Datasheet

ManualsBrandsMicrochip ManualsIntegrated Circuits (ICs)Linear voltage regulator 1.2...440 V SOT-89

Supertex inc.

www.supertex.com

Doc.# DSFP-LR8

B080113

LR8

Features

► 13.2 - 450V input voltage range

► Adjustable 1.20 - 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

13.2 - 450V. The output voltage can be adjusted from 1.20 - 440V

provided that the input voltage is at least 12V greater than the

output voltage. The output voltage can be adjusted by means of

two external resistors R1 and R2 as shown in the typical application

circuits. The LR8 regulates the voltage difference between VOUT

and ADJ pins to a nominal value of 1.20V. The 1.20V is amplied

by the external resistor ratio R1 and R2. An internal constant

bias current of typically 10µA is connected to the ADJ pin. This

increases V

OUT

by a constant voltage of 10µA times R2.

The LR8 has current limiting and temperature limiting. The output

current limit is typically 20mA and the minimum temperature limit

is 125°C. An output short circuit current will therefore be limited

to 20mA. When the junction temperature reaches its temperature

limit, the output current and/or output voltage will decrease to

keep the junction temperature from exceeding its temperature

limit. For SMPS start-up circuit applications, the LR8 turns off

when an external voltage greater than the output voltage of the

LR8 is applied to VOUT of the LR8. To maintain stability, a bypass

capacitor of 1.0µF or larger and a minimum DC output current of

500µA are required.

The device is available in TO-243AA (SOT-89), TO-252 (D-PAK),

and TO-92 packages.

Typical Application Circuit

High Input Voltage,

Adjustable 3-Terminal Linear Regulator

LR8

* Required for conditions where V

is less than V

OUT

LOAD

OUT

VOUT

ADJ

VIN

Summary of content (10 pages)

