Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Switched-capacitor voltage converter DFN 10

LTC3203/LTC3203-1

LTC3203B/LTC3203B-1

32031fa

APPLICATIO S

TYPICAL APPLICATIO

FEATURES

DESCRIPTIO

The LTC

3203/LTC3203-1/LTC3203B/LTC3203B-1 are low

noise, high efficiency charge pump DC/DC converters

capable of driving loads up to 500mA from a 2.7V to 5.5V

input. Low external parts count (two flying capacitors and

bypass capacitors at V

and V

OUT

) make the LTC3203

family ideally suited for small, battery-powered applica-

tions.

Built-in soft-start circuitry prevents excessive inrush

current during start-up. High switching frequency enables

the use of small external capacitors. The LTC3203/

LTC3203-1 feature Burst Mode operation at light load to

achieve high efficiency whereas the LTC3203B/

LTC3203B-1 operate at constant frequency to achieve

lowest noise operation.

The LTC3203-1/LTC3203B-1 have a user selectable fixed

output voltage of 4.5V or 5V to power LEDs or logic

circuits. The FB pin of the LTC3203/LTC3203B can be used

to program the desired output voltage. The parts are short-

circuit and overtemperature protected and are available in

a low profile (3mm × 3mm) DFN package.

■

High Current LED Backlight Supply for

Cellphones/PDAs

■

Cellphone Camera Light Supply

■

General Purpose 3.3V or Li-Ion to 5V Supply

■

USB ON THE GO(OTG) Devices

■

Selectable Dual Mode Operation: 1:1.5 or 1:2

■

High Output Current: Up to 500mA

■

Low Noise Constant Frequency (1MHz/0.9MHz)

Operation*

■

Range: 2.7V to 5.5V

■

Adjustable Output Voltage (LTC3203/LTC3203B)

■

User Selectable Fixed Output Voltages: 4.5V or 5V

(LTC3203-1 and LTC3203B-1)

■

Burst Mode

Operation with

~ 120µA (LTC3203/LTC3203-1)

■

Constant Freqency Operation at All Loads

(LTC3203B/LTC3203B-1)

■

Soft-Start Limits Inrush Current at Turn-On

■

Short-Circuit/Thermal Protection

■

Shutdown Disconnects Load from Input

■

Shutdown Current: < 1µA

■

Available in a 10-pin (3mm × 3mm) DFN Package

500mA Output Current

Low Noise Dual Mode

Step-Up Charge Pumps

3203 F02

LTC3203-1

ON/OFF

OUTPUT PROGRAMMING

SEL

500mA

SHDN

MODE

GND

OUT

–

2.2µF

10µF

R1*

100k

OUT(MAX)

300mA

500mA

SEL

LOW

HIGH

LOW

HIGH

OUT

4.5V

*R1

316k

357k

402k

(V)

2.5

EFFICIENCY (%)

3.5

4 4.5

3203 G05

100

5.5

OUT

= 4.5V

OUT

= 5V

Efficiency vs V

at 300mA Load Current

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

Burst Mode is a registered trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

*Protected by U.S. Patents including 6411531.

Summary of content (16 pages)

