Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Holder MSOP 10 EP

LTC3103

3103f

TYPICAL APPLICATION

FEATURES DESCRIPTION

1.8µA Quiescent Current,

15V, 300mA Synchronous

Step-Down DC/DC

Converter

The LTC

3103 is a high efficiency, monolithic synchronous

step-down converter using a current mode architecture

capable of supplying 300mA of output current.

The LTC3103 offers two operational modes: automatic

Burst Mode operation and forced continuous mode allow-

ing the user the ability to optimize output voltage ripple,

noise and light load efficiency. With Burst Mode operation

enabled, the typical DC input supply current at no load

drops to 1.8µA maximizing the efficiency for light loads.

Selection of forced continuous mode provides very low

noise constant frequency, 1.2MHz operation.

Additionally, the LTC3103 includes an accurate RUN com-

parator, thermal overload protection, a power good output

and an integrated soft-start feature to guarantee that the

power system start-up is well controlled.

APPLICATIONS

Ultralow Quiescent Current: 1.8µA

Synchronous Rectification: Efficiency Up to 95%

Wide V

Range: 2.5V to 15V

Wide V

OUT

Range: 0.6V to 13.8V

300mA Output Current

User-Selectable Automatic Burst Mode

or Forced

Continuous Operation

Accurate and Programmable RUN Pin Threshold

1.2MHz Fixed Frequency PWM

Internal Compensation

Power Good Status Output for V

OUT

Available in Thermally Enhanced 3mm × 3mm ×

0.75mm, 10-Pin DFN and 10-Pin MSOP Packages

Remote Sensor Networks

Distributed Power Systems

Multicell Battery or SuperCap Regulator

Energy Harvesters

Portable Instruments

Low Power Wireless Systems

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

of Linear Technology Corporation. All other trademarks are the property of their respective

owners.

0.022µF

BST3V TO 15V

MODE SW

RUN PGOOD

LTC3103

GND

665k

10µH

2.2V

300mA

3103 TA01a

47µF

1µF

10µF

1.78M

12pF

Efficiency vs Output Current

OUTPUT CURRENT (A)

EFFICIENCY (%)

POWER LOSS (mW)

100

0.0001 0.01 0.1 1

3103 TA01b

50 0.1

100

0.001

= 3V

= 5V

= 10V

= 15V

Summary of content (20 pages)

