1
LM185-2.5/
LM285-2.5/LM385-2.5
APPLICATIO S
U
DESCRIPTIO
U
FEATURES
TYPICAL APPLICATIO
U
Micropower Voltage
Reference
■
Portable Meter References
■
Portable Test Instruments
■
Battery-Operated Systems
■
Panel Meters
■
Current Loop Instrumentation
■
20µA to 20mA Operating Range
■
Guaranteed 1% Initial Voltage Tolerance
■
Guaranteed 1Ω Dynamic Impedance
■
Very Low Power Consumption
The LM185-2.5 is a two-terminal band gap reference
diode that has been designed for applications which
require precision performance with micropower opera-
tion. The device provides guaranteed operation specifica-
tions at currents as low as 20µA. The nominal voltage is
2.5V with both 1% and 2% tolerances available. Some
additional features are: maximum dynamic impedance of
1Ω, low noise and excellent stability over time and tem-
perature. The advanced design, processing and testing
techniques make Linear’s LM185-2.5 a superior choice
over previous designs. A circuit for cold junction compen-
sation of a thermocouple is shown below.
For applications requiring guaranteed temperature drift,
see the LT1034 data sheet.
REVERSE CURRENT (mA)
0
OUTPUT VOLTAGE CHANGE (mV)
4
8
12
16
0.01 1 10 100
LM185-2.5 TA02
–4 0.1
–55°C ≤ T
A
≤ +125°C
Reverse Voltage Change
Thermocouple Cold Junction Compensator
R
SET
2k
450Ω
V
IN
10k ADJUST
FOR 12.17mV
AT 25°C
ACROSS 450Ω
V
–
16k
950Ω
LM385-2.5
100k W.W.
ZERO
1M
2 MERCURY
CELLS 2.6V
METER
+
–
TYPE K
LM185-2.5 TA01
I
Q
≈ 50µA
LM334
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LM185-2.5/
LM285-2.5/LM385-2.5
Reverse Breakdown Current ................................ 30mA
Forward Current .................................................. 10mA
Operating Temperature Range
LM185-2.5 (OBSOLETE)............ –55°C to 125°C
LM285-2.5 ...................................... –40°C to 85°C
LM385-2.5 ........................................... 0°C to 70°C
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
IS
Storage Temperature Range
LM185-2.5 (OBSOLETE)............ –65°C to 150°C
LM285-2.5 .................................... –65°C to 150°C
LM385-2.5 .................................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec.)................ 300°C
WU
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PACKAGE/ORDER I FOR ATIO
LM185H-2.5
LM285H-2.5
LM385H-2.5
LM385BH-2.5
(NOTE 3)
LM285Z-2.5
LM385Z-2.5
LM385BZ-2.5
(NOTE 3)
S8 PART MARKING
2852
3852
3852B
LM285S8-2.5
LM385S8-2.5
LM385BS8-2.5
ORDER PART
NUMBER
ORDER PART
NUMBER ORDER PART
NUMBER
BOTTOM VIEW
Z PACKAGE
3-LEAD TO-92 PLASTIC
BOTTOM VIEW
H PACKAGE
2-LEAD TO-46 METAL CAN
1
2
3
45
6
7
8
TOP VIEW
NC
NC
NC
(DO NOT
USE)
NC
S8 PACKAGE
8-LEAD PLASTIC SO
NC
OBSOLETE PACKAGE
T
JMAX
= 150°C, θ
JA
= 440°C/W, θ
JC
= 80°C/W
T