PAGE 1
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LTC®3203/LTC3203-1/LTC3203B/LTC3203B-1 are low noise, high efficiency charge pump DC/DC converters capable of driving loads up to 500mA from a 2.7V to 5.5V input. Low external parts count (two flying capacitors and bypass capacitors at VIN and VOUT) make the LTC3203 family ideally suited for small, battery-powered applications.
PAGE 2
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW VIN, VOUT to GND ......................................... –0.3V to 6V MODE, VSEL/FB, SHDN ..................... –0.3V to VIN +0.3V VOUT Short Circuit Duration ............................. Indefinite IOUT (Note 2)....................................................... 500mA Operating Temperature Range (Note 3) ... –40°C to 85°C Storage Temperature Range ..................
PAGE 3
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full specified temperature range, otherwise specifications are at 25°C. VIN = 3.6V, C1 = C2 = 2.2µF unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS LTC3203-1/LTC3203B-1 VOUT 4.5V Output Voltage Range (VSEL = 0V) (Note 5) VIN > 3.1V, IOUT < 500mA VIN > 2.9V, IOUT < 350mA VIN > 2.7V, IOUT < 250mA ● ● 4.32 4.32 4.32 4.5 4.5 4.5 4.68 4.68 4.
PAGE 4
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C, VIN = 3.6V, C1 = C2 = 2.2µF unless otherwise specified VOUT vs Load Current (4.5V Output Setting) 4.65 5.5 4.8 4.60 5.3 4.6 5.1 4.55 VIN = 3V VIN = 2.7V 4.40 VIN = 3.3V 4.35 4.7 VIN = 3.3V 4.5 VIN = 3.6V VIN = 2.7V 4.3 4.25 0 3.5 1.5x MODE 2x MODE 0 3.2 1.5x MODE 2x MODE 3.0 50 100 150 200 250 300 350 400 450 500 ILOAD (mA) 2.5 3.
PAGE 5
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W TYPICAL PERFOR A CE CHARACTERISTICS Burst Mode Current Threshold vs Supply Voltage (LTC3203/LTC3203-1) No-Load Input Current vs Supply Voltage (LTC3203/LTC3203-1) 160 500 140 450 2x MODE 1.5x MODE 10 350 80 60 300 250 200 1.5x MODE 150 40 1 1.5x MODE IIN – 1.5 • ILOAD 0.1 100 20 2x MODE 50 0 3 3.5 4 VIN (V) 4.5 5 5.5 3 2.5 3.5 4 VIN (V) 4.5 3203 G13 IOUT VIN = 3.6V CIN = 2.
PAGE 6
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U U U PI FU CTIO S C2+ (Pin 1): Flying Capacitor 2 Positive Terminal (C2). VOUT (Pin 2): Regulated Output Voltage. VOUT should be bypassed with a low ESR ceramic capacitor as close to the pin as possible for best performance. The capacitor should have greater than 4.7µF capacitance under all conditions. C1+ (Pin 3): Flying Capacitor 1 Positive Terminal (C1). SHDN (Pin 4): Active Low Shutdown Input.
PAGE 7
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 SW BLOCK DIAGRA LTC3203/LTC3203B LTC3203-1/LTC3203B-1 0.91V + 0.91V + 2x/1.5x 2x/1.5x MODE 6 VSEL – MODE 6 – 5 SHDN 4 SOFT-START AND SHUTDOWN CONTROL SHDN 4 0.91V SOFT-START AND SHUTDOWN CONTROL 5 FB 0.82V 2 VOUT 2 VOUT + + OSCILLATOR + SWITCH CONTROL – 0.
PAGE 8
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U OPERATIO The LTC3203/LTC3203-1/LTC3203B/LTC3203B-1 use a switched capacitor charge pump to boost VIN to a regulated output voltage. Regulation is achieved by sensing the output voltage through a resistor divider and modulating the charge pump output current based on the error signal. A two-phase non-overlapping clock activates the charge pump switches. The typical frequency of charging and discharging the flying capacitors is 1MHz (2x mode) or 0.9MHz (1.5x mode).
PAGE 9
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U OPERATIO When the output voltage drops enough to overcome the burst comparator hysteresis, the part wakes up and commences normal fixed frequency operation. The output capacitor recharges and causes the part to re-enter the Sleep state if the output load still remains less than the Burst Mode threshold. This Burst Mode threshold varies with VIN, VOUT and the choice of output storage capacitor.
PAGE 10
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W U U APPLICATIO S I FOR ATIO Power Efficiency The power efficiency (η) of the LTC3203/LTC3203-1/ LTC3203B/LTC3203B-1 in 1.5x mode is similar to that of a linear regulator with an effective input voltage of 1.5 times the actual input voltage. This occurs because the input current for a 1.5x fractional charge pump is approximately 1.5 times the load current. In an ideal regulating 1.5x charge pump the power efficiency would be given by: η1.
PAGE 11
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W U U APPLICATIO S I FOR ATIO resistor RX. Thus, this configuration will have the highest loop gain giving it the lowest closed-loop output resistance. Likewise it will also require the largest amount of output capacitance to preserve stability. Programming the MODE Pin Effective Open Loop Output Resistance (ROL) When VIN ramps up, the voltage at the MODE pin crosses VMODEH and the chip switches from 2x mode to 1.5x mode.
PAGE 12
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W U U APPLICATIO S I FOR ATIO For the example given, a 5V output setting with ±4% output tolerance and maximum load current of 500mA, a resistor ratio of: RMODE1 >4 RMODE2 at the MODE pin allows the chip to switch modes while maintaining regulation.
PAGE 13
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W U U APPLICATIO S I FOR ATIO 10nH VIN 0.1µF 7 VIN 2.2µF LTC3203* 9, 11 GND 3203 F05 Figure 5. 10nH Inductor Used for Input Noise Reduction A 10nH inductor will reject the fast current notches, thereby presenting a nearly constant current load to the input power supply. For economy the 10nH inductor can be fabricated on the PC board with about 1cm (0.4") of PC board trace.
PAGE 14
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U W U U APPLICATIO S I FOR ATIO Thermal Management For higher input voltages and maximum output current, there can be substantial power dissipation in the LTC3203/ LTC3203-1/LTC3203B/LTC3203B-1. If the junction temperature increases above approximately 150°C, the thermal shutdown circuitry will automatically deactivate the output. To reduce the maximum junction temperature, a good thermal connection to the PC board is recommended.
PAGE 15
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U PACKAGE DESCRIPTIO DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) R = 0.115 TYP 6 0.38 ± 0.10 10 0.675 ±0.05 3.50 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 3.00 ±0.10 (4 SIDES) PACKAGE OUTLINE 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) (DD) DFN 1103 5 0.25 ± 0.05 0.200 REF 0.50 BSC 2.38 ±0.05 (2 SIDES) 1 0.75 ±0.05 0.00 – 0.05 0.25 ± 0.05 0.50 BSC 2.38 ±0.
PAGE 16
LTC3203/LTC3203-1 LTC3203B/LTC3203B-1 U TYPICAL APPLICATIO 7 3 2.2µF 10 332k 100k 1 C2+ C2– 4 2 C1+ LTC3203/ LTC3203B C1– 8 6 VOUT VIN FB 10µF 5 MODE SHDN GND ON OFF 47Ω 47Ω 47Ω 47Ω 47Ω 47Ω 9, 11 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT®1618 Constant Current, Constant Voltage, 1.4MHz High Efficiency Boost Regulator Up to 16 White LEDs, VIN: 1.6V to 18V, VOUT(MAX) = 34V, IQ = 1.8mA, ISD ≤ 1µA, 10-Lead MS Package LTC1911-1.5 250mA (IOUT), 1.