PAGE 1
LTC3103 1.8µA Quiescent Current, 15V, 300mA Synchronous Step-Down DC/DC Converter DESCRIPTION FEATURES n n n n n n n n n n n Ultralow Quiescent Current: 1.8µA Synchronous Rectification: Efficiency Up to 95% Wide VIN Range: 2.5V to 15V Wide VOUT Range: 0.6V to 13.8V 300mA Output Current User-Selectable Automatic Burst Mode® or Forced Continuous Operation Accurate and Programmable RUN Pin Threshold 1.
PAGE 2
LTC3103 ABSOLUTE MAXIMUM RATINGS (Note 1) VIN.............................................................. –0.3V to 18V SW................................................. –0.3V to (VIN + 0.3V) FB ................................................................. –0.3V to 6V BST......................................... (SW – 0.3V) to (SW + 6V) RUN, MODE ................................................ –0.3V to VIN VCC, PGOOD.................................................. –0.
PAGE 3
LTC3103 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 10V unless otherwise noted. PARAMETER CONDITIONS Feedback Voltage (Note 5) Feedback Voltage Line Regulation VIN = 2.5V to 15V (Note 5) Feedback Input Current (Note 5) Oscillator Frequency MIN l 0.588 l l TJ = 0°C to 85°C (Note 4) 0.930 1 TYP MAX 0.6 0.612 V 0.02 0.05 %/V 1 20 1.2 1.2 1.55 1.
PAGE 4
LTC3103 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Output Current 100 90 85 85 80 75 70 65 VIN = 4V VIN = 7V VIN = 10V VIN = 15V 0.01 0.1 0.001 OUTPUT CURRENT (A) 75 70 65 ILOAD = 300mA ILOAD = 100mA ILOAD = 10mA ILOAD = 1mA ILOAD = 100µA 60 55 50 1 12 10 8 INPUT VOLTAGE (V) 4 2 6 14 3103 G01 100 80 80 70 70 60 50 40 0 0.0001 VIN = 3.7V VIN = 5V VIN = 7V VIN = 10V VIN = 15V 0.001 0.01 0.1 OUTPUT CURRENT (A) 50 40 30 10 8 FREQUENCY CHANGE (%) CHANGE IN VFB (%) 1.5 1.0 0.
PAGE 5
LTC3103 TYPICAL PERFORMANCE CHARACTERISTICS PEAK CURRENT LIMIT CHANGE (%) LEAKAGE CURRENT (nA) 350 SYNCHRONOUS RECTIFIER 250 MAIN SWITCH 200 150 100 50 0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 10.0 3.0 7.5 2.8 2.5 0 –2.5 –5.0 –20 10 70 40 TEMPERATURE (°C) RUN 5V/DIV VOUT 1V/DIV PGOOD 5V/DIV IL 100mA/DIV 100 130 Forced Continuous Operation 3103 G13 Start-Up into Pre-Biased Output (Forced Continuous Operation) VBST REFRESH CURRENT PULSES ILOAD = 2mA VIN = 10V L = 10µH VOUT = 2.
PAGE 6
LTC3103 TYPICAL PERFORMANCE CHARACTERISTICS VOUT 200mV/DIV AC-COUPLED VOUT 50mV/DIV AC-COUPLED IL 200mA/DIV IL 100mA/DIV 3103 G19 200µs/DIV ILOAD = LOAD STEP, 5mA TO 300mA VIN = 10V CIN = 10µF L = 10µH VOUT = 2.2V COUT = 47µF VOUT = 9V 9 150 200 100 LOAD CURRENT (mA) 250 –2.0 300 –1.0 COUT = 68µF COUT = 47µF COUT = 22µF 0 10 20 30 ILOAD (mA) 50 40 –1.0 –1.5 –2.0 COUT = 100µF COUT = 68µF COUT = 47µF –2.5 0 20 40 60 ILOAD (mA) 80 100 3103 G25 COUT = 68µF COUT = 47µF COUT = 33µF –1.
PAGE 7
LTC3103 PIN FUNCTIONS VIN (Pin 1): Main Supply Pin. Decouple with a 10µF or larger ceramic capacitor. The capacitor should be as close to the part as possible. SW (Pin 2): Switch Pin Connects to the Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. BST (Pin 3): Bootstrapped Floating Supply for the High Side Gate Drive. Connect to SW through a 22nF (minimum) capacitor.
PAGE 8
LTC3103 BLOCK DIAGRAM C2 1 VIN VCC 6 VCC PRE-REG VCC C3 VCC IBIAS UVLO OSC IPEAK(REF) IPEAK 0.6V 0.8V + UVLO R6 7 RUN VREF + R5 0.8V 10 MODE BURST ENABLE BST 3 CBST IPEAK COMP TOP_ON VREF_GOOD SHUTDOWN SD LOGIC – BOOST CONTROL LOGIC BOT_ON SW ANTICROSS CONDUCT – + TSD – THERMAL SHUTDOWN 9 NC PWM PWM COMP IZERO COMP SLOPE COMP – gm + – VOUT C1 + + SLEEP COMP L1 2 + + – 0.6V SS FB R2 8 R1 SLEEP REF – 0.
PAGE 9
LTC3103 OPERATION The LTC3103 step-down DC/DC converter is capable of supplying 300mA to the load. The output voltage is adjustable over a broad range and can be set as low as 0.6V. Both the power and the synchronous rectifier switches are internal N-channel MOSFETs.
PAGE 10
LTC3103 OPERATION Power Good Status Output Short-Circuit Protection The PGOOD pin is an open-drain output which indicates the output voltage status of the step-down converter. If the output voltage falls 10% below the regulation voltage, the PGOOD open-drain output will pull low. A built-in deglitching delay prevents false trips due to voltage transients on load steps. The output voltage must rise 2% above the falling threshold before the pull-down will turn off.
