LM185-1.2/
LM285-1.2/LM385-1.2
Micropower Voltage
Reference
FEATURES
s
s
s
s
DESCRIPTIO
10µA to 20mA Operating Range
Guaranteed
1% Initial Voltage Tolerance
Guaranteed
1Ω Dynamic Impedance
Very Low Power Consumption
APPLICATIO S
s
s
s
s
Portable Meter References
Portable Test Instruments
Battery Operated Systems
Current Loop Instrumentation
The LM185-1.2 is a two terminal band gap reference diode
that has been designed for applications which require
precision performance with micropower operation. The
device provides guaranteed operating specifications at
currents as low as 10µA. The nominal voltage is 1.235V
with both 1% and 2% tolerances available. Some addi-
tional features are: maximum dynamic impedance of 1Ω,
low noise and excellent stability over time and tempera-
ture. Advanced design, processing and testing techniques
make Linear’s LM185-1.2 a superior choice over previous
designs. A micropower 5V reference application is shown
below. For guaranteed TC, micropower references, see the
LT1034 data sheet.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Micropower 5V Reference
V
IN
7V TO 15V
OUTPUT VOLTAGE CHANGE (mV)
Reverse Voltage Change with Current
10
8
6
4
2
0
–2
0.01
T
A
= 25°C
V
+
LM334
V
–
R
5.6k
3
+
–
7
LT1494
6
5V
150pF
3.01M
1%
LM385-1.2
1M
1%
2
4
185/285/385 TA01a
U
0.1
1
10
REVERSE CURRENT (mA)
100
185/285/385 TA01b
U
U
1
LM185-1.2/
LM285-1.2/LM385-1.2
ABSOLUTE
AXI U RATI GS
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Reverse Breakdown Current ................................. 30mA
Forward Current ................................................... 10mA
Operating Temperature Range
LM185-1.2(OBSOLETE)
...............
–55°C to 125°C
LM285-1.2 ..........................................–40°C to 85°C
LM385-1.2 .............................................. 0°C to 70°C
PACKAGE/ORDER I FOR ATIO
BOTTOM VIEW
ORDER PART
NUMBER
LM185H-1.2
LM285H-1.2
LM385H-1.2
LM385BH-1.2
1
2
H PACKAGE
2-LEAD TO-46 METAL CAN
T
JMAX
= 150°C,
θ
JA
= 440°C/W,
θ
JC
= 80°C/W
(NOTE 3)
OBSOLETE PACKAGE
Consider the S8 or Z Packages for Alternate Source
TOP VIEW
NC 1
NC 2
NC 3
4
8
7 NC
6
5 NC
(DO
S8 PACKAGE NOT USE)
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 190°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
2
U
U
W
W W
U
W
BOTTOM VIEW
ORDER PART
NUMBER
LM285Z-1.2
LM385Z-1.2
LM385BZ-1.2
Z PACKAGE
3-LEAD PLASTIC TO-92
T
JMAX
= 150°C,
θ
JA
= 160°C/W
(NOTE 3)
ORDER PART
NUMBER
LM385BS8-1.2
LM385S8-1.2
S8 PART
MARKING
3851
3851B
LM185-1.2/
LM285-1.2/LM385-1.2
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. For the LM185-1.2 T
MIN
= –55°C and T
MAX
= 125°C. For LM285-1.2
T
MIN
= –40°C and T
MAX
= 85°C.For LM385-1.2 T
MIN
= 0°C and T
MAX
= 70°C. For MIL-STD components, please refer to LTC883C data
sheet for test listing and parameters.
