Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Boost DFN 8

LT8410/LT8410-1

84101fb

APPLICATIONS

Sensor Power

RF Mems Relay Power

General Purpose Bias

TYPICAL APPLICATION

DESCRIPTION

Ultralow Power Boost

Converter with Output

Disconnect

The LT

8410/LT8410-1 are ultralow power boost converters

with integrated power switch, Schottky diode and output

disconnect circuitry. The parts control power delivery by

varying both the peak inductor current and switch off-

time. This control scheme results in low output voltage

ripple as well as high efﬁciency over a wide load range.

The quiescent current is a low 8.5μA, which is further

reduced to 0μA in shutdown. The internal disconnect

circuitry allows the output voltage to be blocked from the

input during shutdown. High value (12.4M/0.4M) resis-

tors are integrated on chip for output voltage detection,

signiﬁcantly reducing input referred quiescent current. The

LT8410/ LT8410-1 also features a comparator built into the

SHDN pin, overvoltage protection for the CAP and V

OUT

pins, built in soft-start and comes in a tiny 8-pin 2mm ×

2mm DFN package.

General Purpose Bias with Wide Input Voltage

FEATURES

Ultralow Quiescent Current

8.5μA in Active Mode

0μA in Shutdown Mode

Comparator Built into SHDN Pin

Low Noise Control Scheme

Adjustable FB Reference Voltage

Wide Input Range: 2.5V to 16V

Wide Output Range: Up to 40V

Integrated Power NPN Switch

25mA Current Limit (LT8410)

8mA Current Limit (LT8410-1)

Integrated Schottky Diode

Integrated Output Disconnect

High Value (12.4M/0.4M) Feedback Resistors

Integrated

Built in Soft-Start (Optional Capacitor from V

REF

to GND)

Overvoltage Protection for CAP and V

OUT

Pins

Tiny 8-Pin 2mm × 2mm DFN Package

SW CAP

GND

CHIP

ENABLE

FBP

8410-1 TA01a

LT8410

2.2µF

0.1µF

100µH

0.1µF

0.1µF*

OUT

= 16V

2.5V to 16V

OUT

REF

SHDN

604k

412k

*HIGHER VALUE CAPACITOR IS REQUIRED

WHEN THE V

IS HIGHER THAN 5V

LOAD CURRENT (mA)

0.01

OUT

PEAK-TO-PEAK RIPPLE (mV)

8410-1 TA02

1010.1

= 3.6V

LOAD CURRENT (mA)

0.01

EFFICIENCY (%)

100

8410-1 TA03

100100.1 1

= 12V

= 5V

= 3.6V

Output Voltage Ripple

vs Load Current

Efﬁciency vs Load Current

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners. Protected by U.S. Patents, including

5481178, 6580258, 6304066, 6127815, 6498466, 6611131.

Summary of content (16 pages)