PAGE 11
LTC3103 APPLICATIONS INFORMATION The basic LTC3103 application circuit is shown as the Typical Application on the front page of this data sheet. The external component selection is determined by the desired output voltage, output current, desired noise immunity and ripple voltage requirements for each particular application. However, basic guidelines and considerations for the design process are provided in this section.
PAGE 12
LTC3103 APPLICATIONS INFORMATION Table 2. Representative Inductor Selection PART NUMBER VALUE (µH) DCR (Ω) MAX DC CURRENT (A) SIZE (MM) W×L×H Coilcraft EPL3015 6.8 0.19 1.00 3.0 × 3.0 × 1.5 LPS3314 10 0.33 0.70 3.3 × 3.3 × 1.3 LPS4018 15 0.26 1.12 4.0 × 4.0 × 1.8 SD3114 6.8 0.30 0.98 3.1 × 3.1 × 1.4 SD3118 10 0.3 0.75 3.2 × 3.2 × 1.8 Cooper-Bussman Murata LQH3NPN 6.8 0.20 1.25 3.0 × 3.0 × 1.4 LQH44PN 10 0.16 1.10 4.0 × 4.0 × 1.7 CDRH3D16 6.8 0.17 0.73 3.8 × 3.
PAGE 13
LTC3103 APPLICATIONS INFORMATION Input Capacitor Selection Minimum Off-Time/On-Time Considerations The VIN pin provides current to the power stages of the buck converter. It is recommended that a low ESR ceramic capacitor with a value of at least 10µF be used to bypass the pin. These capacitors should be placed as close to the pin as possible and should have a short return path to the GND pin.
PAGE 14
LTC3103 APPLICATIONS INFORMATION tied to the RUN pin as shown in Figure 2 to meet specific VIN voltage requirements. If used, note that the external divider current is not included in the LTC3103 quiescent current specification. The rising UVLO threshold can be calculated using the following equation:  R4  VUVLO = 0.8V •  1+   R3  Internal VCC Regulator The LTC3103 uses an internal NMOS source follower regulator off of VIN to generate a low voltage internal rail, VCC.
PAGE 15
LTC3103 TYPICAL APPLICATIONS Portable LF RFID Reader, Dual Lithium-Ion to 3.3V/300mA Regulator with Ultralow IQ VIN BST MODE SW 95 CBST 0.022µF LTC3103 PGOOD RUN PGOOD L1 10µH 1M VOUT 3.3V 300mA R2 2M 10µF VCC 100 FB 90 EFFICIENCY (%) VIN 5V TO 9V Efficiency vs Output Current CFF 12pF GND 1µF VIN = 5V 85 VIN = 9V 80 75 70 65 47µF R1 442k 60 0.0001 3103 TA02a L1: TDK VLC4018 0.001 0.01 0.1 LOAD CURRENT (A) 1 3103 TA02b 12V to 2.
PAGE 16
LTC3103 TYPICAL APPLICATIONS Slolar-Powered 2.2V Supply with Li Battery Backup and Run Threshold Set to Battery Minimum Voltage SDM20E-40C R4 3.09M + + 3.6V TADIRAN AA LITHIUM BATTERY 4.8V, 0.5W SOLAR PANEL MPT4.8-150 (6.5VOC) + CBULK 100µF BST VIN 3.2V RUN THRESHOLD SW RUN R3 715k CIN 10µF CBST 22nF LTC3103 MODE PGOOD FB VCC GND C1 1µF L1 15µH VOUT 2.2V R2 1.
PAGE 17
LTC3103 TYPICAL APPLICATIONS 5V to 1.2V/300mA Low Noise Regulator Using Forced Continuous Operation VIN 5V VIN BST MODE SW LTC3103 ON OFF RUN PGOOD FB PGOOD 1M VOUT 1.2V 300mA CFF 22pF GND 1µF L1 4.7µH R2 402k 10µF VCC CBST 0.022µF 10µF R1 402k 3103 TA05a L1: SUMIDA CDRH4D11NP-4R7N Efficiency vs Output Current 100 90 EFFICIENCY (%) 80 70 60 50 40 30 20 10 0 0.0001 VIN = 2.5V VIN = 3.3V VIN = 5V 0.001 0.01 0.
PAGE 18
LTC3103 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699 Rev C) 0.70 ±0.05 3.55 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 ±0.10 (4 SIDES) R = 0.125 TYP 6 0.40 ± 0.10 10 1.65 ± 0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.
PAGE 19
LTC3103 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MSE Package 10-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1664 Rev H) BOTTOM VIEW OF EXPOSED PAD OPTION 1.88 ± 0.102 (.074 ± .004) 5.23 (.206) MIN 1 0.889 ± 0.127 (.035 ± .005) 0.05 REF 10 0.305 ± 0.038 (.0120 ± .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 3.00 ± 0.102 (.118 ± .
PAGE 20
LTC3103 TYPICAL APPLICATION 12V to 5V/300mA Regulator with High Efficiency, Ultralow IQ (1.8µA with VOUT in Regulation, No Load) VIN 12V VIN BST MODE SW LTC3103 CBST 0.022µF L1 10µH PGOOD 1M RUN PGOOD R2 1.87M 10µF VCC FB CFF 10pF GND 1µF VOUT 5V 300mA 47µF R1 255k 3103 TA06 L1: SUMIDA CDRH4D16FB RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC3104 15V, 300mA Synchronous Step-Down DC/DC Converter with Ultralow Quiescent Current and 10mA LDO VIN: 2.5V to 15V, VOUT(MIN) = 0.