Datasheet LM350T, LM350BT Datasheet (Motorola)

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Order this document by LM350/D

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

The LM350 is an adjustable three–terminal positive voltage regulator
capable of supplying in excess of 3.0 A over an output voltage range of 1.2 V
to 33 V . This voltage regulator is exceptionally easy to use and requires only
two external resistors to set the output voltage. Further, it employs internal
current limiting, thermal shutdown and safe area compensation, making it
essentially blow–out proof.

The LM350 serves a wide variety of applications including local, on card
regulation. This device also makes an especially simple adjustable switching
regulator, a programmable output regulator , or by connecting a fixed resistor
between the adjustment and output, the LM350 can be used as a precision
current regulator.

• Guaranteed 3.0 A Output Current

• Output Adjustable between 1.2 V and 33 V

• Load Regulation Typically 0.1%

• Line Regulation Typically 0.005%/V

• Internal Thermal Overload Protection

• Internal Short Circuit Current Limiting Constant with Temperature

• Output Transistor Safe Area Compensation

• Floating Operation for High Voltage Applications

• Standard 3–lead Transistor Package

• Eliminates Stocking Many Fixed Voltages

THREE–TERMINAL

ADJUSTABLE POSITIVE

VOLTAGE REGULATOR

SEMICONDUCTOR

TECHNICAL DATA

T SUFFIX

PLASTIC PACKAGE

CASE 221A

Pin 1. Adjust

2. V

3. V

1

2

3

Heatsink surface is connected to Pin 2.

out
in

Simplified Application

V

in

Cin*

0.1

µ

F

* = Cin is required if regulator is located an appreciable distance from power supply filter.

** = CO is not needed for stability, however, it does improve transient response.

V

out

Since I

is controlled to less than 100

Adj

this term is negligible in most applications.

MOTOROLA ANALOG IC DEVICE DATA

+

1.25 Vǒ1

I

Adj

LM350

Adjust

)

R

2

R

2

Ǔ

R

1

µ

v

out

R

1

240

+

CO**

µ

1

)

I

AdjR2

A, the error associated with

F

ORDERING INFORMATION

Operating

Device

LM350T
LM350BT# Plastic Power

# Automotive temperature range selections are

available with special test conditions and additional
tests. Contact your local Motorola sales office for
information.

 Motorola, Inc. 1996 Rev 0

Temperature Range

TJ = –40° to +125°C

Package

Plastic PowerTJ = 0° to +125°C

1

LM350

MAXIMUM RATINGS

Rating Symbol Value Unit

Input–Output V oltage Differential VI–V
Power Dissipation P
Operating Junction Temperature Range T
Storage Temperature Range T
Soldering Lead Temperature (10 seconds) T

ELECTRICAL CHARACTERISTICS (V

= 5.0 V; IL = 1.5 A; TJ = T

I–VO

O

D

J

stg

solder

Characteristics

Line Regulation (Note 2)

TA = 25°C, 3.0 V ≤ VI–VO ≤ 35 V

Load Regulation (Note 2)

TA = 25°C, 10 mA ≤ Il ≤ 3.0 A

VO ≤ 5.0 V
VO ≥ 5.0 V

Thermal Regulation, Pulse = 20 ms,

(TA = +25°C)
Adjustment Pin Current 3 I
Adjustment Pin Current Change

3.0 V ≤ VI–VO ≤ 35 V

10 mA ≤ IL ≤ 3.0 A, PD ≤ P

max

Reference Voltage

3.0 V ≤ VI–VO ≤ 35 V

10 mA ≤ IO ≤ 3.0 A, PD ≤ P

max

Line Regulation (Note 2)

3.0 V ≤ VI–VO ≤ 35 V

Load Regulation (Note 2)

10 mA ≤ IL ≤ 3.0 A

VO ≤ 5.0 V
VO ≥ 5.0 V

Temperature Stability (T

low

≤ TJ ≤ T

) 3 T

high

Minimum Load Current to
Maintain Regulation (VI–VO = 35 V)

Maximum Output Current

VI–VO ≤ 10 V, PD ≤ P

VI–VO = 30 V, PD ≤ P
RMS Noise, % of V

TA= 25°C, 10 Hz ≤ f ≤ 10 kHz

max

, TA = 25°C

max

O

Ripple Rejection, VO = 10 V, f = 120 Hz (Note 3)

Without C

C
Long Term Stability, TJ = T

TA= 25°C for Endpoint Measurements

Adj

Adj

= 10 µF

high

(Note 4)

Thermal Resistance, Junction–to–Case

Peak (Note 5)

Average (Note 6)

NOTES: 1. T

to T

low

2.Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately.
Pulse testing with low duty cycle is used.

