Datasheet

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LT1762 Series

Rev B

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TYPICAL APPLICATION

FEATURES DESCRIPTION

150mA, Low Noise, LDO

Micropower Regulators

The LT

1762 series are micropower, low noise, low

dropout regulators. The devices are capable of supply

ing 150mA of output current with a dropout voltage of

270mV. Designed for use in battery-powered systems, the

low 25µA 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 LT1762 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 LT1762 regulators are stable with output

capacitors as low as 2.2µF. 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 cur-

rent protection. The parts come in fixed output voltages

of 2.5V, 3V, 3.3V and 5V, and as an adjustable device

with a 1.22V reference voltage. The LT1762 regulators

are available in the 8-lead MSOP package.

3.3V Low Noise Regulator

APPLICATIONS

Low Noise: 20µV

RMS

(10Hz to 100kHz)

Low Quiescent Current: 25µA

Wide Input Voltage Range: 1.8V to 20V

Output Current: 150mA

Very Low Shutdown Current: < 1µA

Low Dropout Voltage: 270mV

No Protection Diodes Needed

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

Adjustable Output from 1.22V to 20V

Stable with 2.2µF Output Capacitor

Stable with Aluminum, Tantalum or Ceramic

Capacitors

Reverse Battery Protection

No Reverse Current

Overcurrent and Overtemperature Protected

8-Lead MSOP Package

Cellular Phones

Battery-Powered Systems

Frequency Synthesizers

Noise-Sensitive Instrumentation Systems

All registered trademarks and trademarks are the property of their respective owners.

Dropout Voltage

SHDN

0.01μF

10μF

1762 TA01a

OUT

SENSE

3.7V TO

20V

BYP

GND

LT1762-3.3

3.3V AT 150mA

20μV

RMS

NOISE

1μF

OUTPUT CURRENT (mA)

DROPOUT VOLTAGE (mV)

400

350

300

250

200

150

100

80 100 120 140

1762 TA01b

160

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Summary of content (18 pages)

