit
Limit
Limit
(Note 5) (Note
8)
(Note
6)
(Note
5)
(Note 6)
(Note
5)
(Note
6)
Reverse
Breakdown
T
A
= 25C,
2.5
2.462
2.462
2.425
V(Min)
Voltage
20 A
I
R
20
mA
2.538
2.538
2.575
V(Max)
Minimum
Operating
Current
13
20
30
20
30
20
30
A
(Max)
LM385M3-2.5
15
20
Reverse
Breakdown
Voltage Change
with Current
20 A
I
R
1
mA
1
1.5
2.0
2.5
2.0
2.5
mV
(Max)
1 mA
I
R
20
mA
10
20
20
25
20
25
mV
(Max)
Reverse
Dynamic
I
R
= 100 A,
1
Impedance
f = 20 Hz
Wideband
Noise (rms)
I
R
= 100 A,
120
V
10 Hz
f 10
kHz
Long Term
Stability
I
R
= 100 A,
T = 1000 Hr,
20
ppm
T
A
= 25C
0.1C
Average
Temperature
I
R
= 100 A
Coefficient
(Note 7)
X Suffix
30
30
ppm/C
Y Suffix
50
50
ppm/C
All Others
150
150
150
ppm/C
(Max)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed.
Note 2: Refer to RETS185H-2.5 for military specifications.
Note 3: For elevated temperature operation, T
J MAX
is:
LM185
150C
LM285
125C
LM385
100C
Thermal Resistance
TO-92
TO-46
SO-8
SOT-23
ja
(Junction to Ambient)
180C/W (0.4" Leads)
440C/W 165C/W
283C/W
170C/W (0.125" Leads)
jc
(Junction to Case)
N/A
80C/W
N/A
N/A
LM185-2.5/LM285-2.5/LM385-2.5
www.national.com
4
Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at T
A
= T
J
= 25C.
Note 5: Guaranteed and 100% production tested.
Note 6: Guaranteed, but not 100% production tested. These limits are not used to calculate average outgoing quality levels.
Note 7: The average temperature coefficient is defined as the maximum deviation of reference voltage at all measured temperatures between the operating T
MAX
and T
MIN
, divided by T
MAX
T
MIN
. The measured temperatures are -55C, -40C, 0C, 25C, 70C, 85C, 125C.
Note 8: A military RETS electrical specification available on request.
Typical Performance Characteristics
Reverse Characteristics
Reverse Characteristics
00551915
00551916
Forward Characteristics
Temperature Drift
00551917
00551918
Reverse Dynamic
Impedance
Reverse Dynamic
Impedance
00551919
00551920
LM185-2.5/LM285-2.5/LM385-2.5
www.national.com
5
PDF 
ZIP