Supertex Inc does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate products liability indemnification insurance agreement Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to workmanship No responsibility is assumed for possible omissions or inaccuracies Circuitry and specifications are subject to change without notice For the latest product specifications refer to the Supertex website: http: www supertex com For complete liability information on all Supertex products refer to the most current databook or to the Legal Disclaimer page on the Supertex website

James Adams

Description

Niveau: Secondaire, Lycée, Terminale
1LR8 02/26/04 Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate products liability indemnification insurance agreement. Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the Supertex website: For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website. High Input Voltage Adjustable 3-Terminal Linear Regulator Features ? 12V to 450V input voltage range ? Adjustable 1.20V to 440V output regulation ? 5% output voltage tolerance ? Output current limiting ? 10µA typical ADJ current ? Internal junction temperature limiting Applications ? Off-line SMPS startup circuits ? Adjustable high voltage constant current source ? Industrial Controls ? Motor controls ? Battery chargers ? Power supplies General Description The Supertex LR8 is a high voltage, low output current, adjustable linear regulator. It has a wide operating input voltage range of 12V to 450V. The output voltage can be adjusted from 1.20V to 440V provided that the input voltage is at least 10V greater than the output voltage.

• adjustable


• output current


• vout


• junction temperature


• features ?


• output voltage


• vin


• high input

Sujets

• Première
• Current
• Régulation
• Junction temperature

Informations

• Publié par: profil-zyan-2012
• Nombre de lectures: 31
• Langue: English

Extrait

LR8
LR8
High Input Voltage
Adjustable 3-Terminal Linear Regulator
Features General Description
The Supertex LR8 is a high voltage, low output current, adjustable12V to 450V input voltage range
linear regulator. It has a wide operating input voltage range of
Adjustable 1.20V to 440V output regulation
12V to 450V. The output voltage can be adjusted from 1.20V to
5% output voltage tolerance 440V provided that the input voltage is at least 10V greater than
the output voltage. The output voltage can be adjusted by means
Output current limiting
of two external resistors R1 and R2 as shown in the typical
10?A typical ADJ current application circuits. The LR8 regulates the voltage difference
between V and ADJ pins to a nominal value of 1.20V. TheOUTInternal junction temperature limiting
1.20V is amplified by the external resistor ratio R1 and R2. An
internal constant bias current of typically 10?A is connected to
the ADJ pin. This increases V by a constant voltage of 10?AOUTApplications times R2.
The LR8 has current limiting and temperature limiting. TheOff-line SMPS startup circuits
output current limit is typically 20mA and the minimum temperature
Adjustable high voltage constant current source limit is 125?C. An output short circuit current will therefore be
limited to 20mA. When the junction temperature reaches itsIndustrial Controls
temperature limit, the output current and/or output voltage will
Motor controls
decrease to keep the junction temperature from exceeding its
Battery chargers temperature limit. For SMPS start-up circuit applications, the
LR8 turns off when an external voltage greater than the output
Power supplies
voltage of the LR8 is applied to V of the LR8. To maintainOUT
stability, a bypass capacitor of 1.0?F or larger and a minimum DC
output current of 500?A are required.
The device is available in TO-92, TO-243AA (SOT-89), and
TO-252 (D-PAK) packages.
LR8 Block Diagram and Typical Application
*
VOUT
V VV IN OUTIN
ADJ
R1
LR8
C2
C1 RLOAD
R2
