Advanced Monolithic Systems AMS2950 Service Manual

http://www.BDTIC.com/AMS

Advanced AMS2950/AMS2951

Monolithic 150mA LOW DROPOUT VOLTAGE REGULATOR
Systems

RoHS compliant

FEATURES APPLICATIONS

• 5.0V, 3.3V, 3.0V and 2.5V Versions • Battery Powered Systems

• High Accuracy Output Voltage • Portable Consumer Equipment

• Extremely Low Quiescent Current • Cordless Telephones

• Low Dropout Voltage • Portable (Notebook) C omputers

• Extremely Tight Load and Line Regulation • Portable Instrumentation

• Very Low Temperature Coefficient • Radio Control Systems

• Current and Thermal Limiting • Automotive Electronics

• Needs Minimum Capacitance (1µF) for Stability • Avionics

• Unregulated DC Positive Transients 60V • Low-Power Voltage Reference

ADDITIONAL FEATURES (AMS2951 ONLY)

• 1.24V to 29V Programmable Output

• Error Flag Warning of Voltage Output Dropout

• Logic Controlled Electronic Shutdown

GENERAL DESCRIPTION

The AMS2950 and AMS2951 are micropower voltage regulators ideally suited for use in battery-powered systems. These
devices feature very low quiescent current (typ.75µA), and very low dropout voltage (typ.45mV at light loads and 380mV at
150mA) thus prolonging battery life. The quiescent current increases only slightly in dropout. The AMS2950/AMS2951 has
positive transient protection up to 60V and can survive unregulated input transient up to 20V below ground.
The AMS2950 and AMS2951 were designed to include a tigh t initial tolerance (typ. 0.5%), excellent load and line regulation
(typ. 0.05%), and a very low output voltage temperature coefficient, making these devices useful as a low-power voltage
reference

.

The AMS2950 is offered in the 3-pin TO-92 package. AMS2951 is available in 8-pin plastic SOIC and DIP packages and
offers three major additional system features. An error flag output warns of a low output voltage, often due to failing batteries
on input. The AMS2951 also features the logic-compatible shutdown input which enables the regulator to be switched on and
off. The AMS2951 device may be pin-strapped for a 5.0V, 3.3V, 3.0V or 2.5 output, or programmed from 1.24V to 29V with
an external pair of resistors.

ORDERING INFORMATION PIN CONNECTION

PACKAGE TYPE OPERATING

TO-92 8 LEAD PDIP 8 LEAD SOIC

AMS2950ACN-X AMS295 1ACP- AMS2951ACS-X IND.

AMS2950CN-X AMS2951CP-X AMS2951CS-X IND

X = 3.3V, 3.0V, 2.5V

TEMP. RANGE

8L SOIC/ 8L PDIP

OUTPUT

SENSE

SHUTDOWN

GROUND

1
2
3
4

8

INPUT

7

FEEDBACK

6V

TAP

5

ERROR

Top View

TO-92

OUTPUT

INPUT

Advanced Monolithic Systems, Inc.

GND

Bottom View

http://www.BDTIC.com/AMS

AMS2950/AMS2951

ABSOLUTE MAXIMUM RATINGS (Note 1)

Input Supply Voltage -0.3 to +30V
SHUTDOWN Input Voltage, Max. Input Supply Voltage 30V

Error Comparator Output Junction Temperature Range
Voltage,(Note 9) (T
FEEDBACK Input Voltage -1.5 to +30V AMS2950AC-XX,

(Note 9) (Note 10) AMS2951AC-XX,

Power Dissipation Internally Limited
Junction Temperature
Storage Temperature
Soldering Temperature (25 sec)

-65°C to +150°C

+150°C

265°C

ELECTRICAL CHARACTERISTICS at V

Parameter

2.5 V Versions (Note 16)

Output Voltage

Output Voltage

3.0 V Versions (Note 16)
Output Voltage

Output Voltage

3.3 V Versions (Note 16)
Output Voltage

Output Voltage

5.0 V Versions (Note 16)
Output Voltage

Output Voltage

All Voltage Options
Output Voltage

Temperature Coefficient
Line Regulation (Note 14)

Load Regulation (Note 14)

Conditions

(Note 2)

TJ = 25°C (Note 3)

-25°C ≤TJ ≤85°C
Full Operating Temperature

Range
100 µA ≤IL ≤150 mA

TJ ≤T

TJ = 25°C (Note 3)

-25°C ≤TJ ≤85°C
Full Operating Temperature

Range
100 µA ≤IL ≤150 mA

TJ ≤T

TJ = 25°C (Note 3)

-25°C ≤TJ ≤85°C
Full Operating Temperature

Range
100 µA ≤IL ≤150 mA

TJ ≤T

TJ = 25°C (Note 3)

-25°C ≤TJ ≤85°C
Full Operating Temperature

Range
100 µA ≤IL ≤150 mA

TJ ≤T

(Note 12) (Note 4)
6V ≤Vin ≤30V (Note 15)

100 µA ≤IL ≤ 150 mA

JMAX

JMAX

JMAX

JMAX

=Vout+1V, Ta=25°C, unless otherwise noted.

s

2.488

2.475

2.470

2.463

2.985

2.970

2.964

2.958

3.284

3.267

3.260

3.254

4.975

4.95

4.94

4.925

OPERATING RATINGS (Note 1)

) (Note 8)

J

AMS2950C-XX

AMS2951C-XX

AMS2950AC
AMS2951AC

Min. Typ. Max.

