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LT1962 Series

300mA, Low Noise,

Micropower

LDO Regulators

■

Low Noise: 20µV

RMS

(10Hz to 100kHz)

■

Output Current: 300mA

■

Low Quiescent Current: 30µA

■

Wide Input Voltage Range: 1.8V to 20V

■

Low Dropout Voltage: 270mV

■

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

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Reverse Battery Protection

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No Reverse Current

■

Overcurrent and Overtemperature Protected

■

8-Lead MSOP Package

The LT

1962 series are micropower, low noise, low

dropout regulators. The devices are capable of supplying

300mA of output current with a dropout voltage of 270mV.

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 LT1962 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 LT1962 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 cur-

rent protection. The parts come in fixed output voltages of

1.5V, 1.8V, 2.5V, 3V, 3.3V and 5V, and as an adjustable

device with a 1.22V reference voltage. The LT1962 regu-

lators are available in the 8-lead MSOP package.

3.3V Low Noise Regulator

■

Cellular Phones

■

Battery-Powered Systems

■

Noise-Sensitive Instrumentation Systems

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

LOAD CURRENT (mA)

DROPOUT VOLTAGE (mV)

400

350

300

250

200

150

100

1962 TA02

100

200

30050

150

250

Dropout Voltage

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

SHDN

0.01µF

10µF

1962 TA01

OUT

SENSE

3.7V TO

20V

BYP

GND

LT1962-3.3

3.3V AT 300mA

20µV

RMS

NOISE

1µF

Summary of content (16 pages)