PAGE 1
LT8410/LT8410-1 Ultralow Power Boost Converter with Output Disconnect DESCRIPTION FEATURES Ultralow Quiescent Current 8.5μA in Active Mode 0μA in Shutdown Mode n Comparator Built into SHDN Pin n Low Noise Control Scheme n Adjustable FB Reference Voltage n Wide Input Range: 2.5V to 16V n Wide Output Range: Up to 40V n Integrated Power NPN Switch 25mA Current Limit (LT8410) 8mA Current Limit (LT8410-1) n Integrated Schottky Diode n Integrated Output Disconnect n High Value (12.4M/0.
PAGE 2
LT8410/LT8410-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VCC Voltage................................................. –0.3V to 16V SW Voltage................................................. –0.3V to 40V CAP Voltage................................................ –0.3V to 40V VOUT Voltage............................................... –0.3V to 40V SHDN Voltage............................................. –0.3V to 16V VREF Voltage............................................... –0.3V to 2.
PAGE 3
LT8410/LT8410-1 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3V, VSHDN = VCC unless otherwise noted.
PAGE 4
LT8410/LT8410-1 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Temperature VCC = 3.6V, VOUT = 16V LOAD = 0.5mA FIGURE 4 CIRCUIT 0.50 0.25 0 – 0.25 – 0.50 8 6 4 2 – 0.75 0 40 80 TEMPERATURE (°C) 0 120 0 4 8410-1 G04 Quiescent Current vs SHDN Voltage 1000 6 4 2 8 12 VCC VOLTAGE (V) 16 0 1 2 3 SHDN VOLTAGE (V) 4 VCC = 3.6V 10 20 30 OUTPUT VOLTAGE (V) 0.5 0 24 120 8410-1 G10 0 4 8 12 SHDN VOLTAGE (V) 8410-1 G09 1.235 13 VCC = 3.
PAGE 5
LT8410/LT8410-1 TYPICAL PERFORMANCE CHARACTERISTICS LT8410 Switching Waveform at 0.5mA Load LT8410 Switching Waveform at No Load VOUT VOLTAGE 2mV/DIV AC COUPLED VOUT VOLTAGE 10mV/DIV AC COUPLED SW VOLTAGE 10V/DIV SW VOLTAGE 10V/DIV INDUCTOR CURRENT 10mA/DIV INDUCTOR CURRENT 20mA/DIV VCC = 3.6V VOUT = 16V 50µs/DIV 2µs/DIV VCC = 3.6V VOUT = 16V 8410-1 G13 LT8410 Switching Waveform at 3mA Load 8410-1 G14 UVLO vs Temperature 2.6 VOUT VOLTAGE 10mV/DIV AC COUPLED UVLO VOLTAGE (V) 2.
PAGE 6
LT8410/LT8410-1 TYPICAL PERFORMANCE CHARACTERISTICS 25 Output Disconnect PMOS Current vs CAP to VOUT Voltage Difference SHDN VOLTAGE 5V/DIV VCAP = 16V LT8410 20 PMOS CURRENT (mA) LT8410 Start-Up Waveforms without Capacitor at VREF Pin INDUCTOR CURRENT 20mA/DIV 15 CAP VOLTAGE 5V/DIV VOUT VOLTAGE 5V/DIV 10 LT8410-1 5 0 VCC = 3.6V VOUT = 16V 0 200µs/DIV 8410-1 G20 4 8 12 16 CAP TO VOUT VOLTAGE DIFFERENCE (V) 8410-1 G19 LT8410 Start-Up Waveforms with 0.
PAGE 7
LT8410/LT8410-1 PIN FUNCTIONS SHDN (Pin 1): Shutdown Pin. This pin is used to enable/ disable the chip. Drive below 0.3V to disable the chip. Drive above 1.45V to activate the chip. Do not float this pin. VREF (Pin 7): Reference Pin. Soft-start can be achieved by placing a capacitor from this pin to GND. This cap will be discharged for 70µs (typical) at the beginning of start-up and then be charged to 1.235V with a 10μA current source. VCC (Pin 2): Input Supply Pin. Must be locally bypassed to GND.
PAGE 8
LT8410/LT8410-1 OPERATION The LT8410 series utilizes a variable peak current, variable off-time control scheme to provide high efficiency over a wide output current range. The operation of the part can be better understood by referring to the Block Diagram. The part senses the output voltage by monitoring the internal FB node, and servoing the FB node voltage to be equal to the FBP pin voltage. The chip integrates an accurate high value resistor divider (12.4M/0.4M) from the VOUT pin.
