Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
Advanced AMS2931
Monolithic 100mA LOW DROPOUT VOLTAGE REGULATOR
Systems
FEATURES APPLICATIONS
•• 5V and Adjustable Versions Available* •• Battery Powered Systems
•• Output Current in excess of 100mA •• Portable Consumer Equipment
•• Very Low Quiescent Current •• Cordless Telephones
•• Reverse Battery Protection •• Portable (Notebook) Computers
•• Input-output Differential less than 0.6V •• Portable Instrumentation
•• Short Circuit protection •• Radio Control Systems
•• Internal Thermal Overload Protection •• Automotive Electronics
•• 60V Load Dump Protection
•• -50V Reverse Transient Protection
•• Mirror Image Insertion Protection
GENERAL DESCRIPTION
The AMS2931 series consists of positive fixed and adjustable voltage regulators ideally suited for use in battery-powered
systems. These devices feature very low quiescent current of 1mA or less when supplying 10mA loads. This unique
characteristic and the extremely low input -output differential required for proper regulation (0.2V for output currents of
10mA) make the AMS2931 ideal to use for standby power systems.
Originally designed for automotive applications, the AMS2931 and all regulated circuitry are protected from input fault
conditions caused by reverse battery installation or two battery jump starts. During line transients, such as load dump (60V)
when the input voltage to the regulator can momentarily exceed the specified maximum operating voltage, the regulator will
automatically shut down to protect both internal circuits and the load. The AMS2931 series also includes internal current
limiting, thermal shutdown, and is able to withstand temporary power-up with mirror-image insertion.
The AMS2931 is offered in the 3-pin TO-92 package, 8-pin plastic SOIC, TO-220 and TO-263 packages.
ORDERING INFORMATION
OUTPUT PACKAGE TYPE OPER. TEMP
VOLTAGE TO-92 8 LEAD SOIC TO-220 TO-263 RANGE
FIXED* AMS2931AN-X AMS2931AS-X AMS2931AT-X AMS2931AM-X IND
AMS2931N-X AMS2931S-X AMS2931T-X AMS2931M-X IND
ADJ. AMS2931CS IND
X = 5V
*For additional available fixed voltages contact factory
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Voltage Maximum Junction Temperature +125°C
Operating Range 26V Storage Temperature -65°C to +150°C
Overvoltage Protection Lead Temperature (Soldering 10 sec) 230°C
AMS2931A-X, AMS2931C 60V ESD 2000V
AMS2931-X 50V
Internal Power Dissipation (Note 4) Internally Limited
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at VIN =14V, IO =10mA, TJ=25°C, C2 = 100µF unless otherwise specified.
PARAMETER CONDITIONS AMS2931A-X
Min. Typ. Max. AMS2931-X
Min. Typ. Max. Units
5 V Versions
Output Voltage 4.81 5.0 5.19 4.75 5.0 5.25 V
6V ≤VIN ≤26V, IO=100 mA
-40°C ≤TJ ≤125°C4.75 5.25 4.5 5.5 V
Line Regulation 9V ≤VIN ≤ 16V
6V ≤VIN ≤ 26V 2
4
10
30
2
4
10
30
mV
mV
Load Regulation 5mA ≤IO ≤ 100 mA 14 50 14 50 mV
Dropout Voltage IO = 10 mA
IO = 100 mA
0.05
0.3
0.2
0.6
0.05
0.3
0.2
0.6
mV
mV
Quiescent Current IO ≤ 10 mA, 6V ≤ VIN ≤ 26V
-40°C ≤TJ ≤ 125°C
IO = 100 mA, VIN = 14V, TJ = 25°C5
0.4
15
1.0
30
0.4
15
1.0 mA
mA
Output Noise Voltage 10Hz-100kHz, COUT = 100µA500 500 µV rms
Output Impedance 100mADC and 10mArms,100Hz=10kHz 200 200 mΩ
Long Term Stability T =1000hr 20 20 mV
Ripple Rejection fO =120Hz 55 80 80 dB
Maximum Operational Input
Voltage 26 33 26 33 V
Maximum Line Transient RL = 500Ω, VO ≤ 5.5V
T = 1ms, τ ≤100ms
60 70 50 70 V
Reverse Polarity Input Voltage,
D/C -15 -30 -15 -30 V
Reverse Polarity Input Voltage,
Transient RL = 500Ω, T = 1ms, τ ≤100ms -50 -80 -50 -80 V
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at VIN =14V, VOUT =3V IO =10mA, TJ=25°C, R1 =27k, C2 = 100µF unless otherwise specified.