JMAX
= 150°C, θ
JA
= 220°C/W
T
JMAX
= 100°C, θ
JA
= 160°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
(Note 1)
Consider the S8 or Z Packages for Alternate Source
3
LM185-2.5/
LM285-2.5/LM385-2.5
ELECTRICAL C CHARA TERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
V
Z
Reverse Breakdown Voltage T
A
= 25°C, 20µA ≤ I
R
≤ 20mA
LM185-2.5/285-2.5 2.462 2.500 2.538 V
LM385-2.5 2.425 2.500 2.575 V
LM385B-2.5 (Note 3) 2.462 2.500 2.538 V
∆V
Z
Average Temperature Coefficient 20µA ≤ I
R
≤ 20mA (Note 3) 20 20 ppm/°C
∆Temp
I
MIN
Minimum Operating Current T
MIN
≤ T
A
≤ T
MAX
●
820 820 µA
∆V
Z
Reverse Breakdown Voltage 20µA ≤ I
R
≤ 1mA
∆I
R
Change With Current T
A
= 25°C 1.0 2.0 mV
T
MIN
≤ T
A
≤ T
MAX
●
1.5 2.5 mV
1mA ≤ I
R
≤ 20mA
T
A
= 25°C1020mV
T
MIN
≤ T
A
≤ T
MAX
●
20 25 mV
r
Z
Reverse Dynamic Impedance I
R
= 100µA (Note 4)
T
A
= 25°C 0.2 0.6 0.4 1.0 Ω
T
MIN
≤ T
A
≤ T
MAX
●
1.5 1.5 Ω
e
n
Wide Band Noise (RMS) 10Hz ≤ f ≤ 10kHz, I
R
= 100µA 120 120 µV
∆V
Z
Long Term Stability T
A
= 25°C ± 0.1°C, I
R
= 100µA 20 20 ppm/kHr
∆Time
LM385-2.5/385B-2.5
LM185-2.5/285-2.5
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All specifications are for T
A
= 25°C unless otherwise noted. For the
LM185-2.5 T
MIN
= –55°C and T
MAX
= 125°C. For LM285-2.5, T
MIN
= –
40°C and T
MAX
= 85°C. For LM385-2.5, T
MIN
= 0°C and T
MAX
= 70°C.
Note 3: For very low initial tolerance, consult LT1004 data sheet. The
LT1004 is a low cost, pin for pin substitution device. For guaranteed
temperature coefficient consult the LT1034-2.5 data sheet.
Note 4: Guaranteed but not tested.
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
4
LM185-2.5/
LM285-2.5/LM385-2.5
CCHARA TERISTICS
UW
ATYPICALPER
FORCE
Reverse Characteristics Forward Characteristics Temperature Drift
FORWARD CURRENT (mA)
0.4
FORWARD VOLTAGE (V)
0.8
1.2
1.6
0.01 1 10 100
LM185-2.5 • TPC02
00.1
T
A
= 25°C
TEMPERATURE (°C)
–55
2.480
REFERENCE VOLTAGE (V)
2.485
2.495
2.500
2.505
2.515
–15 25 45 125
LM185-2.5 • TPC03
2.490
2.520
2.525
2.510
–35 5 65 85 105
Reverse Dynamic Impedance Reverse Dynamic Impedance Noise Voltage
FREQUENCY (Hz)
10
DYNAMIC IMPEDANCE (Ω)
100
1k
10k
100k
LM185-2.5 • TPC05
10
1
0.1 100 1k 10k 1M
T
A
= 25°C
I
R
= 100µA
FREQUENCY (Hz)
600
800
1000
1200
1400
10 1k 10k 100k
LM185-2.5M • TPC06
0100
400
200
NOISE (nV/√Hz)
CUTOFF FREQUENCY (Hz)
100
0
INTEGRATED NOISE (µV
RMS
)
80
100
120
100k1k 10k
LM185-2.5 • TPC07
60
40
20
100mA
R
C
RC LOW PASS
TIME (µS)
2.0
3.0
LM185-2.5 • TPC08
1.0
0
0 500
5V
0
4.0
VOLTAGE (V)
100
V
OUT
V
IN
24k
OUTPUT
INPUT
REVERSE CURRENT (mA)
1
DYNAMIC IMPEDANCE (Ω)
10
100
1000
0.01 1 10 100
LM185-2.5 • TPC05
0.1 0.1
f = 25Hz
–55°C TO 125°C
REVERSE VOLTAGE (V)
0
0.1
REVERSE CURRENT (µA)
1
10
100
0.5 1.0 1.5 2.0
LM185-2.5 • TPC01