PAGE 1
LT1962 Series 300mA, Low Noise, Micropower LDO Regulators U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Low Noise: 20µVRMS (10Hz to 100kHz) Output Current: 300mA Low Quiescent Current: 30µA Wide Input Voltage Range: 1.8V to 20V Low Dropout Voltage: 270mV 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
LT1962 Series W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) IN Pin Voltage ........................................................ ±20V OUT Pin Voltage .................................................... ±20V Input to Output Differential Voltage (Note 2) ......... ±20V SENSE Pin Voltage ............................................... ±20V ADJ Pin Voltage ...................................................... ±7V BYP Pin Voltage.............................................
PAGE 3
LT1962 Series ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 3) PARAMETER CONDITIONS Load Regulation LT1962-2.5 LT1962-3 LT1962-3.3 LT1962-5 LT1962 (Note 4) MIN VIN = 3.5V, ∆ILOAD = 1mA to 300mA VIN = 3.5V, ∆ILOAD = 1mA to 300mA ● VIN = 4V, ∆ILOAD = 1mA to 300mA VIN = 4V, ∆ILOAD = 1mA to 300mA ● VIN = 4.3V, ∆ILOAD = 1mA to 300mA VIN = 4.
PAGE 4
LT1962 Series ELECTRICAL CHARACTERISTICS Note 5: Operating conditions are limited by maximum junction temperature. The regulated output voltage specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited.
PAGE 5
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS LT1962-2.5 Output Voltage 3.060 IL = 1mA 3.360 IL = 1mA 3.045 3.345 2.52 3.030 3.330 2.51 2.50 2.49 2.48 OUTPUT VOTLAGE (V) 2.53 OUTPUT VOTLAGE (V) OUTPUT VOTLAGE (V) 2.54 LT1962-3.3 Output Voltage LT1962-3 Output Voltage 3.015 3.000 2.985 2.970 2.955 2.47 2.46 – 50 – 25 75 50 25 TEMPERATURE (°C) 100 0 75 50 25 TEMPERATURE (°C) 0 100 LT1962-5 Output Voltage 3.270 125 3.240 – 50 – 25 5.050 1.230 5.025 5.000 4.975 4.
PAGE 6
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS TJ = 25°C RL = ∞ 600 500 400 300 200 VSHDN = 0V 100 600 500 400 300 200 VSHDN = 0V 100 VSHDN = VIN 0 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 750 500 RL = 150Ω IL = 10mA* 250 9 RL = 1.5k IL = 1mA* 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 750 500 RL = 180Ω IL = 10mA* RL = 1.
PAGE 7
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS 1500 8 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V 1250 RL = 24.4Ω IL = 50mA* 1000 750 500 RL = 1.22k IL = 1mA* RL = 122Ω IL = 10mA* 250 0 6 7 RL = 5Ω IL = 300mA* 5 RL = 7.
PAGE 8
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS SHDN Pin Threshold (On-to-Off) IL = 1mA SHDN Pin Input Current 1.4 0.9 0.8 SHDN PIN THRESHOLD (V) SHDN PIN THRESHOLD (V) 0.9 SHDN Pin Threshold (Off-to-On) 1.0 0.7 0.6 0.5 0.4 0.3 0.2 0.1 SHDN PIN INPUT CURRENT (µA) 1.0 0.8 0.7 IL = 300mA 0.6 IL = 1mA 0.5 0.4 0.3 0.2 0.1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 50 25 0 75 TEMPERATURE (°C) 100 1962 G34 1.0 0.8 0.6 0.4 75 50 25 TEMPERATURE (°C) 100 20 15 10 0.6 0.5 0.4 0.3 0.
PAGE 9
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS Input Ripple Rejection Input Ripple Rejection 50 COUT = 10µF 40 30 COUT = 3.3µF 20 CBYP = 0.01µF 70 10 0 100 100k 1k 10k FREQUENCY (Hz) 1M 60 50 CBYP = 100pF 40 30 20 IL = 300mA VIN = VOUT(NOMINAL) + 1V 10 + 50mVRMS RIPPLE COUT = 10µF 0 100 10 1k 10k FREQUENCY (Hz) 100k LOAD REGULATION (mV) MINIMUM INPUT VOLTAGE (V) LT1962 0 1.50 IL = 1mA 1.25 1.00 0.75 0.50 LT1962-1.8 LT1962-1.5 –5 LT1962-3.3 LT1962-3 LT1962-2.
PAGE 10
LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS LT1962-5 10Hz to 100kHz Output Noise (CBYP = 100pF) LT1962-5 10Hz to 100kHz Output Noise (CBYP = 0) VOUT 100µV/DIV LT1962-5 10Hz to 100kHz Output Noise (CBYP = 1000pF) VOUT 100µV/DIV VOUT 100µV/DIV COUT = 10µF IL = 300mA 1ms/DIV COUT = 10µF IL = 300mA 1962 G52 1ms/DIV COUT = 10µF IL = 300mA 1962 G53 LT1962-5 Transient Response COUT = 10µF IL = 300mA 1ms/DIV 1962 G55 OUTPUT VOLTAGE DEVIATION (mV) VIN = 6V 0.4 CIN = 10µF COUT = 10µF 0.
PAGE 11
LT1962 Series U U U PI FU CTIO S 8 IN OUT 1 RP LT1962 + 5 SHDN VIN SENSE + 2 LOAD GND 4 RP 1962 F01 Figure 1. Kelvin Sense Connection pin. The ADJ pin voltage is 1.22V referenced to ground and the output voltage range is 1.22V to 20V. BYP (Pin 3): Bypass. The BYP pin is used to bypass the reference of the LT1962 to achieve low noise performance from the regulator. The BYP pin is clamped internally to ±0.6V (one VBE).
PAGE 12
LT1962 Series U W U U APPLICATIO S I FOR ATIO OUT LT1962 VOUT R2 + ADJ GND R1 1962 F02  R2 VOUT = 1.22V  1 +  + (IADJ )(R2)  R1 VADJ = 1.22V IADJ = 30nA AT 25°C OUTPUT RANGE = 1.22V TO 20V Figure 2. Adjustable Operation plus the ADJ pin bias current. The ADJ pin bias current, 30nA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 2.
PAGE 13
LT1962 Series U W U U APPLICATIO S I FOR ATIO temperature and applied voltage. The most common dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics are good for providing high capacitance in a small package, but exhibit strong voltage and temperature coefficients as shown in Figures 4 and 5. When used with a 5V regulator, a 10µF Y5V capacitor can exhibit an effective value as low as 1µF to 2µF over the operating temperature range.
PAGE 14
LT1962 Series U W U U APPLICATIO S I FOR ATIO For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices. The following table lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 1/16" FR-4 board with one ounce copper. Table 1.
PAGE 15
LT1962 Series U W U U APPLICATIO S I FOR ATIO or a second regulator circuit. The state of the SHDN pin will have no effect on the reverse output current when the output is pulled above the input. 100 REVERSE OUTPUT CURRENT (µA) from the 1.22V reference when the output is forced to 20V. The top resistor of the resistor divider must be chosen to limit the current into the ADJ pin to less than 5mA when the ADJ pin is at 7V.
PAGE 16
LT1962 Series U TYPICAL APPLICATIO S Adjustable Current Source Paralleling of Regulators for Higher Output Current R1 0.1Ω R5 0.1Ω + VIN >2.7V IN C1 10µF R1* 1k OUT R2 40.2k R3 2k LOAD LT1962-2.5 SHDN LT1004-1.2 + R6 2.2k VIN > 3.7V IN + FB C1 10µF C4 0.01µF LT1962-3.3 FB 3.3V 300mA C2 10µF SHDN BYP GND R7 100k GND OUT R2 0.1Ω R4 2.2k IN – OUT C3 0.33µF C5 0.01µF LT1962 BYP *ADJUST R1 FOR 0mA TO 300mA CONSTANT CURRENT 1/2 LT1490 + 1962 TA04 SHDN SHDN ADJ GND R7 1.