Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - LDO voltage regulator Positive, fixed SOIC 8

LT1763 Series

1763fa

500mA, Low Noise, LDO

Micropower Regulators

■

Low Noise: 20µV

RMS

(10Hz to 100kHz)

■

Output Current: 500mA

■

Low Quiescent Current: 30µA

■

Wide Input Voltage Range: 1.8V to 20V

■

Low Dropout Voltage: 300mV

■

Very Low Shutdown Current: < 1

■

No Protection Diodes Needed

■

Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V

■

Adjustable Output from 1.22V to 20V

■

Stable with 3.3µF Output Capacitor

■

Stable with Aluminum, Tantalum or

Ceramic Capacitors

■

Reverse Battery Protection

■

No Reverse Current

■

Overcurrent and Overtemperature Protected

■

8-Lead SO Package

The LT

1763 series are micropower, low noise, low

dropout regulators. The devices are capable of supplying

500mA of output current with a dropout voltage of 300mV.

Designed for use in battery-powered systems, the low

30µA quiescent current makes them an ideal choice.

Quiescent current is well controlled; it does not rise in

dropout as it does with many other regulators.

A key feature of the LT1763 regulators is low output noise.

With the addition of an external 0.01µF bypass capacitor,

output noise drops to 20µV

RMS

over a 10Hz to 100kHz

bandwidth. The LT1763 regulators are stable with output

capacitors as low as 3.3µF. Small ceramic capacitors can

be used without the series resistance required by other

regulators.

Internal protection circuitry includes reverse battery pro-

tection, current limiting, thermal limiting and reverse

current protection. The parts come in fixed output volt-

ages of 1.5V, 1.8V, 2.5V, 3V, 3.3V and 5V, and as an

adjustable device with a 1.22V reference voltage. The

LT1763 regulators are available in the 8-lead SO package.

Dropout Voltage

3.3V Low Noise Regulator

■

Cellular Phones

■

Battery-Powered Systems

■

Noise-Sensitive Instrumentation Systems

, LTC and LT are registered trademarks of Linear Technology Corporation.

SHDN

0.01µF

10µF

1763 TA01

OUT

SENSE

3.7V TO

20V

BYP

GND

LT1763-3.3

3.3V AT 500mA

20µV

RMS

NOISE

1µF

OUTPUT CURRENT (mA)

DROPOUT VOLTAGE (mV)

400

350

300

250

200

150

100

400

1763 TA02

100

200

300

500

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

Summary of content (17 pages)

