LM285 2.5, LM385 2.5, LM385B 2.5
MICROPOWER VOLTAGE REFERENCES
SLVS023J − JANUARY 1989 − REVISED MARCH 2005
D
Operating Current Range . . . 20
µA
to
D
D
20 mA
1.5% and 3% Initial Voltage Tolerance
Reference Impedance
− LM385 . . . 1
Ω
Max at 25°C
− All Devices . . . 1.5
Ω
Max Over Full
Temperature Range
Very Low Power Consumption
Applications
− Portable Meter References
− Portable Test Instruments
− Battery-Operated Systems
− Current-Loop Instrumentation
− Panel Meters
Interchangeable With Industry-Standard
LM285-2.5 and LM385-2.5
LM285-2.5 . . . D PACKAGE
LM385-2.5, LM385B-2.5 . . . D OR PW PACKAGE
(TOP VIEW)
NC
NC
NC
ANODE
1
2
3
4
8
7
6
5
CATHODE
NC
NC
NC
D
D
NC − No internal connection
LM285-2.5, LM385-2.5, LM385B-2.5 . . . LP PACKAGE
(TOP VIEW)
ANODE
CATHODE
NC
NC − No internal connection
D
description/ordering information
These micropower two-terminal band-gap voltage references operate over a 20-µA to 20-mA current range and
feature exceptionally low dynamic impedance and good temperature stability. On-chip trimming provides tight
voltage tolerance. The band-gap reference for these devices has low noise and long-term stability.
ORDERING INFORMATION
TA
VZ
TOLERANCE
SOIC (D)
3%
TO226/TO-92 (LP)
TSSOP (PW)
0°C to 70°C
SOIC (D)
1.5%
TO226/TO-92 (LP)
TSSOP (PW)
SOIC (D)
−40°C to 85°C
1.5%
TO226/TO-92 (LP)
PACKAGE†
Tube of 75
Reel of 2000
Tube of 1000
Reel of 2000
Tube of 150
Reel of 2000
Tube of 75
Reel of 2000
Tube of 1000
Reel of 2000
Tube of 150
Reel of 2000
Tube of 75
Reel of 2000
Tube of 1000
Reel of 2000
ORDERABLE
PART NUMBER
LM385D-2-5
LM385DR-2-5
LM385LP-2-5
LM385LPR-2-5
LM385PW-2-5
LM385PWR-2-5
LM385BD-2-5
LM385BDR-2-5
LM385BLP-2-5
LM385BLPR-2-5
LM385BPW-2-5
LM385BPWR-2-5
LM285D-2-5
LM285DR-2-5
LM285LP-2-5
LM285LPR-2-5
285-25
285-25
285-25
385B25
385-25
385B25
385-25
385-25
385-25
TOP-SIDE
MARKING
† Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at
www.ti.com/sc/package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright
2005, Texas Instruments Incorporated
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
1
LM285 2.5, LM385 2.5, LM385B 2.5
MICROPOWER VOLTAGE REFERENCES
SLVS023J − JANUARY 1989 − REVISED MARCH 2005
description/ordering information (continued)
The design makes these devices exceptionally tolerant of capacitive loading and, thus, easier to use in most
reference applications. The wide dynamic operating temperature range accommodates varying current
supplies, with excellent regulation.
The extremely low power drain of this series makes them useful for micropower circuitry. These voltage
references can be used to make portable meters, regulators, or general-purpose analog circuitry, with battery
life approaching shelf life. The wide operating current range allows them to replace older references with
tighter-tolerance parts.
symbol
ANODE
CATHODE
schematic
CATHODE
7.5 kΩ
600 kΩ
Q12
Q13
Q4
Q7
Q11
200 kΩ
Q3
Q10
Q1
20 pF
Q2
Q5
Q6
Q8
20 pF
Q9
50 kΩ
300 kΩ
500
Ω
Q14
100 kΩ
500
Ω
60 kΩ
500
Ω
ANODE
NOTE A: All component values shown are nominal.
2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
LM285 2.5, LM385 2.5, LM385B 2.5
MICROPOWER VOLTAGE REFERENCES
SLVS023J − JANUARY 1989 − REVISED MARCH 2005
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
†
Reverse current, I
R
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mA
Forward current, I
F
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA
Package thermal impedance,
θ
JA
(see Notes 1 and 2): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97°C/W
LP package . . . . . . . . . . . . . . . . . . . . . . . . . . 140°C/W
PW package . . . . . . . . . . . . . . . . . . . . . . . . . 149°C/W
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
Storage temperature range, T
stg
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTES: 1. Maximum power dissipation is a function of TJ(max)
,
θ
JA
,
and TA. The maximum allowable power dissipation at any allowable ambient
temperature is PD = (TJ(max) − TA)/
θ
JA. Operation at the absolute maximum TJ of 150°C can affect reliability.