PAGE 9
LT8410/LT8410-1 APPLICATIONS INFORMATION or 0805 size capacitor will be adequate. A 0.1μF to 1μF capacitor placed on the CAP node is recommended to filter the inductor current, while a 0.1μF to 1μF capacitor placed on the VOUT node will give excellent transient response and stability. To make the VREF pin less sensitive to noise, putting a capacitor on the VREF pin is recommended, but not required. A 47nF to 220nF 0402 capacitor will be sufficient. Table 2 shows a list of several capacitor manufacturers.
PAGE 10
LT8410/LT8410-1 APPLICATIONS INFORMATION Step 4. Calculate the nominal output current: IOUT(NOM) = IIN(AVG) • VIN • 0.7 VOUT mA Step 5. Derate output current: IOUT = IOUT(NOM) • 0.8 For low output voltages the output current capability will be increased. When using output disconnect (load current taken from VOUT), these higher currents will cause the drop in the PMOS switch to be higher resulting in lower output current capability than predicted by the preceding equations.
PAGE 11
LT8410/LT8410-1 APPLICATIONS INFORMATION Board Layout Considerations As with all switching regulators, careful attention must be paid to the PCB layout and component placement. To maximize efficiency, switch rise and fall times are made as short as possible. To prevent electromagnetic interference (EMI) problems, proper layout of the high frequency switching path is essential. The voltage signal of the SW pin has sharp rising and falling edges.
PAGE 12
LT8410/LT8410-1 TYPICAL APPLICATIONS Efficiency vs Load Current L1 100µH C1 2.2µF 100 SW CAP VCC VOUT C2 0.1µF C3 0.1µF LT8410 VREF SHDN TURN ON/OFF 604k GND FBP VIN = 12V 90 VOUT = 16V EFFICIENCY (%) VIN 2.5V to 16V C4 0.1µF VIN = 5V 80 VIN = 3.6V 70 60 412k 50 C1: 2.2μF, 16V, X5R, 0603 8410-1 TA05 C2: 0.1μF, 25V, X5R, 0603 C3: 0.1μF, 25V, X5R, 0603 * C4: 0.1μF, 16V, X7R, 0402 L1: MURATA LQH32CN101K53 * HIGHER CAPACITANCE VALUE IS REQUIRED FOR C3 WHEN THE VIN IS HIGHER THAN 5V 40 0.
PAGE 13
LT8410/LT8410-1 TYPICAL APPLICATIONS 34V Output Converter with Wide Input Voltage Efficiency vs Load Current 90 L1 150µH C1 2.2µF VIN = 12V SW CAP VCC VOUT VOUT = 34V C3 0.1µF LT8410 VREF SHDN TURN ON/OFF C4 0.1µF 133k GND 80 C2 0.1µF FBP EFFICIENCY (%) VIN 2.5V to 16V VIN = 5V 70 VIN = 3.6V 60 50 866k C1: 2.2μF, 16V, X5R, 0603 8410-1 TA09 C2: 0.1μF, 100V, X5R, 0603 C3: 0.1μF, 100V, X5R, 0603 * C4: 0.
PAGE 14
LT8410/LT8410-1 PACKAGE DESCRIPTION DC Package 8-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1719 Rev A) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 0.64 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.45 BSC 1.37 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.05 TYP 2.00 ±0.10 (4 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) R = 0.115 TYP 5 8 0.40 ± 0.10 0.64 ± 0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.
PAGE 15
LT8410/LT8410-1 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 01/11 Corrected Pin Configuration 2 Revised Note 2 in Electrical Characteristics 3 84101fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 16
LT8410/LT8410-1 TYPICAL APPLICATION High Voltage Power Supply Does Not Need a Transformer DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY C3, 0.1µF C5, 0.1µF L1 100µH VIN 2.5V to 16V C1 2.2µF D1 SW VCC C2 0.1µF CAP VOUT 143k C1: 2.2μF, 16V, X5R, 0603 C2 – C7: 0.1μF, 100V, X5R, 0603 C8: 0.1μF, 16V, X7R, 0402 D1 – D4: ON SEMI RB751S40T1G L1: MURATA LQH32CN101K53 GND C4 0.1µF FBP C6 0.1µF C8 0.