PARAMETER CONDITIONS
(Note 2) Min. AMS2931C
Typ. Max. Units
Adjustable Version
Reference Voltage 1.14 1.20 1.26 V
IO ≤ 100 mA, -40°C ≤TJ ≤ 125°C, R1=27k,
Measured from VOUT to Adjust Pin 1.08 1.32 V
Output Voltage Range 3 24 V
Line Regulation VOUT + 0.6V ≤VIN ≤ 26V .02 1.5 mV/V
Load Regulation 5mA ≤IO ≤ 100 mA 0.3 1%
Dropout Voltage IO ≤ 10 mA
IO = 100 mA 0.05
0.3 0.2
0.6 V
V
Quiescent Current IO = 10 mA
IO = 100 mA
During Shutdown RL = 500Ω
0.4
15
0.8
1
1
mA
mA
mA
Output Noise Voltage 10Hz-100kHz 100 µVrms/V
Output Impedance 100mADC and 10mArms,100Hz=10kHz 40 mΩ
Long Term Stability T =1000hr 0.4 %/1000hr
Ripple Rejection fO = 120Hz 0.02 %/V
Maximum Operational Input
Voltage 26 33 V
Maximum Line Transient IO = 10mA, Reference Voltage ≤ 1.5V
T = 1ms, τ ≤100ms
60 70 V
Reverse Polarity Input Voltage,
D/C RL = 500Ω, VO ≥ -0.3V -15 -30 V
Reverse Polarity Input Voltage,
Transient RL = 500Ω, T = 1ms, τ ≤100ms -50 -80 V
On/Off Threshold Voltage
On
Off
VO = 3V
3.25
2.0
2.2
1.2 V
V
On/Off Threshold Current 20 50 µA
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. For guaranteed performance limits and associated test conditions, see
the Electrical Characteristics tables.
Note 2: See Circuit in Typical Applications. To ensure constant junction temperature, low duty cycle pulse testing is used.
Note 3: Limits appearing in boldface type apply over the entire junction temperature range for operation. Limits appearing in normal type apply for
TA = TJ = 25°C.
Note 4: The junction-to-ambient thermal resistance are as follows: 195°C/W for the TO-92 (N) package, 160°C/W for the molded plastic SO-8 (S), 50°C/W for the
TO-220 package and 73°C/W for the TO-263 package. If the TO-220 package is used with a heat sink, θJA is the sum of the package thermal resistance junction-to-
case of 3°C/W and the thermal resistance added by the heat sink and the thermal interface. The thermal resistance of the TO-263 package can be reduced by
increasing the PCB copper area thermally connected to the package: using 0.5 square inches of copper area, ϕ JA is 50°C/W; with 1 square inch of copper area ϕ JA is
37°C/W; and with 1.6 or more square inches of copper area ϕ JA is 32°C/W.