*Required for conditions where V is less than V .IN OUT
02/26/04
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability
indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to
workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the
Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.1
❏❏❏❏❏❏❏❏❏❏❏❏LR8
Ordering Information
Package Options
TO-92 Green TO-92 TO-243AA* Green TO-243AA TO-252 Green TO-252
LR8N3 LR8N3-G LR8N8 LR8N8-G LR8K4 LR8K4-G
* Same as SOT-89. Product supplied on 2000 piece carrier tape reels.
Product marking for TO-243AA:
LR8
where = 2-week alpha date code
Absolute Maximum Ratings Pin Configurations
V Input Voltage -0.5V to +480V*IN 2 (TAB)
TABOutput Voltage Range -0.5V to +470V 1
2
Operating Ambient Temperature Range -40?C to +85?C 13
3Operating Junction Temperature Range -40?C to +125?C TO-243AA
1 2 3 TO-252(SOT-89)Storage Temperature Range -65?C to +150?C TO-92 (D-PAK)
*Voltages referenced to ADJ. V V ADJ
IN OUT
TO-92 1 2 3
TO-243AA 1 2 TAB 3
TO-252 1 2 (TAB) 3
Electrical Characteristics
Test conditions unless otherwise specified: -40?C < T < 85?C.
A
Symbol Parameter Min Typ Max Units Test Conditions
V - V Input to Output Voltage Difference 12 450 VIN OUT
V Overall Output Voltage Regulation 1.14 1.20 1.26 V 12V<V <400V, R1=2.4KΩ, R2=0OUT IN
V 375 400 425 V R1=2.4KΩ, R2=782KΩOUT
∆V Line Regulation 0.003 0.01 %/V 15V<V <400V, V =5V, I =0.5mAOUT IN OUT OUT
∆V Load Regulation 1.4 3.0 % V =15V, V =5V, 0.5mA<I <10mAOUT IN OUT OUT
∆V Temperature Regulation -1 +1 % V =15V, V =5V, I =10mA,OUT IN OUT OUT
-40?C<T <85?CA
I Output Current Limit 10 30 mA T < 85?C, V - V = 10VOUT J IN OUT
I 0.5 mA T > 125?C, V - V = 450VOUT J IN OUT
I Minimum Output Current 0.3 0.5 mA Includes R1 and load currentOUT
I Adjust Output Current 5 10 15 ?AADJ
C2 Minimum Output Load Capacitance 1 ?F
DV /DV Ripple Rejection Ratio 50 60 dB 120Hz, V = 5VOUT IN OUT
T Junction Temperature Limit 125 ?CLIMIT
2
❋❋LR8
Thermal Characteristics
Package Power Dissipation θ θJC JA
@ T =25?C ?C/W ?C/WA
TO-92 0.74W 125 170
†TO-243AA 1.6W 15 78
†TO-252 2.5W 6.25 50
† Mounted on FR4 board, 25mm x 25mm x 1.57mm.
Significant P increase possible on ceramic substrate.D
Functional Block Diagram
LR8V VIN Pass OUT
Element
Overtemp &
1.2V 10µA ADJOvercurrent
3LR8
Typical Application Circuits
*
V =5.0V
OUT
V VV =15V to 450V IN OUTIN
ADJ
R1
6.04KΩ
C2–1%
C1 1.0?F R ≤16.5KΩLOAD
R2
18.2KΩ
–1%
R2V = 1.20V 1+ + I R2ADJOUT R1
Figure 1: High Input Voltage, 5.0V Output Linear Regulator
* Required for conditions where V is less than V .IN OUT
V =15V to 450VIN
+
VAuxiliary
Vout1
-LR8
V V +IN OUT
ADJ
Vout2
Vcc
-
FB PWM IC
Figure 2: SMPS Start-Up Circuit
1.20V
I =LR8 OUT R
V VIN OUT+
ADJ R
V = 15VIN
Load to 450V
1.0 ?F
-
Figure 3: High Voltage Adjustable Constant Current Source
4
LR8
Typical Performance Curves
Temperature Variation
1.30
1.25
V V =1.2V
IN OUT
LR8
1.20
ADJ
1.1512V 2.4KΩ 1.0?F
1.10
1.05
1.00
-50 -25 0 25 50 75 100 125
T(junction) (?C)
Adjustment Current
12
11
V V =1.2V
IN OUT
10LR8
V = 400VIN
V = 12VIN912V, ADJ
200V, 2.4KΩ 1.0?F
400V
8I
ADJ
V = 200VIN
7
6
-50 -25 0 25 50 75 100 125
T(junction) (?C)
Load Regulation
5.2
V V =5.0V IOUTIN OUT
LR8
5.1
ADJ 6.04KΩ
–1%
5.01.0?F25V
RLOAD
18.2KΩ
–1%
4.9
4.8
02468 10
I (mA)OUT
5
V (V) V (V)
OUT OUT
I (?A)
ADJ LR8
Typical Performance Curves V vs. VOUT IN
6
V V =5.0V 5IN OUT
LR8
4
ADJ 6.04KΩ
–1%
1.0?F1KΩ 30V to 50V
18.2KΩ
–1% 2
1
0
010 20304050
V (V)IN
Ripple Rejection
-65
V =5.0VV I -64OUTIN OUT
LR8
ADJ 6.04KΩ -63
20VP-P –1%
@ 60Hz
1.0?F
RLOAD -62
65V 18.2KΩ
–1%
-61
-60
02468 10
I (mA)OUT
Current Limit
30
25
20
15
10
-40 -20 0 20 40 60 80 100
Temperature (°C)
6
lcl (mA)
V (V)
OUT
Ripple Rejection Ratio (dB)LR8LR8
Typical Performance Curves
'(!#

Ω
±
Ω
Ω Ω
±
Load Transient Response

Ω "
±
Ω
Ω
±

Line Transient Response

" "



Line Power Up Transient Line Power Down Transient
02/25/04rev.5
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www.supertex.com7