PAGE 1
LT1762 Series 150mA, Low Noise, LDO Micropower Regulators FEATURES DESCRIPTION Low Noise: 20µVRMS (10Hz to 100kHz) nn Low Quiescent Current: 25µA nn Wide Input Voltage Range: 1.8V to 20V nn Output Current: 150mA nn Very Low Shutdown Current: < 1µA nn Low Dropout Voltage: 270mV nn No Protection Diodes Needed nn Fixed Output Voltages: 2.5V, 3V, 3.3V, 5V nn Adjustable Output from 1.22V to 20V nn Stable with 2.
PAGE 2
LT1762 Series ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (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......................................................±0.
PAGE 3
LT1762 Series ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2) PARAMETER CONDITIONS Minimum Operating Voltage ILOAD = 150mA Regulated Output Voltage (Note 4) LT1762-2.5 VIN = 3V, ILOAD = 1mA 3.5V < VIN < 20V, 1mA < ILOAD < 150mA LT1762-3 l VIN = 3.8V, ILOAD = 1mA 4.3V < VIN < 20V, 1mA < ILOAD < 150mA LT1762-5 l VIN = 3.
PAGE 4
LT1762 Series ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2) PARAMETER CONDITIONS MIN Output Voltage Noise COUT = 10µF, CBYP = 0.01µF, ILOAD = 150mA, BW = 10Hz to 100kHz ADJ Pin Bias Current (Notes 3, 8) Shutdown Threshold VOUT = Off to On l VOUT = On to Off l TYP MAX 20 0.25 UNITS µVRMS 30 100 nA 0.8 2 V 0.65 V SHDN Pin Current (Note 9) VSHDN = 0V 0.
PAGE 5
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS Guaranteed Dropout Voltage 450 450 400 400 350 TJ = 125°C 300 250 200 TJ = 25°C 150 100 TJ = 25°C 200 150 100 0 60 80 100 120 140 160 LOAD CURRENT (mA) TJ = 125°C 250 50 40 450 300 0 20 = TEST POINTS 350 50 0 2.54 0 20 2.53 VSHDN = VIN 20 15 10 5 60 80 100 120 140 160 LOAD CURRENT (mA) 0 25 50 75 100 2.51 2.50 2.49 2.48 0 25 50 75 100 3.000 2.985 2.970 2.940 –50 –25 125 3.300 3.285 3.270 3.
PAGE 6
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1762-2.
PAGE 7
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS 800 600 RL = 48.8Ω IL = 25mA* 500 400 RL = 122Ω IL = 10mA* 300 200 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 4.0 3.5 RL = 25Ω IL = 100mA* 2.0 1.5 9 0 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 5.0 8 2.5 RL = 33Ω IL = 100mA* 2.0 1.5 1.0 0 0 1 3 4 5 6 7 INPUT VOLTAGE (V) 2 4.0 3.0 9 RL = 50Ω IL = 100mA* 2.0 1.5 0 10 RL = 100Ω IL = 50mA* SHDN PIN THRESHOLD (V) GND PIN CURRENT (mA) 0.9 3.0 2.5 2.0 1.5 1.0 0.
PAGE 8
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS SHDN Pin Input Current SHDN Pin Input Current 1.6 SHDN PIN INPUT CURRENT (μA) 1.0 0.8 0.6 0.4 0.2 0 1 2 3 4 5 6 7 8 SHDN PIN VOLTAGE (V) 9 120 1.2 1.0 0.8 0.6 0.4 0 –50 –25 10 0 25 50 75 100 Current Limit SHORT-CIRCUIT CURRENT (mA) SHORT-CIRCUIT CURRENT (mA) 300 250 200 150 100 50 VIN = 7V VOUT = 0V 400 350 300 250 200 150 100 0 –50 –25 7 6 20 15 LT1762-2.5/-3/-3.
PAGE 9
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1762 Minimum Input Voltage 2.50 66 2.25 64 62 60 58 56 54 VIN = VOUT (NOMINAL) + 1V + 0.5VP-P RIPPLE AT f = 120Hz IL = 150mA 52 –50 –25 0 VOUT = 1.22V 75 100 IL = 150mA 1.75 1.50 IL = 1mA 1.25 1.00 0.75 0.50 TEMPERATURE (°C) 50 25 0 75 TEMPERATURE (°C) 100 COUT = 10μF IL = 150mA LT1762-3.3 LT1762-5 1 LT1762-2.5 LT1762 LT1762-3 0.1 100k 1k 10k FREQUENCY (Hz) 100 LT1762-3.
PAGE 10
LT1762 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1762-5 10Hz to 100kHz Output Noise CBYP = 0 LT1762-5 10Hz to 100kHz Output Noise CBYP = 100pF VOUT 100μV/DIV VOUT 100μV/DIV 1ms/DIV 1762 G44 1ms/DIV COUT = 10μF IL = 150mA COUT = 10μF IL = 150mA LT1762-5 10Hz to 100kHz Output Noise CBYP = 1000pF LT1762-5 10Hz to 100kHz Output Noise CBYP = 0.01µF VOUT 100μV/DIV VOUT 100μV/DIV 1ms/DIV 1762 G46 1ms/DIV COUT = 10μF IL = 150mA 1762 G47 COUT = 10μF IL = 150mA 0.
PAGE 11
LT1762 Series PIN FUNCTIONS OUT (Pin 1): Output. The output supplies power to the load. A minimum output capacitor of 2.2µF is required to prevent oscillations. Larger output capacitors will be required for applications with large transient loads to limit peak voltage transients. See the Applications Information section for more information on output capacitance and reverse output characteristics. SENSE (Pin 2): Output Sense. For fixed voltage versions of the LT1762 (LT1762-2.5/LT1762-3/LT17623.
PAGE 12
LT1762 Series APPLICATIONS INFORMATION The LT1762 series are 150mA low dropout regulators with micropower quiescent current and shutdown. The devices are capable of supplying 150mA at a dropout voltage of 270mV. Output voltage noise can be lowered to 20µVRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.01µF reference bypass capacitor. Additionally, the reference bypass capacitor will improve transient response of the regulator, lowering the settling time for transient load conditions.
PAGE 13
LT1762 Series APPLICATIONS INFORMATION The LT1762 regulators are designed to be stable with a wide range of output capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. A minimum output capacitor of 2.2µF with an ESR of 3Ω or less is recommended to prevent oscillations. The LT1762-X is a micropower device and output transient response will be a function of output capacitance.
PAGE 14
LT1762 Series APPLICATIONS INFORMATION significant enough to drop capacitor values below appropriate levels. Capacitor DC bias characteristics tend to improve as component case size increases, but expected capacitance at operating voltage should be verified. Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response.
PAGE 15
LT1762 Series APPLICATIONS INFORMATION 0.44W(125°C/W) = 55°C The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 50°C + 55°C = 105°C Protection Features The LT1762 regulators incorporate several protection features which make them ideal for use in battery-powered circuits.
PAGE 16
LT1762 Series PACKAGE DESCRIPTION MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660 Rev G) 0.889 ±0.127 (.035 ±.005) 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 3.00 ±0.102 (.118 ±.004) (NOTE 3) 0.65 (.0256) BSC 0.42 ± 0.038 (.0165 ±.0015) TYP 8 7 6 5 0.52 (.0205) REF RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.006) DETAIL “A” 0° – 6° TYP GAUGE PLANE 0.53 ±0.152 (.021 ±.006) DETAIL “A” 1 2 3 4 1.10 (.043) MAX 0.86 (.
PAGE 17
LT1762 Series REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION B 07/18 Electrical Characteristics table, Load Regulation for the LT1762, second line, Max value changed from 12mV to 15mV. PAGE NUMBER 3 Rev B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use.
PAGE 18
LT1762 Series TYPICAL APPLICATION Paralleling of Regulators for Higher Output Current R1 0.1Ω VIN > 3.7V + IN OUT + FB C1 10μF C4 0.01μF LT1762-3.3 3.3V 300mA C2 10μF SHDN BYP GND R2 0.1Ω IN OUT C5 0.01μF LT1762 BYP SHDN SHDN ADJ GND R3 2.2k R4 2.2k 3 2 R7 1.21k 8 + 1/2 LT1490 – R6 2k R5 10k 1 4 1762 TA02 C3 0.01μF RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Low Dropout Regulator with 20µA IQ Includes 2.