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
PIN CONNECTIONS
FIXED OUTPUT VOLTAGE
TO-92
Plastic Package (N) 8L SOIC
SO-Package (S) TO-220 (T) TO-263 (M)
OUTPUT INPUT
GND N/C
OUTPUT
N/C
INPUT
GROUND GROUND
GROUND
GROUND
1
2
8
4
3
7
5
6
GND
OUTPUT
INPUT
GND
TAB IS
GND GND
INPUT
OUTPUT
Bottom View Top View Front View Top View
ADJUSTABLE OUTPUT VOLTAGE
8L SOIC
SO-Package (S)
ON/OFF
OUTPUT
ADJ
INPUT
GROUND GROUND
GROUND
GROUND
1
2
8
4
3
7
5
6
Top View
TYPICAL APPLICATIONS
AMS2931-X (Fixed Output) AMS2931C (Adjustable Output)
AMS2931
VIN
UNREGULATED
INPUT
VOUT
REGULATED
OUTPUT
C2**
100µF
C1*
0.1µFGND IQ
*Required if regulator is located far from power supply filter.
**C2 must be at least 100µF to maintain stability; it can be increased
without bound to maintain regulation during transients and it should be
located as close as possible to the regulator. This capacitor must be
rated over the same operating temperature range like the regulator. The
ESR of this capacitor is critical (see curve).
R2
ADJ +
AMS2931
ADJUSTABLE
GND
C2**
100µF
C1*
0.1µF
OUT
OFF
ON
ON/OFF R1
28k
VOUT
VCC
R3
51k
VOUT = VREF × ( R1+R2)/R1
Note: Using 27k for R1 will automatically compensate for errors in
VOUT due to the input bias current of the Adjust Pin ( approx. 1µA)
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
TYPICAL PERFORMANCE CHARACTERISTICS
Line Transient Response
TIME (µs)
OUTPUT VOLTAGE
DEVIATION (mV)
C2= 100 µF
0 15 30 45
0
3
-1
0
1
2
3VIN = VOUT = 9V
6.0
Low Voltage Behavior
2.0
3.0
4.0
5.0
INPUT VOLTAGE (V)
AMS2931-5.0
2.0 3.0 4.0 5.0 6.0
0
IO = 100mA
0 10 20
0
600
400
200
Peak Output Current
30
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
100
500
300
TJ = 85°C
TJ= 25°C
TJ = -40°C
0 40 80
0
0.6
0.4
0.2
Dropout Voltage
120
JUNCTION TEMPERATURE (° C)
INPUT OUTPUT DIFFERENTIAL (V)
0.1
0.5
0.3
IO = 10mA
0 50
0
0.6
0.4
0.2
Dropout Voltage
100
OUTPUT CURRENT (mA)
INPUT OUTPUT DIFFERENTIAL (V)
0.1
0.5
0.3
-40 40 80 120
25
10
QUIESCENT CURRENT (mA)
Quiescent Current
TEMPERATURE (° C)
15
2
0
0
0 30 60
0
30
20
10
Quiescent Current
90
OUTPUT CURRENT (mA)
QUIESCENT CURRENT (mA)
5
25
15
-2
2
6
12
-20 -10 0 10 20 30 40 50 60
INPUT VOLTAGE (V)
Output at Voltage Extremes
OUTPUT VOLTAGE (V)
0
4
10
8
AMS2931-5.0
RL=500Ω
OUTPUT VOLTAGE (V)
-2
INPUT VOLTAGE
CHANGE (V)
~
~
~
~
~
~
-3
~
~
VIN = 14V 20
3
1
Load Transient Response
TIME (µs)
OUTPUT VOLTAGE
DEVIATION (mV)
C2= 100µF
0 15 30 45
0
150
-40
0
40
LOAD CURRENT(mA)
~
~
~
~
IO = 50mA
IO = 100mA
IO = 50mA
IO = 0mA
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
-5
5
20
10
35
-20 -10 0 10 20 30 40 50 60
INPUT VOLTAGE (V)
Quiescent Current
QUIESCENT CURRENT (mA)
0
15
30
25
5V OUTPUT
IO= 10mA
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
0.01
10 Output Impedance
10k 1M
1 100
0.1
1
Operation During Load Dump
TIME (ms)
OUTPUT
VOLTAGE (V)
τ =150ms
-100 0 100 200 300 400 500
-2
0
6
0
10
50
70
CO= 100µF
1.20
1.30 Reference Voltage
1.12
1.14
1.16
1.18
1.22
1.24
1.26
1.28
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
