Datasheet LM385PS-1.2, LM385BDR-1-2, LM385D-1-2, LM385LPR-1-2, LM385LP-1-2 Datasheet (Texas Instruments)

LM285-1.2, LM385-1.2, LM385B-1.2

MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

1

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

D

Operating Current Range
– LM285 . . . 10 µA to 20 mA
– LM385 . . . 15 µA to 20 mA
– LM385B ...15 µA to 20 mA

D

1% and 2% Initial Voltage Tolerance

D

Reference Impedance
– LM385...1 Ω Max at 25°C
– All Devices . . . 1.5 Ω Max Over Full

T emperature Range

D

Very Low Power Consumption

D

Applications:
– Portable Meter References
– Portable Test Instruments
– Battery-Operated Systems
– Current-Loop Instrumentation
– Panel Meters

D

Designed to be Interchangeable With
National LM285-1.2 and LM385-1.2

description

These micropower, two-terminal, band-gap voltage references operate over a 10-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.

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.

The LM285-1.2 is characterized for operation from –40°C to 85°C. The LM385-1.2 and LM385B-1.2 are
characterized for operation from 0°C to 70°C.

AVAILABLE OPTIONS

PACKAGED DEVICES

†

T

A

V

Z

TOLERANCE

SMALL OUTLINE

(D)

PLASTIC

(LP)

CHIP FORM

(Y)

°

°

2% LM385D-1.2 LM385LP-1.2

0°C to 70°C

1% LM385BD-1.2 LM385BLP-1.2

LM385Y-1.2

–40°C to 85°C 1% LM285D-1.2 LM285LP-1.2

The D package is available taped and reeled. Add the suffix R to the device type (e.g., LM385DR-1-2).
The chip form is tested at TA = 25°C.

†

For ordering purposes, the decimal point in the part number must be replaced with a hyphen (i.e., show
the -1.2 suffix as “-1-2”).

Copyright  1999, Texas Instruments Incorporated

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.

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.

1
2
3
4

8
7
6
5

NC
NC
NC

ANODE

CATHODE
NC
NC
NC

D PACKAGE

(TOP VIEW)

NC–No internal connection

LP PACKAGE

(TOP VIEW)

ANODE
CATHODE

NC

LM285-1.2, LM385-1.2, LM385B-1.2
MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

symbol

ANODE

CATHODE

schematic

CATHODE

Q13

Q12

Q7

Q4

600 kΩ

7.5 kΩ

ANODE

200 kΩ

50 kΩ

300 kΩ

Q14

20 pF20 pF

Q11

Q10

Q9

Q5

Q3

Q1

Q2

Q8Q6

60 kΩ500 Ω100 kΩ

NOTE A: Component values shown are nominal.

absolute maximum ratings over operating free-air temperature range

†

Reverse current, IR 30 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Forward current, IF 10 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Package thermal impedance, θJA (see Notes 1 and 2): D package 197°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . .

LP package 156°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 T

J(max)

,

θ

JA

, and TA. The maximum allowable power dissipation at any allowable ambient

temperature is PD = (T

J(max)

– TA)/

θ

JA

. Operation at the absolute maximum TJ of 150°C can impact reliability.

2. The package thermal impedance is calculated in accordance with JESD51, except for through-hole packages which use a trace
length of zero.

recommended operating conditions

MIN MAX UNIT

Reference current, I

Z

0.01 20 mA

p

p

LM285-1.2 –40 85

°

Operating free-air temperature range, T

A

LM385-1.2, LM385B-1.2 0 70

°C

LM285-1.2, LM385-1.2, LM385B-1.2

MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

3

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

electrical characteristics at specified free-air temperature

TEST

LM285-1.2 LM385-1.2 LM385B-1.2

PARAMETER

CONDITIONS

T

A

†

MIN TYP MAX MIN TYP MAX MIN TYP MAX

UNIT

V

Z

Reference
voltage

IZ = I(min)
to 20 mA

‡

25°C 1.223 1.235 1.247 1.21 1.235 1.26 1.223 1.235 1.247 V

α

VZ

Average
temperature
coefficient of
reference
voltage

§

IZ = I(min)
to 20 mA

‡

25°C ±20 ±20 ±20 ppm/°C

I

= I(min)

25°C 1 1 1

Change in

reference

Z

()

to 1 mA

‡

Full range 1.5 1.5 1.5

∆V

Z

voltage with

I

= 1 mA

25°C 12 20 20

mV

current

Z

to 20 mA

Full range 30 30 30

∆VZ/∆t

Long-term
change in
reference
voltage

IZ = 100 µA 25°C ±20 ±20 ±20 ppm/khr

IZ(min)

Minimum
reference
current

Full range 8 10 8 15 8 15 µA

Reference I

= 100 µA,

25°C 0.2 0.6 0.4 1 0.4 1

z

z

impedance

Z

µ ,

f = 25 Hz

Full range 1.5 1.5 1.5

Ω

V

n

Broadband
noise voltage

IZ = 100 µA,
f = 10 Hz to
10 kHz

25°C 60 60 60 µV

†

Full range is –40°C to 85°C for the LM285-1.2, and 0°C to 70°C for the LM385-1.2 and LM385B-1.2.