3.C

Adj

4.Since Long–Term Stability cannot be measured on each device before shipment, this specification is an engineering estimate of average stability
from lot to lot.

5.Thermal Resistance evaluated measuring the hottest temperature on the die using an infrared scanner. This method of evaluation yields very
accurate thermal resistance values which are conservative when compared to the other measurement techniques.

6.The average die temperature is used to derive the value of thermal resistance junction to case (average).

= 0° to +125°C; P

high

, when used, is connected between the adjustment pin and ground.

= 25 W for LM350T; T

max

low

to T

35 Vdc

Internally Limited W

–40 to +125 °C
–65 to +150 °C

300 °C

low

to T

high

; P

[Note 1], unless otherwise noted.)

max

Figure Symbol Min Typ Max Unit

1 Reg

2 Reg

Reg

1,2 ∆I

3 V

1 Reg

2 Reg

3 I

3 I

line

load

therm

Adj

Adj

ref

line

load

S

Lmin

max

– 0.0005 0.03 %/V

–
–

5.0

0.1

0.5

– 0.002 – % VO/W

– 50 100 µA
– 0.2 5.0 µA

1.20 1.25 1.30 V

– 0.02 0.07 %/V

–
–

20

0.3

1.5
– 1.0 – % V
– 3.5 10 mA

3.0

0.25

4.5

1.0

N – 0.003 – % V

4 RR

–

66

65
80

3 S – 0.3 1.0 %/1.0 k

R

= –40° to +125°C; P

high

θJC

max

–
–

= 25 W for LM350BT

2.3
–

1.5

25

70

mV

% V

O

mV

% V

O
O

A
–
–

O

dB
–
–

Hrs.

°C/W

–

2

MOTOROLA ANALOG IC DEVICE DATA

310 310 230 120

125K

135

12.4K3.6K

LM350

Representative Schematic Diagram

5.6K

6.7K

5.0pF

12K

6.8K

510

170
160

200

6.3V

13K

6.3V

V

in

6.3V

190

*

30
pF

5.8K

110

5.1K

Figure 1. Line Regulation and ∆I

V

CC

V

IH

VILV

in

LM350

30
pF

2.4K

12.5K

/Line Test Circuit

Adj

Line Regulation (%/V) =

V

out

I

L

VOH – V

V

OL

OL

x 100

105

4

0.45
V

out

Adjust

V

OH

V

OL

C

0.1µF

in

* Pulse Testing Required:

1% Duty Cycle is suggested.

MOTOROLA ANALOG IC DEVICE DATA

I

Adj

Adjust

R

2

1%

240

R

1

1%

+

1

µ

FC

O

R

L

3

LM350

V

in

C

in

* Pulse Testing Required:

1% Duty Cycle is suggested.

0.1

V

in

µ

F

V

in

Figure 2. Load Regulation and ∆I

Load Regulation (% VO) =

Load Regulation (mV) = VO

LM350

I

Adj

Adjust

R

2

1%

V

VO (min Load) – VO (max Load)

VO (min Load)

(min Load)

out

R

I

L

240

1

1%

C

O

Figure 3. Standard T est Circuit

V

LM350

out

/Load Test Circuit

Adj

–VO

(max Load)

+

1.0

µ

F

I

X 100

L

VO (min Load)

VO

(max Load)

R

L

(max Load)

*

R

L

(min Load)

24V
14V

V

I

0.1

C

in

Pulse Testing Required:
1% Duty Cycle is suggested.

f = 120 Hz

µ

F

C

0.1

in

I

Adj

I

SET

Adjust

R

2

1%

To Calculate R2:
V

= I

out

Assume I

R

1

SET R2

SET

240
1%

+ 1.250 V

= 5.25 mA

V

ref

+

1.0

O

µ

R

L

FC

V

O

Figure 4. Ripple Rejection T est Circuit

V

in

µ

F

LM350

Adjust

V

out

240

R

1

1%

I

L

D1 *
1N4002

C

+

1.0µF

O

V

= 10 V

out

R

L

V

O

+

1.65K

R

2

1%

4

**
C

10

Adj

*D1 Discharges C

**C

provides an AC ground to the adjust pin.

