©2001 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.0
Features
• Limited input voltage and high efficiency.
• Internal thermal over load protection.
• 60V load dump protection.
• Output current up to 0.1A.
Description
LM29 31A is a fixed 3-t ermina l low dropout voltage
regulator designed to need very low quiescent current.
Internally, implemented circuits include 60V load dump
protection, -50V reverse transient short circuit and thermal
over load protection.
TO-92
1: Output 2: GND 3: Input
1
Internal Block Diagram
0.6V MAX DROP
VO
VI
3
2
1
GND
_
+
THERMAL SHUTDOWN
START
OVER VOLTAGE
PROTECTION CURRENT LIMIT
REFERENCE VOLTAGE
PASS ELEME NT
Input Output
LM2931A
Low Dr opout Voltage Regu lator
LM2931A
2
Absolute Maximum Ratings
Electrical Characteristics
(VI =14V, IO =10mA, CO =100µF, TA = 25 oC)
Parameter Symbol Value Unit
Input Voltage Vi 33 V
Over Protection Voltage V(OP) 60 V
Operating Temperature Range TOPR -40~+125 °C
Maximum Junction Temperature TJ150 °C
Storage Temperature Range TSTG -65~+150 °C
Parameter Symbol Conditions Min. Typ. Max. Unit
Output Voltage (I) VO (I) VI = 14V, IO = 10mA 4.81 5.0 5.19 V
Output Voltage (II) VO (II) VI = 6 ~ 26V, IO = 100mA
TJ = -40 ~ +125 oC4.75 5.0 5.25 V
Line Regulation (I) ∆VO (I) VI = 9 ~ 16V, IO = 10mA - 2.0 10 mV
Line Regulation (II) ∆VO (II) VI = 6 ~ 26V, IO = 10mA - 4.0 30 mV
Load Regulation ∆VO (III) VI = 14V, IO = 5 ~ 100mA - 10 50 mV
Output Impedance ZOVI = 14V, IO = 100mA - 100 600 mΩ
Quiescent Current (I) IQ (I) VI = 6 ~ 26V, IO ≤10mA - 0.1 1.0 mA
Quiescent Current (II) IQ (II) VI = 14V, IO≤ 100mA - 5.0 30 mA
Output Noise Voltage VNVI = 14V, IO = 10mA,
f = 10Hz ~ 100KHz - 150 1000 µVrms
Ripple Rejection RR VI = 14V, IO = 10mA, f = 120Hz 55 80 - dB
Dropout Voltage (I) VD (I) IO = 10mA, VD = VI - VO-0.030.2V
Dropout Voltage (II) VD (II) IO = 100mA, VD = VI - VO-0.10.6V
Max Operational Input
Voltage VIN IO = 10mA 26 33 - V
Max Line Transient VLT(MAX) VI = 14V, IO =10mA,
Time =100ms 60 70 - V
Reverse Polarity Input
Voltage DC VI(DC) VI = 14V, IO = 10mA, VO ≥ -0.3V - 15 - 30 - V
Reverse Polarity Input
Voltage Transient VI(TR) VI = 14V, IO = 10mA, Time ≤ 10ms - 50 - 80 - V
Peak Output Current IPK VI = 14V 200 400 600 mA
LM2931A
3
Typical Perfomance Characteristics
Figure 1. Output Voltage vs. Input Voltage
Figure 3. Ripple Rejection vs. Output Voltage
Figure 5. Output Voltage vs. Temperature(Tj)
Figure 2. Quiescent Current vs. Input Voltage
Figure 4. Drop Voltage vs. Output Current
Figure 6. Quiescent Current vs. Temperature(Tj)
FIG.1 Output Voltage
vs. Input Voltage
Input v oltage Vin (V)
6
5
4
3
2
1
7
00 5 10 15
Output voltage Vo(V)
FIG.3 Ripple Rejection
vs. Output Voltage
Output Current (㎃)
90
85
75
65
Ripple Rejection Ratio(㏈)
0 20 40 60 80 100
VIN = 14V
VOUT = 5.0V
f = 120 ㎐
TJ = 25℃
FIG .5 O utput Vol tage
vs. Temperature(Tj)
Temper atur e Tj(℃)
5.04
5.02
5.00
5.06
-25
Outout voltage Vo(V)
75 12502550 100
4.96
4.94
4.92
4.98
FIG.2 Quiescent
vs. Input Voltage
Input voltage Vi n ( V)
10
8.0
6.0
4.0
2.0
0
Quiescent current Iq(mA)
RL= 50 Ω
0 10 20 30 40 50
RL= 500 Ω
Output Current (㎃)
FIG.4 Drop Voltage
vs. Output Current
120
240
200
160
120
0
Dropout voltage Vdrop(㎷)
80
40
80
20 40 60 100
0
VIN = 14V
△VOUT = 100㎷
TJ = 25 ℃
FIG.6 Quiescent Current
vs. Temperature(Tj)
Ju nc ti on temp eratu re T j(℃)
1
0.8
0.6
0.4
0.2
0
Quiescen t current Iq( m A)
75 125
02550 100
-25
LM2931A
4
Typical Application
Figu re 1. Ap pli cation Circ uit
• Ci is required if regulator is located an appreciable distance from power supply filter.
• Co improves stability .
KA76L05
VIVO
Co
0.1µ
µµ
µF
31
2
C I100 µ
µµ
µF
I Q
LM2931A
LM2931A
5
Mechanical Dimensions
Package Dimensions in millimeters
0.46
±0.10
1.27TYP
(R2.29)
3.86MAX
[1.27
±0.20
]1.27TYP
[1.27
±0.20
]
3.60
±0.20
14.47
±0.40
1.02
±0.10
(0.25) 4.58
±0.20
4.58
+0.25
–0.15
0.38
+0.10
–0.05
0.38
+0.10
–0.05
TO-92
LM2931A
6
Ordering Information
Product Number Package Operating Temperature
LM2931AZ5 TO-92 -40°C to + 125°C
LM2931A
7
LM2931A
5/19/01 0.0m 001
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2001 Fairchild Semicond uctor Corporation
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