2.5

2.5

2.5

2.5

3.0

3.0

3.0

3.0

3.3

3.3

3.3

3.3

5.0

5.0

5.0

5.0

20 50

0.03 0.1 0.04 0.2 %

0.04 0.1 0.1 0.2 %

2.512

2.525

2.530

2.537 2.448

3.015

3.030

3.036

3.042 2.928

3.317

3.333

3.340

3.346 3.221

5.025

5.050

5.06

5.075 4.88

2.475

2.450

2.440

2.970

2.955

2.940

3.267

3.251

3.234

4.925

Min. Typ. Max.

4.95

4.90

-40°C to +125°C

AMS2950C
AMS2951C

2.5

2.5

2.5

2.5

3.0

3.0

3.0

3.0

3.3

3.3

3.3

3.3

5.0

5.0

5.0

5.0

Units

2.525

2.550

2.560

2.562

3.030

3.045

3.060

3.072

3.333

3.350

3.366

3.379

5.05

5.075

5.10

5.12

ppm/°C

V
V
V

V

V
V
V

V

V
V
V

V

V
V
V

V

Advanced Monolithic Systems, Inc.

AMS2950/AMS2951

http://www.BDTIC.com/AMS

ELECTRICAL CHARACTERISTICS (Note 2) (Continued)

A

Units

mV
mV

µA

mA

µV rms
µV rms
µV rms

V

µA

V
V

µA
µA

µA

= TJ =

PARAMETER

Dropout Voltage
(Note 5)

Ground Current

Current Limit

Thermal Regulation (Note 13) 0.05 0.2 0.05 0.2 %/W
Output Noise,

10Hz to 100KHz

8-Pin Versions only

Reference Voltage 1.22 1.235 1.25 1.21 1.235 1.26 V
Reference Voltage Over Temperature (Note 7)

Feedback Pin Bias Current 40 60 40 60 nA

Reference Voltage Temperature
Coefficient

Feedback Pin Bias Current
Temperature Coefficient
Error Comparator

Output Leakage Current

Output Low Voltage

Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis

Shutdown Input
Input logic Voltage

Shutdown Pin Input Current
(Note 3)

Regulator Output Current in
Shutdown (Note 3)

Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the
device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the
Electrical Characteristics tables.
Note 2: Unless otherwise specified all limits guaranteed for V
versions. Limits appearing in boldface type apply over the entire junction temperature range for operation. Limits appearing in normal type apply for T
25°C Additional conditions for the 8-pin versions are FEEDBACK tied to V

Note 3: Guaranteed and 100% production tested.
Note 4: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing AQL levels.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V

differential. At very low values of programmed output voltage, the minimum input supply voltage of 2V ( 2.3V over temperature) must be taken into account.
Note 6: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at
V

= ( V

IN

example, at a programmed output voltage of 5V, the error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds
remain constant as a percent of V
Note 7: V

+1)V. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = Vout/Vref = (R1 + R2)/R2. For

ONOM

≤ (Vin - 1V), 2.3 ≤Vin≤30V, 100µA≤IL≤ 150 mA, TJ ≤ T

ref ≤Vout

CONDITIONS

(Note 2)

IL = 100µ A
IL = 150 mA

IL = 100 µA
IL = 150 mA

V

= 0 160 200 160 200 mA

out

CL = 1µF
CL = 200 µF
CL = 13.3 µF
(Bypass = 0.01 µF pins 7 to

1(AMS2951))

( Note 12 )

V

= 30V

OH

Vin = 4.5V
IOL = 400µA
(Note 6) 40 60 40 60 mV
(Note 6) 75 95 75 95 mV
(Note 6) 15 15 mV

Low (Regulator ON)
High (Regulator OFF)

Vs = 2.4V
Vs = 30V

(Note 11) 3 10 3 10

= ( V

IN

as V

is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.

out

out

+1)V, IL = 100 µA and CL = 1 µF for 5V versions and 2.2µF for 3V and 3.3V

ONOM

TAP

.

JMAX

AMS2950AC
AMS2951AC

Min. Typ. Max.

1.19 1.27 1.185 1.285

0.01 1 0.01 1

2

, OUTPUT tied to SENSE and V

50

380

75

430
160
100

AMS2951AC

20 50 ppm/°C

0.1 0.1 nA/°C

150 250 150 250 mV

1.3

30
450

80

450
120

8

12

430

0.7

50
600

2

30

SHUTDOWN

AMS2950C
AMS2951C

Min. Typ. Max.