3 6 9 12 15 18 21 240
1.10
~
~
AMS2931C ADJUSTABLE
Maximum Power Dissipation (TO-220)
AMBIENT TEMPERATURE (° C)
0 10 40 60 80
0
12
14
18
22
20
16
10
8
6
4
2
POWER DISSIPATION (W)
NO HEAT SINK
10° C/W HEAT SINK
INPUT
VOLTAGE (V)
45
55
70
60
85
1 10 100 1k 10k 100k 1M
FREQUENCY (Hz)
Ripple Rejection
RIPPLE REJECTION (dB)
50
65
80
75 C2 = 100µF
ALUM
IO= 10mA
45
55
70
60
85
0 25 50 75 100
OUTPUT CURRENT (mA)
Ripple Rejection
RIPPLE REJECTION (dB)
50
65
80
75
5V OUTPUT
FQ= 120Hz
1k10 100k
2
4
~
~
40
30
20
60
20 30 50 70 90 100
0.5
1.0
Maximum Power Dissipation (SO-8)
0.1
0.2
0.3
0.4
0.6
0.7
0.8
0.9
AMBIENT TEMPERATURE (° C)
POWER DISSIPATION (W)
10 20 30 40 50 60 70 80 900
0
0.5
1.0
Maximum Power Dissipation (TO-92)
0.1
0.2
0.3
0.4
0.6
0.7
0.8
0.9
AMBIENT TEMPERATURE (° C)
POWER DISSIPATION (W)
0.125" Lead Lenght
from PC Board
10 20 30 40 50 60 70 800
0
INFINITE HEAT SINK
0.4" Lead
Lenght from
PC Board
RL= 500Ω
AMS2931-5.0
IO = 10mA
AMS2931-5.0
C2 = 100µF
TANTALUM
IO= 50mA
IO= 100mA
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
Maximum Power Dissipation (TO-263)
1
2
3
4
AMBIENT TEMPERATURE (° C)
POWER DISSIPATION (W)
10 20 30 40 50 60 70 80 90 1000
0
θJA = 32° C/W
0.01
0.1
100
0 20 40 60 100
OUTPUT CURRENT (mA)
Output Capacitor ESR
EQUIVALENT SERIES RESISTANCE (Ω)
1
10
VO = 5V
COUT= 100µF
80
3.0
4.0
On/Off Treshold
2.2
2.4
2.6
2.8
3.2
3.4
3.6
3.8
ON/OFF VOLTAGE TRESHOLDS (V)
3 6 9 12 15 18 21 240
2.0
ON
OFF
OUTPUT VOLTAGE (V)
STABLE
REGION
θJA = 37° C/W
θJA = 50° C/W
θJA = 73° C/W
AMS2931C ADJUSTABLE
APPLICATION HINTS
The AMS2931 series require an output capacitor for device
stability. The value required depends on the application circuit
and other factors.
Because high frequency characteristics of electrolytic capacitors
depend greatly on the type and even the manufacturer, the value
of capacitance that works well with AMS2931 for one brand or
type may not necessary be sufficient with an electrolytic of
different origin. Sometimes actual bench testing will be the only
means to determine the proper capacitor type and value. To
obtain stability in all general applications a high quality 100µF
aluminum electrolytic or a 47µF tantalum electrolytic can be
used.
A critical characteristic of the electrolytic capacitors is their
performance over temperature. The AMS2931 is designed to
operate to -40°C, but some electrolytics will freeze around -30°C
therefore becoming ineffective. In such case the result is
oscillation at the regulator output. For all application circuits
where cold operation is necessary, the output capacitor must be
rated to operate at the minimum temperature. In applications
where the regulator junction temperature will never be lower than
25°C the output capacitor value can be reduced by a factor of two
over the value required for the entire temperature range (47µF for
a high quality aluminum or 22µF for a tantalum electrolytic
capacitor).
With higher output currents, the stability of AMS2931 decreases.