2.5 3.0
–55°C TO 125°C
Filtered Output Noise Response Time
5
LM185-2.5/
LM285-2.5/LM385-2.5
S
W
A
W
CHETI ICDAGRA
100k
Q2
20pF
7.5k
Q4
Q5
500Ω
60k
Q6
20pF
Q8
600k
Q9
Q11
Q13
200k
50k
300k
Q14
500k
500k
+
–
Q1
Q10
LM185-2.5 SD01
Q3 Q7
Q12
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PACKAGE DESCRIPTIO
OBSOLETE PACKAGE
H Package
2-Lead and 3-Lead TO-46 Metal Can
(Reference LTC DWG # 05-08-1340)
0.016 – 0.021**
(0.406 – 0.533)
DIA
0.025
(0.635)
MAX
0.085 – 0.105
(2.159 – 2.667)
0.500
(12.700)
MIN
0.178 – 0.195
(4.521 – 4.953)
0.209 – 0.219
(5.309 – 5.537) 0.100
(2.540)
TYP
45°
H02/03(TO-46) 1098
0.050
(1.270)
TYP
0.050
(1.270)
TYP
0.028 – 0.048
(0.711 – 1.219)
0.036 – 0.046
(0.914 – 1.168)
FOR 3-LEAD PACKAGE ONLY
REFERENCE
PLANE *
LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE
AND 0.045" BELOW THE REFERENCE PLANE
FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS 0.016 – 0.024
(0.406 – 0.610)
*
**
PIN 1
6
LM185-2.5/
LM285-2.5/LM385-2.5
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
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PACKAGE DESCRIPTIO
0.016 – 0.050
(0.406 – 1.270)
0.010 – 0.020
(0.254 – 0.508)× 45°
0°– 8° TYP
0.008 – 0.010
(0.203 – 0.254)
SO8 1298
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
TYP
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
BSC
1234
0.150 – 0.157**
(3.810 – 3.988)
8765
0.189 – 0.197*
(4.801 – 5.004)
0.228 – 0.244
(5.791 – 6.197)
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
*
**
7
LM185-2.5/
LM285-2.5/LM385-2.5
Z Package
3-Lead Plastic TO-92 (Similar to TO-226)
(Reference LTC DWG # 05-08-1410)
0.050
(1.27)
BSC
0.060 ± 0.005
(1.524± 0.127)
DIA
0.90
(2.286)
NOM
0.180 ± 0.005
(4.572 ± 0.127)
0.180 ± 0.005
(4.572 ± 0.127)
0.500
(12.70)
MIN
0.050
(1.270)
MAX
UNCONTROLLED
LEAD DIMENSION
0.016 ± 0.003
(0.406 ± 0.076)
5°
NOM
0.015 ± 0.002
(0.381 ± 0.051)
0.060 ± 0.010
(1.524 ± 0.254)
10° NOM
0.140 ± 0.010
(3.556 ± 0.127)
Z3 (TO-92) 0401
0.098 +016/–0.04
(2.5 +0.4/–0.1)
2 PLCS
TO-92 TAPE AND REEL
REFER TO TAPE AND REEL SECTION OF
LTC DATA BOOK FOR ADDITIONAL INFORMATION
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PACKAGE DESCRIPTIO
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
8
LM185-2.5/
LM285-2.5/LM385-2.5
LINEAR TECHNOLOGY CORPORATION 1992
185fc LT/CP 0801 1.5K REV C • PRINTED IN USA
220k
9V
2.5V
LM385-2.5
REFERENCE FROM
A 9V BATTERY
2.7k
V
+
2.5V
LM385-2.5
OPERATION OVER A
WIDE SUPPLY RANGE
R
3.7V ≤ V
+
≤ 30V
LM185-2.5 TA03
LM334
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SA
O
PPLICATITYPICAL
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT1634 Micropower Shunt Voltage Reference 0.05% Initial Accuracy, 10ppm/°C Maximum Tempco
Output Voltage: 1.25V, 2.5V, 4.096V and 5V