75 8 120

≤ 0.8V.

50

380

160
100

AMS2951C

1.3

450

0.7

50
600

80

450

12

Advanced Monolithic Systems, Inc.

AMS2950/AMS2951

http://www.BDTIC.com/AMS

Note 8: The junction-to-ambient thermal resistance are as follows:180°C/W and 160°C/W for the TO-92 (N) package with 0.40 inch and 0.25 inch leads to the
printed circuit board (PCB) respectively, 105°C/W for the molded plastic DIP (P) and 160°C/W for the molded plastic SO-8 (S). The above thermal resistances
for the N, S and P packages apply when the package is soldered directly to the PCB.

Note 9: May exceed input supply voltage.
Note 10: When used in dual-supply systems where the output terminal sees loads returned to a negative supply, the output voltage should be diode-clamped to

ground.

Note 11: V
Note 12: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 13: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line

regulation effects. Specifications are for a 50mA load pulse at V
Note 14: 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 the specification for thermal regulation.
Note 15: Line regulation for the AMS2951 is tested at 150°C for I
See typical performance characteristics for line regulation versus temperature and load current.
Note 16: All AMS2950 devices have the nominal output voltage coded as the last two digits of the part number. In the AMS2951 products, the 2.5V 3.0V and

3.3V versions are designated by the last two digits, but the 5V version is denoted with no code of the part number.

BLOCK DIAGRAM AND TYPICAL APPLICATIONS

UNREGULATED DC

+

≥ 2V, Vin ≤ 30V, V

shutdown

INPUT

+

-

+

1.23V
REFERENCE

=0, Feedback pin tied to 5V

out

.

TAP

=30V (1.25W pulse) for T =10 ms.

IN

= 1 mA. For IL = 100 µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%.

L

AMS2950-XX AMS2951-XX

V

OUT

IL≤

150mA

2

SEE APPLICATION

330k

+

Ω

6

5

4

ERROR
AMPLIFIER

OUTPUT

GROUND

V

OUT

IL≤

+

SEE APPLICATION

150mA

HINTS

UNREGULATED DC

+

FROM
CMOS

OR TTL

FEED­BACK

3

SHUT­DOWN

50mV

+

ERROR DETECTION COMPARATOR

INPUT OUTPUT

+

­ERROR

AMPLIFIER

+

+

-

1.23V
REFERENCE

187

SENSE

V

TAP

ERROR

GROUND

HINTS

TO CMOS
OR TTL

Advanced Monolithic Systems, Inc.

http://www.BDTIC.com/AMS

TYPICAL PERFORMANCE CHARACTERISTICS

AMS2950/AMS2951

Quiescent Current

10

1

0.1

GROUND CURRENT (mA)

0.01

0.1 1 10 150
LOAD CURRENT (mA)

Input Current

270
240
210
180
150

RL= 50

120

90
75
60
45

INPUT CURRENT (mA)

30
15

0

1 23456789100

INPUT VOLTAGE (V)

A)

µ

INPUT CURRENT (

250
225

200
175
150
125
100

75
50

Input Current

5V OUTPUT

RL= 50 k

RL=

Ω

∞

Dropout Characteristics

6

5V OUTPUT

5

4

RL= 50 k

3

2

OUTPUT VOLTAGE (V)

1

Ω

RL= 50

Ω

25

0

1 2 3 4 5 6 1 23456789100

0

INPUT VOLTAGE (V)

0

INPUT VOLTAGE (V)

Temperature Drift of 3
Representative Units

5.06

5V OUTPUT5V OUTPUT 5V OUTPUT

5.04

Ω

5.02

5.0

4.98

OUTPUT VOLTAGE (V)

4.96

4.94

-75 0 25 50 75 100 125

-50 -25

0.2%

150

TEMPERATURE (° C)

Quiescent Current

160
140

A)

µ

120
100

80

IL= 1 mA

IL= 0

60
40
20

QUIESCENT CURRENT (

0

012345678

INPUT VOLTAGE (V)

Quiescent Current

120

A)

µ

110

5V OUTPUT

IL= 100µA

VIN= 6V

100

90

80

70

60

QUIESCENT CURRENT (

50

-75

-50 -25

0 25 50 75 100 125

150

TEMPERATURE (° C)

Advanced Monolithic Systems, Inc.

Quiescent Current

5V OUTPUT

9

8

QUIESCENT CURRENT (mA)

7

-75

-50 -25

0 25 50 75 100 12510150

TEMPERATURE (° C)

VIN= 6V
IL= 150mA

Quiescent Current

8

5V OUTPUT

7

A)

µ

6
5
4

IL= 150mA

3
2
1

QUIESCENT CURRENT (

0

012345678

INPUT VOLTAGE (V)