2. The package thermal impedance is calculated in accordance with JESD 51-7.
recommended operating conditions
MIN
IZ
TA
Reference current
Operating free-air temperature range
LM285-2.5
LM385-2.5, LM385B-2.5
0.02
−40
0
MAX
20
85
70
UNIT
mA
°C
electrical characteristics at specified free-air temperature
PARAMETER
VZ
Reference
voltage
Average
temperature
coefficient of
reference
voltage§
Change in
reference
voltage with
current
Long-term
change in
reference
voltage
Minimum
reference
current
Reference
impedance
Broadband
noise
voltage
IZ = 100
µA
A
IZ = 100
µA,
f = 10 Hz
to 10 kHz
TEST
CONDITIONS
IZ = 20
µA
to 20 mA
IZ = 20
µA
to 20 mA
TA‡
25°C
LM285-2.5
MIN
2.462
TYP
2.5
MAX
2.538
LM385-2.5
MIN
2.425
TYP
2.5
MAX
2.575
LM385B-2.5
MIN
2.462
TYP
2.5
MAX
2.538
UNIT
V
α
VZ
Full range
±20
±20
±20
ppm/°C
∆V
Z
IZ = 20
µA
to 1 mA
IZ = 1 mA
to 20 mA
25°C
Full range
25°C
Full range
±20
1
1.5
10
30
±20
2
2
20
30
±20
2
2
20
30
mV
∆V
Z/∆t
IZ = 100
µA
25°C
ppm/khr
IZ(min)
Full range
25°C
Full range
25°C
8
0.2
20
0.6
1.5
8
0.4
20
1
1.5
8
0.4
20
1
1.5
µA
zz
Vn
Ω
µV
120
120
120
‡ Full range is 0°C to 70°C for the LM385-2.5 and LM385B-2.5, and −40°C to 85°C for the LM285-2.5.
§ The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified temperature
range.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
3
LM285 2.5, LM385 2.5, LM385B 2.5
MICROPOWER VOLTAGE REFERENCES
SLVS023J − JANUARY 1989 − REVISED MARCH 2005
TYPICAL CHARACTERISTICS
†
REVERSE CURRENT
vs
REVERSE VOLTAGE
100
TA = −55°C to 125°C
∆V
Z − Reference Voltage Change − mV
12
16
TA = −55°C to 125°C
REFERENCE VOLTAGE CHANGE
vs
REVERSE CURRENT
I R − Reverse Current −
µ
A
10
8
1
4
0
0.1
0
0.5
1
1.5
2
2.5
3
VR − Reverse Voltage − V
−4
0.01
0.1
1
10
100
IR − Reverse Current − mA
Figure 1
FORWARD VOLTAGE
vs
FORWARD CURRENT
1.6
TA = 25°C
1.4
V F − Forward Voltage − V
1.2
1
0.8
0.6
0.4
0.2
0
0.01
VZ − Reference Voltage − V
2.525
Figure 2
REFERENCE VOLTAGE
vs
FREE-AIR TEMPERATURE
IZ = 20
µA
to 20 mA
2.52
2.515
2.51
2.505
2.5
2.495
2.49
2.485
0.1
1
10
100
2.48
− 55 − 35 − 15
5
25
45
65
85
105 125
IF − Forward Current − mA
TA − Free-Air Temperature −
°C
Figure 3
Figure 4
† Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.
4
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
LM285 2.5, LM385 2.5, LM385B 2.5
MICROPOWER VOLTAGE REFERENCES
SLVS023J − JANUARY 1989 − REVISED MARCH 2005
TYPICAL CHARACTERISTICS
†
REFERENCE IMPEDANCE
vs
REFERENCE CURRENT
1000
f = 25 Hz
TA = MIN to MAX‡
z z − Reference Impedance −
Ω
100
z z − Reference Impedance −
Ω
1k
10 k
IZ = 100
µA
TA = 25°C
REFERENCE IMPEDANCE
vs
FREQUENCY
100
10
10
1
1
0.1
0.01
0.1
1
10
100
0.1
0.01
0.1
1
10
100
1000
Iz − Reference Current − mA
f − Frequency − kHz
Figure 5
NOISE VOLTAGE
vs
FREQUENCY
1400
1200
Vn − Noise Voltage − nV/ Hz
IZ = 100
µA
TA = 25°C
120
100
µA
Filtered RMS Output Noise Voltage −
µ
V
100
R
C
80
Figure 6
FILTERED RMS OUTPUT NOISE VOLTAGE
vs
FREQUENCY
TA = 25°C
RC Low Pass
1000
800
60
600
40
400
200
0
10
20
100
1k
f − Frequency − Hz
10 k
100 k
0
0.1
1
10
100
f − Frequency − kHz
Figure 7
Figure 8
† Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.
‡ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
5
ADI Reference Circuit
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