Datasheet LX432ISE, LX432ISC, LX432CSC, LX432CLP, LX432ILP Datasheet (Microsemi Corporation)

LX432

A

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

T HE I NFINITE P OWER OF I NNOVATION

DESCRIPTION KEY FEATURES

The LX432 series are low-voltage pre­cision adjustable shunt regulators

with a reference voltage of 1.24V. The
output voltage may be set to any value
between 1.24V and 20V by two external
resistors.

These devices offer low output im-

pedance for improved load regula­tion — typical output impedance is

250mΩ. The LX432 series operates with

an operating current as low as 80µA,
making these devices suitable for por­table and micropower applications.

IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.

Low voltage operation enables the
LX432 to be used in the feedback loop
of isolated low voltage power sup­plies. The minimum output voltage is

determined by the LX432 output voltage
plus the forward voltage drop of the
opto-coupler LED (typically 1.24 + 1.4 =

2.64V minimum). See Figure 10.

The LX432 is offered in 3 and 5-pin
SOT-23 or TO-92 packages, and is a drop­in replacement for the TLV431 and
SC431L devices.

PRODUCT HIGHLIGHT

T YPICAL PROGRAMMABLE VOLTAGE

REFERENCE CIRCUIT

V

IN

P RODUCTION DATA SHEET

■ Low Voltage Operation: 1.24V Reference

■ Initial Voltage Reference Accuracy 1%

■ Adjustable Output Voltage From V

■ Typical Output Dynamic Impedance Less

Than 250mΩ

■ Sink Current Capability 80µA To 20mA

■ Direct Alternative To TLV431

APPLICATIONS

■ Low Voltage Adjustable Power Supplies

■ Instrumentation

■ Computers

■ Portable Equipment

V

K

To 20V

REF

Cathode

LX432

Anode

Reference

R2

GND

PACKAGE ORDER INFORMATION

R1

T

(°C)

A

0 to 70 LX432CSC LX432CSE LX432CLP

-40 to 85 LX432ISC LX432ISE LX432ILP

Plastic SOT-23

SC

3-pin

Note: All surface-mount packages are available in Tape & Reel.

Append the letter "T" to part number. (i.e. LX432CSET)

TO-92 (LP) package also available in ammo-pack.

Plastic SOT-23

SE

5-pin

Plastic TO-92

LP

3-pin

Copyright © 1999
Rev. 1.0 9/99

L INF INITY MICROELECTRONICS INC.

11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: [phone]

1

LX432

PRODUCT DATABOOK 1996/1997

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

ABSOLUTE MAXIMUM RATINGS (Note 1)

Cathode to Anode Voltage (VKA) ................................................................. -0.3V to +20V

Reference Input Current (I
Continuous Cathode Current (I
Operating Junction Temperature

) .................................................................... -50µA to 10µA

REF

) ............................................................. -25mA to 25mA

K

Plastic (SC, SE & LP Packages) ............................................................................. 150°C

Storage Temperature Range ...................................................................... -65°C to 150°C

Lead Temperature ..................................................................................................... 300°C

Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect

to Ground. Currents are positive into, negative out of the specified terminal. Pin
numbers refer to DIL packages only.

THERMAL DATA

SC PACKAGE:

Thermal Resistance - Junction to Ambient,

SE PACKAGE:

Thermal Resistance - Junction to Ambient,

LP PACKAGE:

Thermal Resistance-Junction to Ambient,

Junction Temperature Calculation: TJ = TA + (P
The θ

numbers are guidelines for the thermal performance of the device/pc-board system.

JA

All of the above assume no ambient airflow

θθ

θ

(PC-Mounted) 220°C/W

θθ

JA

(Non-PC Mounted) 410°C/W

θθ

θ

(PC-Mounted) 220°C/W

θθ

JA

(Non-PC Mounted) 410°C/W

θθ

θ

θθ

JA

x θ

).

D

JA

156°C/W

PACKAGE PIN OUTS

2

CATHODE

ANODE

SC PACKAGE — 3-Pin

N.C.

N.C.

CATHODE

SE PACKAGE — 5-Pin

3

1

(Top View)

15

2

34

(Top View)

REF

ANODE

REF

3. CATHODE

2. ANODE

1. REF

Ref (R)

BLOCK DIAGRAM

Cathode (K)

V

REF

Anode (A)

LP PACKAGE

(Top View)

2

Copyright © 1999

Rev. 1.0 9/99

PRODUCT DATABOOK 1996/1997

LX432

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

ELECTRICAL CHARACTERISTICS

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for LX432C with 0°C ≤ TA ≤ 70°C, and the LX432I
with -40°C ≤ TA ≤ 85°C.)

Parameter

Reference Voltage V
Reference Voltage Drift

Ratio Of V

Change In Cathode ∆V

REF

Voltage Change

Reference Terminal Current I

Reference Current Drift (Note 2) ∆I

Minimum Cathode Current For Regulation I
Dynamic Impedance Z
Off-state Cathode Current I

(Note 2) ∆V

(Note 3) ∆V

Symbol

REFIK

REFIK

REFIK

KA

REFIK

REFIK

K (MIN)VKA

KAIK

OFFVKA

Note 2. These parameters are guaranteed by design.

∆V

Note 3. Ratio of change in reference input voltage

REF

∆V

KA

to the change in cathode voltage.

