Bay Linear LM2931Z-90, LM2931Z-85, LM2931Z-33, LM2931Z-15, LM2931Z-10 Datasheet

Bay Linear

Linear Excellence

		100mA Low Dropout Voltage Regulator		LM2931

Description

The Bay Linear LM2931 are low power voltage regulators designed for a wide range of applications. They are an excellent choice for use in Battery Powered applications. The LM2931 feature low quiescent current (100 A Typ.) and low dropout of only 60mV at light loads and 300mV (typ.) at 100mA. The LM2931 has tight initial tolerance of 0.5% typ., extremely good load and line regulation of 0.05% typ. and very low output temperature coefficient.

The Bay Linear LM2931 is available as a fixed voltage regulator and as an adjustable regulator in TO-92 and 8SOIC packages. The Bay Linear LM2931 in an 8SOIC package has an adjustable output voltage from 3V to 24V, programmed with a pair of external resistor. The logic compatible shutdown enables the regulator to be switched ON and OFF.

Features

•Guaranteed 100mA Output

•Fixed Versions 3.3V, 50.V, 8.0

•Very Low Quiescent Current

•Low Dropout Voltage

•Extremely Tight Load and Line Regulation

•Very Low Temperature Coefficient

•Current and Thermal Limiting

•Reverse Battery Protection of –20V

•Transient protection of 60V

•Output programmable from 3V to 24V

Applications

•Battery Powered Systems

•Portable instrumentation

•Notebooks Computers

•Potable Consumer Equipment

•Automotive electronics

•SMPS Post-Regulator

Pin Connection
	TO-92
SOT-89	2
1		3
BAY
LM2931

						OUTPUT	INPUT
INPUT GND OUTPUT							GROUND
	Front View						Bottom View

8SOIC (M)
Output	1	8	Input
GND	2	7	GND
GND	3	6	GND
Feedback	4	5	Shutdown

Ordering Information

Package		Tolerance
SOT-89	LM2931R-XX
TO-92	LM2931Z-XX
8-SOIC	LM2931M-XX
“XX” Voltage Selection Guide
Vout			XX Code
3.3V			33
5.0V			50
8.0V			80
8.5V			85
9.0V			90
10.0V			10
12.0V			12
15.0V			15
Adjustable			Left Blank

Bay Linear, Inc 2478 Armstrong Street, Livermore, CA 94550 Tel: [phone], Fax: [phone]

www.baylinear.com

LM2931

Absolute Maximum Rating

Parameter

Power Dissipation

Internally Limited

Lead Temperature ( Soldering 5 seconds )

260 ° C

Storage Temperature Range

-65 ° C to +150 ° C

Operating Junction Temperature

-55 ° C to +150 ° C

Input Supply Voltage

-20 to +35V

Electrical Characteristics

TJ = 25° C , IO = 100 A, VIN = 14V ( for 2931-15 VIN = 16V), CO = 100 F; unless otherwise specified)

Parameter

Conditions

MIN

TYP

MAX

UNIT

Output Voltage

-25 ° C ≤

Tj ≤

85 ° C

0.985 [ Vo ]

Vo

1.015 [ Vo ]

V

(Fixed Version)

Full Operating Temperature

0.98 [ Vo ]

1.02 [ Vo ]

Output Voltage (Fixed Version)

100µ A ≤

IL ≤

100mA, Tj ≤

T jmax

0.975 [Vo ]

Vo

1.025 [ Vo ]

V

Input Supply Voltage

26

V

Output Voltage Temperature

(Note 1)

50

150

ppm / ° C

Coefficient

Line Regulation (Note 2)

13V ≤

VIN ≤ 26V (Note 3)

0.1

0.4

%

Load Regulation (Note 2)

100µ A ≤

IL ≤

100mA

0.1

0.3

%

Dropout Voltage (Note 4)

IL = 100µ

A

60

200

mV

IL = 100mA

300

600

Ground Current (Note 5)

IL = 100µ

A

100

150

µ A

IL = 10mA

0.9

1.5

mA

IL = 100mA

8

12

mA

Dropout Ground Current

VIN = (VOUT – 0.5V), IL = 100µ A

110

170

µ A

Current Limit

VOUT = 0

160

200

mA

Thermal Regulation (Note 6)