Adj

µ

F

if Output is Shorted to Ground.

Adj

MOTOROLA ANALOG IC DEVICE DATA

LM350

Figure 5. Load Regulation Figure 6. Current Limit

0.4

0.2
0

–0.2
–0.4

Vin = 15 V

–0.6

V

, OUTPUT VOLTAGE CHANGE (%)

out

–0.8

V

∆

–1.0

–75 –50 –25 0 25 50 75 100 125 150

= 10 V

out

TJ, JUNCTION TEMPERATURE (

IL = 1.5 A

IL = 0.5 A

°

C)

Figure 7. Adjustment Pin Current Figure 8. Dropout Voltage

µ

70
65
60
55
50
45

, ADJUSTMENT PIN CURRENT ( A)

40

Adj

I

35

–75 –50 –25 0 25 50 75 100 125 150

TJ, JUNCTION TEMPERATURE (

°

C)

7

TJ = 55°C

, OUTPUT CURRENT (A)
I

, INPUT–OUTPUT VOLTAGE

out

–V

in

V

5

3

out

1
0

3.0

2.5

2.0

DIFFERENTIAL (Vdc)

1.5

1.0

TJ = 25

°

C

°

TJ = 150

010203040

V

–75 –50 –25 0 25 50 75 100 125 150

C

, INPUT VOLTAGE DIFFERENTIAL (Vdc)

in–Vout

∆

V0 = 100 mV

IL = 20 mA

TJ, JUNCTION TEMPERATURE (

IL = 3.0 A

IL = 2.0 A

IL = 500 mA

IL = 200 mA

°

C)

Figure 9. T emperature Stability Figure 10. Minimum Operating Current

1.260

1.250

1.240

1.230

ref

V , REFERENCE VOLTAGE (V)

1.220
–75 –50 –25 0 25 50 75 100 125 150

TJ, JUNCTION TEMPERATURE (

MOTOROLA ANALOG IC DEVICE DATA

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

, QUIESCENT CURRENT (mA)

1.0

B

I

0.5
0

010203040

°

C)

V

, INPUT–OUTPUT VOLTAGE DIFFERENTIAL (Vdc)

in–Vout

TJ = –55°C
TJ = 25

TJ = 150

°

C

°

C

5

LM350

Figure 11. Ripple Rejection versus Output Voltage Figure 12. Ripple Rejection versus Output Current

100

80

60

C

= 10

µ

Adj

F

Without C

Adj

140
120

100

80

C

Adj

= 10 µF

40

20

RR, RIPPLE REJECTION (dB)

0

0 5 10 15 20 25 30 35

Vin – V

= 5 V

out

IL = 500 mA
f = 120 Hz

°

C

TJ = 25

V

out

, OUTPUT VOLTAGE (V)

60

Vin – V

= 5 V

40

RR, RIPPLE REJECTION (dB)

20

0

0.01 0.1 1 10

out

IL = 500 mA
f = 120 Hz

°

C

TJ = 25

I

, OUTPUT CURRENT (A)

out

Figure 13. Ripple Rejection versus Frequency Figure 14. Output Impedance

100

80

60

40

RR, RIPPLE REJECTION (dB)

20

0

10 100 1.0 k 10 k 100 k 1.0 M 10 M

Without C

Adj

f, FREQUENCY (Hz)

IL = 500 mA
Vin = 15 V
V

= 10 V

out

°

C

TJ = 25

C

= 10 µF

Adj

1

10

Vin = 15 V
V

Ω

0

10

–1

10

–2

10

, OUTPUT IMPEDANCE ( )

O

Z

–3

10

10 100 1.0 k 10 k 100 k 1.0 M

= 10 V

out

IL = 500 mA

°

C

TJ = 25

Without C

Adj

f, FREQUENCY (Hz)