Considering the fact that in many applications the AMS2931 is
operated at only a few milliamps (or less) of output current, the
output capacitor value can be reduced even further. For example,
a circuit that is required to deliver a maximum of 10mA of output
current from the regulator output will need an output capacitor of
only half the value compared to the same regulator required to
deliver the full output current of 100mA.
In the case of AMS2931C (adjustable), the minimum value of
output capacitance is a function of the output voltage. As a
general rule, with higher output voltages the value of the output
capacitance decreases, since the internal loop gain is reduced.
In order to determine the minimum value of the output capacitor,
for an application circuit, the entire circuit including the capacitor
should be bench tested at minimum operating temperatures and
maximum operating currents. To maintain internal power
dissipation and die heating to a minimum, the input voltage
should be maintain at 0.6V above the output. Worst-case occurs
just after input power is applied and before the die had the
chance to heat up. After the minimum capacitance value has been
found for the specific brand and type of electrolytic capacitor, the
value should be doubled for actual use to cover for production
variations both in the regulator and the capacitor.
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.
3 LEAD TO-92 PLASTIC PACKAGE (N)
8 LEAD SOIC PLASTIC PACKAGE (S)
0.140±0.010
(3.556±0.127)
0.060±0.010
(1.524±0.254)
0.015±0.002
(0.381±0.051)
0.016±0.003
(0.406±0.076)
0.050±0.005
(1.270±0.127)
0.060±0.005
(1.524±0.127)
DIA
0.180±0.005
(4.572±0.127)
0.180±0.005
(4.572±0.127)
0.050
(1.270)
MAX
0.500
(12.70)
MIN UNCONTROLLED
LEAD DIMENSIONS
10°
NOM
5° NOM
N (TO-92 ) AMS DRW# 042391
0.90
(2.286)
NOM
0°-8° TYP
0.010-0.020
(0.254-0.508)
S (SO-8 ) AMS DRW# 042293
x 45°
0.016-0.050
(0.406-1.270)
0.008-0.010
(0.203-0.254)
0.004-0.010
(0.101-0.254)
0.014-0.019
(0.355-0.483)
0.053-0.069
(1.346-1.752)
0.050
(1.270)
TYP
0.150-0.157**
(3.810-3.988)
0.228-0.244
(5.791-6.197)
0.189-0.197*
(4.801-5.004)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
1 2 3 4
8 7 6 5
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS2931
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).
3 LEAD TO-220 PLASTIC PACKAGE (T)
3 LEAD TO-263 PLASTIC DD (M)
0.330-0.370
0.050
(8.382-9.398)
0.090-0.110
(2.286-2.794) (1.270)
TYP
0.390-0.415
(9.906-10.541) 0.165-0.180
(4.191-4.572) 0.045-0.055
(1.143-1.397)
0.095-0.115
(2.413-2.921)
0.013-0.023
(0.330-0.584)
T (TO-220) AMS DRW# 042193
0.147-0.155
(3.734-3.937)
DIA
0.230-0.270
(5.842-6.858)
0.460-0.500
(11.684-12.700)
0.570-0.620
(14.478-15.748)
0.218-0.252
(5.537-6.401)
0.520-0.570
(13.208-14.478)
0.980-1.070
(24.892-27.178)
0.028-0.038
(0.711-0.965)
0.330-0.370
0.032
0.060
(1.524)
TYP
(8.382-9.398)
(5.05-5.54 )
0.090-0.110
(2.286-2.794)
0.199-0.218
(0.81)
TYP
0.390-0.415
(9.906-10.541)
0.165-0.180
(4.191-4.572) 0.045-0.055
(1.143-1.397)
0.095-0.115
(2.413-2.921)
0.90-0.110
(2.29-2.79)
0.013-0.023
(0.330-0.584)
0.108
(2.74)
TYP
(0.102 )
+0.203
-0.102
0.004 +0.008
-0.004
M (DD3) AMS DRW# 042191R1