PAGE 1
LT1763 Series 500mA, Low Noise, LDO Micropower Regulators U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Low Noise: 20µVRMS (10Hz to 100kHz) Output Current: 500mA Low Quiescent Current: 30µA Wide Input Voltage Range: 1.8V to 20V Low Dropout Voltage: 300mV Very Low Shutdown Current: < 1µA No Protection Diodes Needed Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V Adjustable Output from 1.22V to 20V Stable with 3.
PAGE 2
LT1763 Series U W U W W U W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) IN Pin Voltage ........................................................ ±20V OUT Pin Voltage .................................................... ±20V Input to Output Differential Voltage ....................... ±20V SENSE Pin Voltage ............................................... ±20V ADJ Pin Voltage ...................................................... ±7V BYP Pin Voltage....................................
PAGE 3
LT1763 Series ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2) PARAMETER CONDITIONS Load Regulation LT1763-3 LT1763-3.3 LT1763-5 LT1763 (Note 3) MIN VIN = 4V, ∆ILOAD = 1mA to 500mA VIN = 4V, ∆ILOAD = 1mA to 500mA ● VIN = 4.3V, ∆ILOAD = 1mA to 500mA VIN = 4.3V, ∆ILOAD = 1mA to 500mA ● VIN = 6V, ∆ILOAD = 1mA to 500mA VIN = 6V, ∆ILOAD = 1mA to 500mA ● VIN = 2.
PAGE 4
LT1763 Series ELECTRICAL CHARACTERISTICS Note 6: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage will be equal to: VIN – VDROPOUT. Note 7: GND pin current is tested with VIN = VOUT(NOMINAL) or VIN = 2.3V (whichever is greater) and a current source load. This means the device is tested while operating in its dropout region. This is the worst-case GND pin current.
PAGE 5
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS LT1763-2.5 Output Voltage 3.060 2.54 3.360 IL = 1mA IL = 1mA IL = 1mA 3.045 3.345 2.52 3.030 3.330 2.51 2.50 2.49 2.48 OUTPUT VOLTAGE (V) 2.53 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) LT1763-3.3 Output Voltage LT1763-3 Output Voltage 3.015 3.000 2.985 2.970 2.955 2.47 2.46 –50 –25 0 25 50 75 125 100 2.940 –50 –25 0 25 50 75 125 100 3.285 3.270 3.240 –50 –25 5.050 1.230 5.025 5.000 4.975 4.950 1.220 1.215 1.210 1.205 4.
PAGE 6
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS LT1763-3.3 Quiescent Current 250 40 250 TJ = 25°C RL = ∞ 225 175 150 125 100 75 175 150 125 100 75 50 VSHDN = VIN 25 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 VSHDN = VIN 25 VSHDN = 0V 9 10 1 0 2 3 4 5 6 7 INPUT VOLTAGE (V) 1763 G12 RL = 1.5k IL = 1mA* 0 1 2 8 9 1000 RL = 36Ω IL = 50mA* 800 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.8V 600 RL = 180Ω IL = 10mA* 400 0 10 RL = 1.
PAGE 7
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS LT1763 GND Pin Current 12 10 RL = 24.4Ω IL = 50mA* GND PIN CURRENT (mA) 800 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V 600 RL = 122Ω IL = 10mA* 400 RL = 1.
PAGE 8
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS SHDN Pin Threshold (On-to-Off) SHDN Pin Threshold (Off-to-On) 1.0 IL = 1mA 1.4 0.8 0.7 0.6 0.5 0.4 0.3 0.2 SHDN PIN INPUT CURRENT (µA) 0.9 SHDN PIN THRESHOLD (V) SHDN PIN THRESHOLD (V) 0.9 SHDN Pin Input Current 1.0 0.8 IL = 500mA 0.7 0.6 0.5 IL = 1mA 0.4 0.3 0.2 0.1 0.1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 50 25 0 75 TEMPERATURE (°C) 100 0.8 0.6 0.4 100 80 60 40 100 0.5 0.4 0.3 0 125 Reverse Output Current 0.6 0.4 0.
PAGE 9
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS Input Ripple Rejection Ripple Rejection 68 70 70 CBYP = 0.01µF 66 60 64 60 COUT = 10µF 50 40 30 IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE CBYP = 0 20 10 50 CBYP = 1000pF CBYP = 100pF 40 30 20 IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE COUT = 10µF COUT = 4.7µF 10 0 RIPPLE REJECTION (dB) 80 RIPPLE REJECTION (dB) 58 100k 1k 10k FREQUENCY (Hz) 1M 10 100 100k 1k 10k FREQUENCY (Hz) LT1763-2.
PAGE 10
LT1763 Series U W TYPICAL PERFORMANCE CHARACTERISTICS LT1763-5 10Hz to 100kHz Output Noise CBYP = 0 LT1763-5 10Hz to 100kHz Output Noise CBYP = 100pF LT1763-5 10Hz to 100kHz Output Noise CBYP = 1000pF VOUT 100µV/DIV VOUT 100µV/DIV VOUT 100µV/DIV 1ms/DIV 1ms/DIV 1763 G46 LT1763-5 10Hz to 100kHz Output Noise CBYP = 0.01µF COUT = 10µF IL = 500mA 1763 G47 1763 G45 VIN = 6V CIN = 10µF COUT = 10µF 0.4 0.2 0 –0.2 –0.4 600 400 200 0 0 200 1763 G44 LT1763-5 Transient Response CBYP = 0.
PAGE 11
LT1763 Series U U U PIN FUNCTIONS Note that the voltage drop across the external PC traces will add to the dropout voltage of the regulator. The SENSE pin bias current is 10µA at the nominal rated output voltage. The SENSE pin can be pulled below ground (as in a dual supply system where the regulator load is returned to a negative supply) and still allow the device to start and operate. ADJ (Pin 2): Adjust. For the adjustable LT1763, this is the input to the error amplifier.
PAGE 12
LT1763 Series U U W U APPLICATIONS INFORMATION OUT IN VIN VOUT + R2 LT1763 ADJ GND R1  R2 VOUT = 1.22V  1 +  + (IADJ )(R2)  R1 VADJ = 1.22V IADJ = 30nA AT 25°C OUTPUT RANGE = 1.22V TO 20V 1763 F02 Figure 2. Adjustable Operation The adjustable device is tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.22V. Specifications for output voltages greater than 1.22V will be proportional to the ratio of the desired output voltage to 1.22V: VOUT/1.22V.
PAGE 13
LT1763 Series U U W U APPLICATIONS INFORMATION 20 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF 0 CHANGE IN VALUE (%) X5R –20 –40 –60 Y5V –80 –100 0 2 4 14 8 6 10 12 DC BIAS VOLTAGE (V) 16 1763 F04 Figure 4. Ceramic Capacitor DC Bias Characteristics Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior across temperature and applied voltage.
PAGE 14
LT1763 Series U U W U APPLICATIONS INFORMATION The LT1763 series regulators have internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions, the maximum junction temperature rating of 125°C must not be exceeded. It is important to give careful consideration to all sources of thermal resistance from junction to ambient. Additional heat sources mounted nearby must also be considered.
PAGE 15
LT1763 Series U U W U APPLICATIONS INFORMATION The ADJ pin of the adjustable device can be pulled above or below ground by as much as 7V without damaging the device. If the input is left open circuit or grounded, the ADJ pin will act like an open circuit when pulled below ground and like a large resistor (typically 100k) in series with a diode when pulled above ground.
PAGE 16
LT1763 Series U TYPICAL APPLICATION Paralleling of Regulators for Higher Output Current R1 0.1Ω IN + C1 10µF VIN > 3.8V OUT SENSE LT1763-3.3 + C4 0.01µF SHDN BYP GND 3.3V 1A C2 10µF R2 0.1Ω IN OUT C5 0.01µF LT1763 SHDN R3 2.2k SHDN GND R4 2.2k 3 + BYP ADJ R7 1.21k 8 1/2 LT1490 2 – 4 R6 2k R5 10k 1 C3 0.01µF 1763 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Low Dropout Regulator with 20µA IQ Includes 2.
PAGE 17
This datasheet has been downloaded from: www.DatasheetCatalog.com Datasheets for electronic components.