Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Boost, SEPIC MSOP 8

LT1610

1.7MHz, Single Cell

Micropower

DC/DC Converter

■

Uses Tiny Capacitors and Inductor

■

Internally Compensated

■

Low Quiescent Current: 30

■

Operates with V

as Low as 1V

■

3V at 30mA from a Single Cell

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5V at 200mA from 3.3V

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High Output Voltage Capability: Up to 28V

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Low Shutdown Current: <1µA

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Automatic Burst Mode

Switching at Light Load

■

Low V

CESAT

Switch: 300mV at 300mA

■

8-Lead MSOP and SO Packages

The LT

1610 is a micropower fixed frequency DC/DC

converter that operates from an input voltage as low as 1V.

Intended for small, low power applications, it switches at

1.7MHz, allowing the use of tiny capacitors and inductors.

The device can generate 3V at 30mA from a single cell

(1V) supply. An internal compensation network can be

connected to the LT1610’s V

pin, eliminating two exter-

nal components. No-load quiescent current of the LT1610

is 30µA, and the internal NPN power switch handles a

300mA current with a voltage drop of 300mV.

The LT1610 is available in 8-lead MSOP and SO packages.

Burst Mode is a trademark of Linear Technology Corporation.

Figure 1. 1-Cell to 3V Step-Up Converter

Efficiency

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Pagers

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Cordless Phones

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Battery Backup

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LCD Bias

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Portable Electronic Equipment

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

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

22µF

1 CELL

4.7µH

OUT

30mA

C1, C2: AVX TAJA226M006R

D1: MOTOROLA MBR0520

L1: MURATA LQH1C4R7

1610 F01

681k

PGND

SHDN

GNDCOMP

LT1610

LOAD CURRENT (mA)

0.1

EFFICIENCY (%)

1 10 100

1610 TA01

OUT

= 3V

= 1.5V

= 1V

= 1.25V

Summary of content (16 pages)