Test Conditions

= 10mA, VKA = V
= 10mA, VKA = V

IK = 10mA, VKA = V

= 10mA, VKA = V

= 10mA, VKA = V
= 10mA, VKA = V

IK = 10mA, VKA = V

= V

, TA = 25°C

REF

= 0.1mA to 15mA, VKA = V

= 16V, TA = 25°C

, TA = 25°C

REF

, 0°C ≤ TA ≤ 70°C

REF

, -40°C ≤ TA ≤ 85°C

REF

to 16V, TA = 25°C

REF

, T

= 25°C, R1=10kΩ, R2 = Open

REF

A

, 0°C ≤ TA ≤ 70°C

REF

, -40°C ≤ TA ≤ 85°C

REF

, TA = 25°C

REF

LX432

Min. Typ. Max.

Units

1.228 1.24 1.252 V
312 mV
420 mV

-1 -2.7 mV/V

0.1 0.5 µA

0.05 0.3 µA

0.1 0.4 µA
55 80 µA

0.2 0.4 Ω

0.004 µA

Copyright © 1999
Rev. 1.0 9/99

3

LX432

PRODUCT DATABOOK 1996/1997

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

GRAPH / CURVE INDEX

Characteristic Curves

FIGURE #

1. Reference Voltage vs. Junction Temperature

2. Reference Current vs. Junction Temperature

3. Cathode Current vs. Cathode Voltage

4. ∆V

5. Dynamic Impedance vs. Junction Temperature

6. Minimum Cathode Current For Regulation vs. Junction

7. Off-State Current vs. Junction Temperature

8. Equivalent Input Noise Voltage vs. Frequency

/ ∆V

REF

KA

Temperature

vs. Junction Temperature

FIGURE INDEX

Parameter Measurement Information

FIGURE #

9. Test Circuit For V

10. Test Circuit For VKA > V

11. Test Circuit For I

= V

KA

REF

REF

OFF

Typical Applications

FIGURE #

12. Flyback With Isolation Using LX431 Or LX431A As Voltage

Reference And Error Amplifier

13. LX432 In 3.3V To 2.7V Low Dropout Regulator Application

4

Copyright © 1999

Rev. 1.0 9/99

PRODUCT DATABOOK 1996/1997

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

CHARACTERISTIC CURVES

LX432

: Reference Voltage (V)

REF

V

1.25

1.245

1.24

1.235

1.23

-40-30-20-100 102030405060708090

TJ : Junction Temperature ( C)

: Reference Current ( A)

REF

I

0.2

0.16

0.12

0.08

0.04

0

-40-30-20-100 102030405060708090

TJ : Junction Temperature ( C)

FIGURE 1 — Reference Voltage vs. Junction Temperature FIGURE 2 — Reference Current vs. Junction Temperature

800
700
600
500
400
300
200
100

: Cathode Current ( A)

K

I

0

-100

-200

-1 -0.5 0 0.5 1 1.5

-1.200

-1.000

-0.800

(mV/V)

KA

V

∆

∆∆

∆

/

-0.600

REF

V

∆

∆∆

∆

-0.400

-0.200

-40-30-20-100 102030405060708090

Copyright © 1999
Rev. 1.0 9/99

TJ : Junction Temperature (V)

TJ : Junction Temperature ( C)

FIGURE 3 — Cathode Current vs. Cathode Voltage FIGURE 4 — ∆V

REF

/ ∆V

vs. Junction Temperature

KA

5

LX432

PRODUCT DATABOOK 1996/1997

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

CHARACTERISTIC CURVES

1.000

0.800

0.600

0.400

0.200

Dynamic Impedance (Ohm)

0.000

-40-30-20-100 102030405060708090

TJ : Junction Temperature ( C)

120

100

80

60

40

20

Minimum Cathode Current ( A)

0

-40-30-20-100 102030405060708090

TJ : Junction Temperature ( C)

FIGURE 5 — Dynamic Impedance vs. Junction Temperature FIGURE 6 — Minimum Cathode Current for Regulation

vs. Junction Temperature

0.012

350

0.010
300

0.008

0.006

0.004

Off-State Current ( A)

0.002

0.000

-40-30-20-100 102030405060708090

TJ : Junction Temperature ( C)

250

200

Noise Voltage (nV/sqrt(Hz))

150

10 100 1K 10K 100K

Frequency (Hz)

FIGURE 7 — Off-State Current vs. Junction Temperature FIGURE 8 — Equivalent Input Noise Voltage vs. Frequency

6

Copyright © 1999

Rev. 1.0 9/99

PRODUCT DATABOOK 1996/1997

A

A

A

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

PARAMETER MEASUREMENT INFORMATION

LX432

Input

V

REF

FIGURE 9 — Test Circuit For VKA = V

I

K

Input

V

K

REF

Input

R

1

I

REF

R

FIGURE 10 — Test Circuit For VKA > V

V

I

OFF

V

2

K

REF

I

K

V

K

REF

Copyright © 1999
Rev. 1.0 9/99

FIGURE 11 — Test Circuit For I

OFF

7

LX432

110/220V AC

PRODUCT DATABOOK 1996/1997

LOW VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS

P RODUCTION DATA SHEET

TYPICAL APPLICATION

V

IN

V

OUT

3.3V

Controller

UC384x/LX155x

FIGURE 12 — LX432 In A Power Supply Isolated Feedback Application

0.1µF

500

DRV

V

CC

I

SENSE

V

GND

FB

12V 3.3V

9

9

140

470µF

LX432

0.1µF

2.7V

(e .g . In te l i7 4 0® chipset)

LX 432

1000µF

9

120

FIGURE 13 — LX432 In 3.3V To 2.7V Low Dropout Regulator Application

PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document
may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of
all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time.

8

0.1µF

Copyright © 1999

Rev. 1.0 9/99