0.05

0.2

% / W

Output Noise,

CL = 2.2µ

F

500

µ Vrms

10Hz to 100KHz

CL = 3.3µ

F

350

IL = 10mA

CL = 33µ

F

120

Ripple Rejection Ratio

IO = 10mA, f = 120Hz, C0 = 100µ F

60

dB

VIN = VO + 3V+2Vpp

8 pin Versions only (LP2951)

Reference Voltage

1.21

1.235

1.26

V

Over Temperature (Note 7)

1.185

1.285

Feedback Pin Bias Current

20

40

η A

Reference Voltage Temperature

(Note 1)

50

ppm/° C

Coefficient

Feedback Pin Bias Current

0.1

η A/° C

Temperature Coefficient

Shutdown Input

Input Logic Voltage

Low (Regulator ON)

1.3

0.7

V

High (Regulator OFF)

2

Shutdown Pin Input Current

VS = 2.4V

30

50

µ A

VS = 26V

450

600

Regulator Output Current

(Note 8)

in Shutdown

5.0V ≤

VOUT ≤

15.0V

10

3.3V ≤

VOUT ≤

5.0V

20

µ A

2.0V ≤

VOUT ≤

3.3V

30

Bay Linear, Inc 2478 Armstrong Street, Livermore, CA 94550

Tel: [phone], Fax: [phone]

www.baylinear.com

LM2931

Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range. Note 2: Unless otherwise specified all limits guaranteed for TJ = 25° C, VIN = VO +1V, IL = 100 A and CL = 1 F. Additional conditions for the 8-

pin versions are feedback tied to –XX Voltage tap and output tied to output Sense pin ( VOUT = XX V) and VSHUTDOWN ≤ 0.8V

Note 2: Regulation is measured at constant junction temperature , using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered under specification for thermal regulation.

Note 3: Line regulation for is tested at 150° C for IL = 1mA. For IL = 100 A and TJ = 125° C, line regulation is guaranteed by design to 0.2%. for B2931-15 16V ≤ VIN ≤ 26V.

Note 4: Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V differential.

Note 5: Ground pin Current is the regulator quiescent current. The total current drawn from the source is the sum of the ground pin current and output load current.

Note 6: Thermal regulation is the change in output voltage at a time T after a change in power dissipation, excluding load or line regulation effects. Specifications are for a 50 mA load pulse (1.25W) for T = 10ms.

Note 7: VREF ≤ VOUT ≤ (VIN –1V), 2.3V ≤ VIN ≤ 26V, 100 A ≤ IL ≤ 100mA, TJ ≤ TJMAX

Note 8: VSHUTDOWN ≥ 2V, VIN ≤ 26V, VOUT = 0

Application Hints

The LM2931 requires an output capacitor for device stability. The value required varies greatly depending upon the application circuit and other factors. The high frequency characteristics of electrolytic capacitors depend greatly on the type and also on the manufacturer. Sometimes only bench testing is the only means to determine the proper capacitor type and value. The high quality 100 F aluminum electrolytic covers all general application circuits, this stability can be obtained with a tantalum electrolytic value of 47 F.

Another critical point of electrolytic characteristics is its performance over temperature. The LM2931 is designed to operate starting at -40° C which may not be true in the case of electrolytic. Higher temperatures generally no problem. The electrolytic. type in aluminum will freeze around -30° C. This could cause an oscillation at output of regulator. At a lower temperature requirement by many applications the capacitor should maintain its performance. So as a result, for an application which regulator junction temperature does not exceed 25° C, the output capacitor can be reduced by the

factor of two over the value needed for the entire temperature range.

Other points with linear regulators are that the twitch higher output current stability decreases. In most applications the LM2931 is operating at few milliamps. In these applications the output capacitance can be further reduced. For example, when the regulator is running at 10mA output current the output capacitance value is half compared to the same regulator that is running at 100 mA.

With the LM2931 adjustable regulator, the minimum value of output capacitance is a function of the output voltage. The value decreases with higher output voltages, since the internal loop gain is reduced.

The worst case occurs at the lower temperature and maximum operating currents, the entire circuit and the electrolytic, should be cooled down to the minimum temperature. The minimum of 0.6 volts required at the input of regulator above the output to keep the power dissipation and die heating to its minimum. After the value for the capacitor has been determined for actual use, the value should be doubled.

Bay Linear, Inc 2478 Armstrong Street, Livermore, CA 94550 Tel: [phone], Fax: [phone]

www.baylinear.com