PAGE 1
Supertex inc. LR8 High Input Voltage, Adjustable 3-Terminal Linear Regulator Features ►► ►► ►► ►► ►► ►► General Description 13.2 - 450V input voltage range Adjustable 1.
PAGE 2
LR8 Ordering Information Pin Configuration Part Number Package Options Packing LR8K4-G TO-252 (D-PAK) 2000/Reel LR8N3-G TO-92 1000/Bag LR8N3-G P002 TO-92 2000/Reel LR8N3-G P003 TO-92 2000/Reel LR8N3-G P005 TO-92 2000/Reel LR8N3-G P013 TO-92 2000/Reel LR8N3-G P014 TO-92 2000/Reel LR8N8-G TO-243AA (SOT-89) 2000/Reel VOUT ADJ VIN ADJ TO-252VIN (D-PAK) ADJ VOUT VIN TO-243AA (SOT-89) Absolute Maximum Ratings Parameter Product Marking Value VIN input voltage (voltages ref to A
PAGE 3
LR8 Electrical Characteristics (cont.) (Test conditions unless otherwise specified: -40°C < TA < 85°C.) Sym Parameter Min Typ Max Units Conditions - 0.3 0.5 mA Includes R1 and load current IOUT Minimum output current IADJ Adjust output current 5.0 10 15 µA --- C2 Minimum output load capacitance 1.
PAGE 4
LR8 Typical Application Circuits Figure 1: High Input Voltage, 5.0V Output Linear Regulator * VIN = 17 to 450V VIN VOUT = 5.0V VOUT LR8 R1 6.04kΩ 1% ADJ C1 C2 1.0µF R2 18.2kΩ 1% * Required for conditions where VIN is less than VOUT VOUT = 1.20V 1+ RLOAD ≤16.
PAGE 5
LR8 Typical Performance Curves Temperature Variation 1.30 LR8 1.20 ADJ 12V 1.25 VOUT = 1.2V 2.4kΩ 1.0µF VOUT (V) VIN 1.15 1.10 1.05 1.00 -50 -25 0 25 50 75 100 125 T (junction) (OC) Adjustment Current 12 11 LR8 VOUT = 1.2V 10 ADJ 12V, 200V 400V 2.4kΩ IADJ 1.0ΩF IADJ (µA) VIN VIN = 400V 8 VIN = 200V 7 6 -50 -25 0 LR8 VOUT = 5.0V 25 50 T (junction) (OC) 75 100 125 Load Regulation 5.2 IOUT 5.1 6.04kΩ ±1% ADJ 25V 1.
PAGE 6
LR8 Typical Performance Curves (cont.) VOUT vs. VIN 6 LR8 VOUT = 5.0V 5 6.04kΩ ±1% ADJ 4 1.0µF 0V to 50V VOUT (V) VIN 1kΩ 18.2kΩ ±1% 3 2 1 0 0 10 20 30 40 50 8 10 VIN (V) Ripple Rejection VIN 20VP-P @ 60Hz 65V LR8 IOUT VOUT = 5.0V ADJ Ripple Regection Ratio (dB) -65 6.04kΩ ±1% 1.0µF RLOAD 18.2kΩ ±1% -64 -63 -62 -61 -60 0 2 4 6 IOUT (mA) 30 lCL (mA) 25 20 15 10 -40 -20 0 20 40 60 80 100 Temperature ( C) O Doc.# DSFP-LR8 B080113 6 Supertex inc.
PAGE 7
LR8 Typical Performance Curves (cont.) Load Transient Response VIN LR8 VOUT = 5.0V Closed SW 6.04kΩ ±1% ADJ 1.0µF 25V sw Open 532Ω VOUT 10kΩ 18.2kΩ ±1% Load Transient Response Line Transient Response 400V VIN 0V VIN LR8 VOUT = 5.0V 400V 6.04kΩ ±1% ADJ VIN 1.0µF 10kΩ 18.2kΩ ±1% 0V VOUT 0V Line Transient Response 400V 400V VIN VIN 0V 0V 5.0V 5.0V VOUT 0V VOUT 0V Line Power Down Transient Line Power Up Transient Doc.# DSFP-LR8 B080113 7 Supertex inc. www.supertex.
PAGE 8
LR8 3-Lead TO-252 D-PAK Package Outline (K4) b3 E A c2 E1 4 L3 θ1 D1 H D 1 2 3 L4 L5 Note 1 View B b2 b e Front View Side View Rear View Gauge Plane A1 Seating Plane L2 θ L L1 View B Note: 1. Although 4 terminal locations are shown, only 3 are functional. Lead number 2 was removed. Symbol Dimension (inches) MIN A A1 b b2 b3 c2 D D1 E E1 .086 .000* .025 .030 .195 .018 .235 .205 .250 .170 NOM - - - - - - .240 - - - MAX .094 .005 .035 .045 .215 .
PAGE 9
LR8 3-Lead TO-92 Package Outline (N3) D A Seating Plane 1 2 3 L c b e1 e Side View Front View E1 E 1 3 2 Bottom View Symbol Dimensions (inches) A b c MIN .170 .014 NOM - - MAX .210 .022 † .014 † D E E1 e e1 L .175 .125 .080 .095 .045 .500 - - - - - - .205 .165 .105 .105 .055 .610* † .022 † JEDEC Registration TO-92. * This dimension is not specified in the JEDEC drawing. † This dimension differs from the JEDEC drawing. Drawings not to scale.
PAGE 10
LR8 3-Lead TO-243AA (SOT-89) Package Outline (N8) D D1 C E H L 1 2 E1 3 b b1 e A e1 Top View Symbol Dimensions (mm) Side View A b b1 C D D1 E E1 e MIN 1.40 0.44 0.36 0.35 4.40 1.62 2.29 2.00† NOM - - - - - - - - MAX 1.60 0.56 0.48 0.44 4.60 1.83 2.60 2.29 1.50 BSC e1 3.00 BSC H L 3.94 0.73† - - 4.25 1.20 JEDEC Registration TO-243, Variation AA, Issue C, July 1986. † This dimension differs from the JEDEC drawing Drawings not to scale.