‡

I(min) = 10 µA for the LM285-1.2 and 15 µA for the LM385-1.2 and LM385B-1.2.

§

The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified temperature
range.

electrical characteristics, TA = 25°C

LM385Y-1.2

PARAMETER

TEST CONDITIONS

MIN TYP MAX

UNIT

V

Z

Reference voltage

IZ = 15 µA to 20 mA

1.21 1.235 1.26 V

α

VZ

Average temperature coefficient of reference voltage

§

IZ = 15 µA to 20 mA

±20 ppm/°C

IZ = 15 µA to 1 mA

1

∆VZChange in reference voltage with current

IZ = 1 mA to 20 mA 20

mV

∆VZ/∆t Long-term change in reference voltage IZ = 100 µA ±20 ppm/khr
IZ(min) Minimum reference current 8 15 µA
z

z

Reference impedance IZ = 100 µA 0.4 1 Ω

V

n

Broadband noise voltage

IZ = 100 µA,
f = 10 Hz to 10 kHz

60 µV

§

The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified temperature
range.

LM285-1.2, LM385-1.2, LM385B-1.2
MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

4

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

TYPICAL CHARACTERISTICS

†

Figure 1

0 0.2 0.4 0.6 0.8 1 1.2 1.4

TA = –55°C to 125°C

– Reverse Current –

VR – Reverse Voltage – V

0.1

1

10

100

REVERSE CURRENT

vs

REVERSE VOLTAGE

I

R

Aµ

Figure 2

1010.10.01

–4

0

4

8

12

16

IR – Reverse Current – mA

– Reference Voltage Change – mV

REFERENCE VOLTAGE CHANGE

vs

REVERSE CURRENT

100

∆V

Z

TA = –55°C to 125°C

FORWARD VOLTAGE

vs

FORWARD CURRENT

Figure 3

0.01 0.1 1 10 100

0.8

1.2

0.4

0

IF – Forward Current – mA

– Forward Voltage – VV

F

TA = 25°C

Figure 4

105 125856545255–15–35–55

1.225

1.23

1.235

1.24

1.245

TA – Free-Air Temperature – °C

– Reference Voltage – V

REFERENCE VOLTAGE

vs

FREE-AIR TEMPERATURE

V

Z

1.220

†

Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

LM285-1.2, LM385-1.2, LM385B-1.2

MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

5

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

TYPICAL CHARACTERISTICS

†

Figure 5

REFERENCE IMPEDANCE

vs

REFERENCE CURRENT

IZ – Reference Current – mA

TA = –55°C to 125°C

f = 25 Hz

100

10

1

0.1

1001010.10.01

z

z

– Reference Impedance –

Ω

Figure 6

NOISE VOLTAGE

vs

FREQUENCY

Vn – Noise Voltage – nV/

f – Frequency – Hz

700

600

500

400

300

200

100

0

10 100 1 k 10 k 100 k

√

Hz

IZ = 100 µA
TA = 25°C

V

n

Output Noise Voltage –

f – Cutoff Frequency – kHz

1001010.1

70

60

50

40

30

20

10

0

IZ = 100 µA
TA = 25°C

OUTPUT NOISE VOLTAGE

vs

CUTOFF FREQUENCY

RC Low Pass

µV

C

R

100 µA

Figure 7 Figure 8

Input

V

I

t – Time – µs

Input and Output Voltages – V

0 100 500 600

0

5

0

0.5

1

1.5

V

O

36 kΩ

TRANSIENT RESPONSE

Output

†

Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

LM285-1.2, LM385-1.2, LM385B-1.2
MICROPOWER VOLTAGE REFERENCES

SLVS075C – APRIL 1989 – REVISED JULY 1999

6

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

APPLICATION INFORMATION

+

412 Ω

‡

±1%

†

Adjust for 11.15 mV at 25°C across 953 Ω

‡

Adjust for 12.17 mV at 25°C across 412 Ω

2.00 kΩ ±1%

IO ≈ 58 µA

+

5.1 kΩ

R

LM334

V–

V+

100 kΩ ±1%

10 kΩ

953 Ω

†

±1%

Meter

Type K

LM385-1.2

Mercury Cell

1.345 V
–

–

500 Ω

cw

cw

Figure 9. Thermocouple Cold-Junction Compensator

2.3 V ≤ V+ ≤ 30 V

R

V–

V+

2.74 kΩ

1.2 V

LM385-1.2

LM334

Figure 10. Operation Over a Wide Supply Range

LM385-1.2

1.2 V

499 kΩ

9 V

Figure 11. Reference From a 9-V Battery

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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
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Copyright  1999, Texas Instruments Incorporated