PAGE 1
LT1610 1.7MHz, Single Cell Micropower DC/DC Converter U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LT®1610 is a micropower fixed frequency DC/DC converter that operates from an input voltage as low as 1V. Intended for small, low power applications, it switches at 1.7MHz, allowing the use of tiny capacitors and inductors. Uses Tiny Capacitors and Inductor Internally Compensated Low Quiescent Current: 30µA Operates with VIN as Low as 1V 3V at 30mA from a Single Cell 5V at 200mA from 3.
PAGE 2
LT1610 U W W W ABSOLUTE MAXIMUM RATINGS (Note 1) VIN Voltage ................................................................ 8V SW Voltage ............................................... – 0.4V to 30V FB Voltage ..................................................... VIN + 0.3V VC Voltage ................................................................ 2V COMP Voltage .......................................................... 2V Current into FB Pin ..............................................
PAGE 3
LT1610 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. Commercial grade 0°C to 70°C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Switch Current Limit (Note 3) 450 600 900 mA Switch VCESAT ISW = 300mA 300 350 400 mV mV 0.
PAGE 4
LT1610 U W TYPICAL PERFOR A CE CHARACTERISTICS Current Limit (DC = 30%) vs Temperature VCESAT vs Current 600 Current Limit vs Duty Cycle 800 800 500 VCESAT (mV) TA = 85°C 400 TA = 25°C 300 TA = – 40°C 200 100 0 500 200 300 400 SWITCH CURRENT (mA) 100 700 CURRENT LIMIT (mA) SWITCH CURRENT LIMIT (mA) TA = 25°C 700 600 500 400 300 0 25 50 TEMPERATURE (°C) 75 0 1.50 1.25 1.00 0.75 0.50 40 35 1.230 1.225 1.220 1.215 0 6 4 3 5 INPUT VOLTAGE (V) 7 1.210 –50 8 30 25 20 15 10 5 0.
PAGE 5
LT1610 U U U PIN FUNCTIONS VC (Pin 1): Error Amplifier Output. Frequency compensation network must be connected to this pin, either internal (COMP pin) or external series RC to ground. 220kΩ/ 220pF typical value. FB (Pin 2): Feedback Pin. Reference voltage is 1.23V. Connect resistive divider tap here. Minimize trace area at FB. Set VOUT according to VOUT = 1.23V (1 + R1/R2). SHDN (Pin 3): Shutdown. Ground this pin to turn off device. Tie to 1V or more to enable. SW (Pin 5): Switch Pin.
PAGE 6
LT1610 U W U U APPLICATIONS INFORMATION OPERATION The LT1610 combines a current mode, fixed frequency PWM architecture with Burst Mode micropower operation to maintain high efficiency at light loads. Operation can be best understood by referring to the block diagram in Figure 2. Q1 and Q2 form a bandgap reference core whose loop is closed around the output of the converter. When VIN is 1V, the feedback voltage of 1.
PAGE 7
LT1610 U U W U APPLICATIONS INFORMATION A SEPIC (Single-Ended Primary Inductance Converter) schematic is shown in Figure 4. This converter topology produces a regulated output over an input voltage range that spans (i.e., can be higher or lower than) the output. Recommended component placement for a SEPIC is shown in Figure 5. C3 1µF CERAMIC L1 22µH INPUT Li-ION 3V to 4.2V 6 VIN + 1 C1 22µF 6.3V 5 SW VC FB 1M COMP • + 604k SHDN GND PGND 7 4 VOUT 3.
PAGE 8
LT1610 U W U U APPLICATIONS INFORMATION COMPONENT SELECTION Inductors Inductors used with the LT1610 should have a saturation current rating (–30% of zero current inductance) of approximately 0.5A or greater. DCR should be 0.5Ω or less. The value of the inductor should be matched to the power requirements and operating voltages of the application. In most cases a value of 4.7µH or 10µH is suitable.
PAGE 9
LT1610 U U W U APPLICATIONS INFORMATION L1 22µH • 6 VIN + 4 CELLS C1 22µF 6.3V C4 1µF CERAMIC 1 C3 1µF CERAMIC 5 SW VC 1M FB COMP 324k SHDN GND PGND 7 4 C1, C2: ALUMINUM ELECTROLYTIC C3 TO C5: CERAMIC X7R OR X5R D1: MBR0520 L1, L2: MURATA LQH3C220 OR SUMIDA CLS62-220 3 VOUT 5V 120mA • L2 22µH 2 LT1610 8 D1 + C2 22µF 6.3V C5 1µF CERAMIC 1610 F06 SHUTDOWN Figure 6. 4-Cell Alkaline to 5V/120mA SEPIC DC/DC Converter sation network is modified to achieve stable operation.
PAGE 10
LT1610 U U W U APPLICATIONS INFORMATION output capacitor because it introduces a zero in the regulator’s loop gain. This zero may not be effective because the ceramic capacitor’s ESR is very low. Most current mode switching regulators (including the LT1610) can easily be compensated without this zero. Any design should be tested for stability at the extremes of operating temperatures; this is particularly so of circuits that use ceramic output capacitors. Figure 9 details a 2.5V to 5V boost converter.
PAGE 11
LT1610 U TYPICAL APPLICATIONS 2-Cell to 5V Converter 6 VIN 3 + 2 CELLS C1 15µF 90 D1 VOUT 5V 50mA 5 SW 1M 2 FB SHDN LT1610 8 324k COMP VC PGND 1 4 + 7 GND C2 15µF VIN = 3V VIN = 2V 80 EFFICIENCY (%) L1 4.7µH Efficiency VIN = 1.5V 70 60 50 C1, C2: AVX TAJA156M010R D1: MOTOROLA MBR0520 L1: SUMIDA CD43-4R7 MURATA LQH1C4R7 0.
PAGE 12
LT1610 U TYPICAL APPLICATIONS 5V to 9V/150mA Boost Converter VIN 5V 1 + C1 15µF 6 5 VIN SW FB VC COMP SHDN GND PGND 7 4 VOUT 9V 150mA 2 3 R3 158k 85 80 R2 1M LT1610 8 90 D1 + C2 15µF EFFICIENCY (%) L1 10µH Efficiency 75 70 65 60 55 50 C1: AVX TAJA156M010 C2: AVX TAJB156M016 D1: MOTOROLA MBR0520 L1: MURATA LQH3C100M24 1 1610 TA08 SHUTDOWN 300 1610 TA09 5V to 9V Boost Converter Transient Response VOUT 200mV/DIV LOAD CURRENT 140mA 10mA INDUCTOR CURRENT 200mA/DIV 200µs/D
PAGE 13
LT1610 U TYPICAL APPLICATIONS 3.3V TO 8V/70mA, – 8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors D2 VOFF – 8V 5mA 1µF D3 0.22µF 0.22µF 0.22µF: 1µF: 4.7µF: D1: D2, D3, D4: L1: TAIYO YUDEN EMK212BJ224MG TAIYO YUDEN LMK212BJ105MG TAIYO YUDEN LMK316BJ475ML MOTOROLA MBRO520 BAT54S SUMIDA CDRH5D185R4 D4 0.22µF L1 5.4µH VIN 3.3V 1µF D1 6 3 1µF AVDD 8V 70mA 5 VIN SW COMP SHDN 8 274k C1 4.7µF C2 4.7µF LT1610 1 100k VON 24V 5mA FB VC GND PGND 7 4 2 48.
PAGE 14
LT1610 U TYPICAL APPLICATIONS Single Cell Super Cap Charger L1 4.7µH 6 CHARGE 3 + C1 15µF SHUTDOWN 1 AA ALKALINE SW VIN COMP SHDN 15k VC FB GND PGND 7 4 VOUT 4.5V R1 200k 5 Q1 8 + LT1610 1 R4 20Ω D1 R2 2M C2 15µF + CBIG 2 R3 845k 3.
PAGE 15
LT1610 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0.118 ± 0.004* (3.00 ± 0.102) 8 7 6 5 0.118 ± 0.004** (3.00 ± 0.102) 0.192 ± 0.004 (4.88 ± 0.10) 1 4 2 3 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 0.034 ± 0.004 (0.86 ± 0.102) 0° – 6° TYP SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) TYP 0.021 ± 0.006 (0.53 ± 0.015) 0.006 ± 0.004 (0.15 ± 0.
PAGE 16
LT1610 U TYPICAL APPLICATIONS N Li-Ion to 3.3V SEPIC DC/DC Converter INPUT Li-ION 3V to 4.2V • 6 VIN + C1 22µF 6.3V 1 5 SW VC FB COMP D1 1M GND PGND 7 4 70 • + 604k SHDN VOUT 3.3V 120mA L2 22µH 2 LT1610 8 80 C3 1µF CERAMIC EFFICIENCY (%) L1 22µH Efficiency 3 C2 22µF 6.3V 60 50 40 30 0.1 C1, C2: AVX TAJB226M006 C3: AVX 1206YC105 (X7R) SHUTDOWN D1: MOTOROLA MBR0520 L1, L2: MURATA LQH3C220 (UNCOUPLED) OR SUMIDA CLS62-220 (COUPLED) 1610 TA15 + 4 CELLS C1 22µF 6.