Without C

C

= 10 µF

Adj

Adj

1.5

1.0

0.5

, OUTPUT VOL TAGE

DEVIATION (V)

0

out

V

–0.5

∆

–1.0
–1.5

1.0

0.5
0

CHANGE (V)

, INPUT VOLTAGE

in

V

∆

6

Figure 15. Line Transient Response Figure 16. Load Transient Response

3
2
1

CL = 1.0 µF; C

V

= 10 V

out

IL = 50 mA

°

C

TJ = 25

0 10203040

µ

t, TIME (

s)

= 10 µF

Adj

CL = 0; Without C

V

in

Adj

–1

, OUTPUT VOL TAGE

DEVIATION (V)

–2

out

V

–3

∆

1.5

1.0

, LOAD

0.5

L

I

CURRENT (A)

CL = 1.0 µF; C

0

0

010203040

= 10 µF

Adj

CL = 0; Without C

Adj

t, TIME (

Vin = 15 V
V

out

INL = 50 mA
TJ = 25

I

L

µ

s)

MOTOROLA ANALOG IC DEVICE DATA

= 10 V

°

C

LM350

APPLICATIONS INFORMATION

Basic Circuit Operation

The LM350 is a three–terminal floating regulator. In

operation, the LM350 develops and maintains a nominal

1.25 V reference (V

) between its output and adjustment

ref

terminals. This reference voltage is converted to a
programming current (I

) by R1 (see Figure 17), and this

PROG

constant current flows through R2 to ground. The regulated
output voltage is given by:

R

V

= V

out

ref

Since the current from the terminal (I

2

(1 + ) + I

R

1

Adj R2

) represents an

Adj

error term in the equation, the LM350 was designed to control
I

to less than 100 µA and keep it constant. To do this, all

Adj

quiescent operating current is returned to the output terminal.
This imposes the requirement for a minimum load current. If
the load current is less than this minimum, the output voltage
will rise.

Since the LM350 is a floating regulator, it is only the
voltage differential across the circuit which is important to
performance, and operation at high voltages with respect to
ground is possible.

Figure 17. Basic Circuit Configuration

V

in

Adjust

V

= 1.25 V Typical

ref

LM350

I

Adj

V

out

+

R

V

ref

1

I

PROG

R

2

V

out

Load Regulation

The LM350 is capable of providing extremely good load
regulation, but a few precautions are needed to obtain
maximum performance. For best performance, the
programming resistor (R1) should be connected as close to
the regulator as possible to minimize line drops which
effectively appear in series with the reference, thereby
degrading regulation. The ground end of R2 can be returned
near the load ground to provide remote ground sensing and
improve load regulation.

External Capacitors

A 0.1 µF disc or 1 µF tantalum input bypass capacitor (Cin)
is recommended to reduce the sensitivity to input line
impedance.

The adjustment terminal may be bypassed to ground to
improve ripple rejection. This capacitor (C

) prevents ripple

Adj

from being amplified as the output voltage is increased. A
10 µF capacitor should improve ripple rejection about 15 dB
at 120 Hz in a 10 V application.

Although the LM350 is stable with no output capacitance,
like any feedback circuit, certain values of external
capacitance can cause excessive ringing. An output
capacitance (CO) in the form of a 1 µF tantalum or 25 µF
aluminum electrolytic capacitor on the output swamps this
effect and insures stability.

Protection Diodes

When external capacitors are used with any IC regulator, it
is sometimes necessary to add protection diodes to prevent
the capacitors from discharging through low current points
into the regulator.

Figure 18 shows the LM350 with the recommended
protection diodes for output voltages in excess of 25 V or high
capacitance values (CO > 25 µF, C

> 10 µF). Diode D

Adj

prevents CO from discharging thru the IC during an input
short circuit. Diode D2 protects against capacitor C

Adj

discharging through the IC during an output short circuit. The
combination of diodes D1 and D2 prevents C

Adj

from

discharging through the IC during an input short circuit.