SYMBOL
V
Z
PARAMETER
Reverse Breakdown Voltage
CONDITIONS
T
A
= 25°C, I
MIN
≤
I
R
≤
20mA
LM185-1.2
LM385-1.2
LM385B-1.2 (Note 3)
I
MIN
≤
I
R
≤
20mA (Notes 2, 3)
T
MIN
≤
T
A
≤
T
MAX
I
MIN
≤
I
R
≤
1mA
T
A
= 25°C
T
MIN
≤
T
A
≤
T
MAX
1mA
≤
I
R
≤
20mA
T
A
= 25°C
T
MIN
≤
T
A
≤
T
MAX
r
Z
Reverse Dynamic Impedance
I
R
= 100µA
T
A
=25°C
T
MIN
≤
T
A
≤
T
MAX
I
R
= 100µA, 10Hz
≤
f
≤
10kHz
I
R
= 100µA, T
A
= 25°C
±
0.1°C
q
ELECTRICAL CHARACTERISTICS
LM185-1.2/LM285-1.2
MIN
TYP
MAX
1.223
1.235
1.247
LM385-1.2/LM385B-1.2
MIN
TYP
MAX
UNITS
V
V
V
ppm/°C
1.205
1.223
20
8
10
1
1.5
10
20
0.2
q
1.235
1.235
20
8
1.260
1.247
∆V
Z
∆Temp
I
MIN
∆V
Z
∆I
R
Average Temperature Coefficient
Minimum Operating Current
Reverse Breakdown Voltage
Change with Current
15
1
1.5
10
25
µA
mV
mV
mV
mV
Ω
Ω
µV
ppm/kHr
q
q
0.6
1.5
0.4
60
20
1.0
1.5
e
n
∆V
Z
∆Time
Wideband Noise (RMS)
Long Term Stability
60
20
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Selected devices with guaranteed maximum temperature
coefficient are available upon request.
Note 3:
For applications requiring low initial tolerance guaranteed over
temperature consult the LT1004 data sheet.
3
LM185-1.2/
LM285-1.2/LM385-1.2
TYPICAL PERFOR A CE CHARACTERISTICS
Reverse Characteristics
100
–55°C TO 125°C
1.2
REVERSE CURRENT (µA)
FORWARD VOLTAGE (V)
10
1
0.1
0
0.2
Temperature Drift
1.245
DYNAMIC IMPEDANCE (Ω)
1.240
10
DYNAMIC IMPEDANCE (Ω)
REVERSE VOLTAGE (V)
1.235
1.230
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
185/285/385 G03
Noise Voltage
700
600
INTEGRATED NOISE (µV
RMS
)
I
R
= 100µA
500
NOISE (nV/√Hz)
400
300
200
100
0
10
R
40
C
30
20
10
0
100
VOLTAGE (V)
100
1k
10k
FREQUENCY (Hz)
4
U W
100k
185/285/385 G06
Foward Characteristics
T
A
= 25°C
0.8
0.4
0.4 0.6 0.8 1.0
REVERSE VOLTAGE (V)
1.2
1.4
0
0.01
1
10
0.1
FORWARD CURRENT (mA)
100
185/285/385 G02
185/285/385 G01
Reverse Dynamic Impedance
100
–55°C TO 125°C
f = 25Hz
10k
Reverse Dynamic Impedance
T
A
= 25°C
I
R
= 100µA
1k
100
10
1
1
0.1
0.01
1
10
0.1
REVERSE CURRENT (mA)
100
185/285/385 G04
0.1
10
100
10k
1k
FREQUENCY (Hz)
100k
1M
185/285/385 G05
Filtered Output Noise
70
60
50
100µA
2.0
I
R
= 100µA
RC LOW PASS
1.5
1.0
0.5
0
5
Response Time
OUTPUT
V
IN
36k
V
OUT
INPUT
0
–5
–100
1k
10k
CUTOFF FREQUENCY (Hz)
100k
185/285/385 G07
0
100
200
300
TIME (µs)
400
500
185/285/385 G08
LM185-1.2/
LM285-1.2/LM385-1.2
SCHE ATIC DIAGRA
W
+
7.5k
Q4
Q12
200k
Q3
20pF
Q1
50k
Q2
Q5
600k
Q10
Q7
20pF
Q11
Q13
300k
Q9
Q6
Q8
Q14
500Ω
60k
W
100k
–
185/285/385 SD
5
Embedded System
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