Figure 18. V oltage Regulator with

Protection Diodes

D

1

1N4002

V

in

C

in

LM350

Adjust

R

V

out

R

1

2

D

C

Adj

+

2

1N4002

C

O

1

MOTOROLA ANALOG IC DEVICE DATA

7

LM350

Figure 19. “Laboratory” Power Supply with Adjustable Current Limit and Output Voltage

D

6

V

in

32V

Diodes D1 and D2 and transistor Q2 are added to allow adjustment
of output voltage to 0 V.

D6 protects both LM350’s during an input short circuit.

V

in1

µ

F

0.1

Figure 20. Adjustable Current Limiter Figure 21. 5.0 V Electronic Shutdown Regulator

O

SS

V

out

+25V

V

in

* To provide current limiting of I

to the system ground, the source of
the FET must be tied to a negative
voltage below –1.25 V .

V

R2

≤

I

DSS

R1 =

I

Omax

VO < V

(BR)DSS

I

– I

Lmin

As shown O < IO < 1.0 A

Adjust

ref

V

ref

+ I

< IO < 3.0 A

DSS

LM350

DSS
+ 1.25 V + V

LM350

(1)

Adjust 1

R

1

620

R

100

1N4002

V

R

out1

SC

Q

2N3822

I

out

D

1

1N4001
D

2

1N4001

1K

1

–10V

Current

Limit

Adjust

V

out

2

2N5640

VSS*

V

in2

D

1

1N4001

1N4001
D

2

V

240 D

Voltage
Adjust

1N4001

D

3

D

4

1N4001

1N4002

LM350

720

out 2

D

1

IN4001

+

10

Output Range:
0
0

V

out

120

Minimum V

LM350

(2)

Adjust 2

5.0K

Q

2

2N5640

–10V

V

in

Adjust

D1 protects the device during an input short circuit.

5

µ

F

≤

VO ≤25 V

≤

IO ≤1.5 A

+

MPS2222

1.0k

out

I

O

+

1.0

µ

Tantalum

1.0

µ

F

= 1.25 V

V

O

F

TTL
Control

Figure 22. Slow Turn–On Regulator Figure 23. Current Regulator

I

V

in

Adjust

R

LM350

2

V

out

MPS2907

240

50k

1N4001

+

10

µ

F

8

V

in

LM350

Adjust

MOTOROLA ANALOG IC DEVICE DATA

I

Adj

I

+

out

^

10 mA ≤ I

V

out

V

ref

ǒ

R

1

1.25 V
R

1

≤ 3.0 A

out

R

1

Ǔ

)

I

Adj

out

LM350

OUTLINE DIMENSIONS

T SUFFIX

PLASTIC PACKAGE

CASE 221A–06

ISSUE Y

SEATING

–T–

PLANE

B

4

Q

123

F

T

A

U

C

S

H

K

Z

L

V

R

J

G

D

N

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION Z DEFINES A ZONE WHERE ALL
BODY AND LEAD IRREGULARITIES ARE
ALLOWED.

DIM MIN MAX MIN MAX

A 0.570 0.620 14.48 15.75
B 0.380 0.405 9.66 10.28
C 0.160 0.190 4.07 4.82
D 0.025 0.035 0.64 0.88
F 0.142 0.147 3.61 3.73
G 0.095 0.105 2.42 2.66
H 0.110 0.155 2.80 3.93
J 0.018 0.025 0.46 0.64
K 0.500 0.562 12.70 14.27
L 0.045 0.060 1.15 1.52
N 0.190 0.210 4.83 5.33
Q 0.100 0.120 2.54 3.04
R 0.080 0.110 2.04 2.79
S 0.045 0.055 1.15 1.39
T 0.235 0.255 5.97 6.47
U 0.000 0.050 0.00 1.27
V 0.045 ––– 1.15 –––
Z ––– 0.080 ––– 2.04

MILLIMETERSINCHES

MOTOROLA ANALOG IC DEVICE DATA

9

LM350

NOTES

10

MOTOROLA ANALOG IC DEVICE DATA

LM350

NOTES

MOTOROLA ANALOG IC DEVICE DATA

11

LM350

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty , representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation consequential or incidental damages. “T ypical” parameters which may be provided in Motorola
data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”
must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of
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applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury
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arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola
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Opportunity/Affirmative Action Employer.

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12

◊

MOTOROLA ANALOG IC DEVICE DATA

LM350/D

*LM350/D*