LTC3631 Linear Technology Corporation, LTC3631 Datasheet
LTC3631
Available stocks
Related parts for LTC3631
LTC3631 Summary of contents
Page 1
... DC supply current at no load while maintaining output voltage regulation. The LTC3631 can supply up to 100mA load current and features a programmable peak current limit that provides a simple method for optimizing effi ciency in lower current applications. The LTC3631’ ...
Page 2
... JMAX JA EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LTC3631EMS8E#PBF LTC3631EMS8E#TRPBF LTC3631EMS8E-3.3#PBF LTC3631EMS8E-3.3#TRPBF LTFFP LTC3631EMS8E-5#PBF LTC3631EMS8E-5#TRPBF LTC3631IMS8E#PBF LTC3631IMS8E#TRPBF LTC3631IMS8E-3.3E#PBF LTC3631IMS8E-3.3#TRPBF LTC3631IMS8E-5#PBF LTC3631IMS8E-5#TRPBF LTC3631EDD#PBF LTC3631EDD#TRPBF LTC3631EDD-3 ...
Page 3
... Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3631E is guaranteed to meet specifi cations from 0°C to 85°C with specifi cations over the –40°C to 125°C operating junction temperature range assured by design, characterization and correlation with statistical process controls ...
Page 4
... LTC3631 www.DataSheet4U.com TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency vs Load Current OUT OUT V = 12V IN FIGURE 10 CIRCUIT 36V 24V 0 LOAD CURRENT (mA) Effi ciency vs Input Voltage OUT FIGURE 10 CIRCUIT 100mA LOAD 10mA LOAD 1mA ...
Page 5
... VOLTAGE (V) IN 3631 G13 RUN Comparator Thresholds vs Temperature 1.300 1.250 RISING 1.200 1.150 FALLING 1.100 1.050 1.000 110 –40 – TEMPERATURE (°C) 3631 G16 LTC3631 Quiescent Supply Current vs Input Voltage 14 12 SLEEP SHUTDOWN VOLTAGE (V) ...
Page 6
... RUN (Pin 5): Run Control Input. A voltage on this pin above 1.2V enables normal operation. Forcing this pin below 0.7V shuts down the LTC3631, reducing quiescent current to approximately 3μA. 6 Load Step Transient Response OUTPUT ...
Page 7
... THROUGH PREVENTION + REVERSE CURRENT – COMPARATOR VOLTAGE REFERENCE FEEDBACK + COMPARATOR 0.800V + – PART NUMBER R1 R2 LTC3631 0 LTC3631-3.3 2.5M 800k LTC3631-5 4.2M 800k LTC3631 OUT C1 5μ OUT 3631 BD R2 IMPLEMENT DIVIDER EXTERNALLY FOR ADJUSTABLE VERSION 3631fa ...
Page 8
... LTC3631 inherently switches at a lower frequency during start-up or short-circuit conditions. Start-Up and Shutdown If the voltage on the RUN pin is less than 0.7V, the LTC3631 enters a shutdown mode in which all internal circuitry is FB disabled, reducing the DC supply current to 3μA. When the voltage on the RUN pin exceeds 1 ...
Page 9
... SET switching. Similarly minimum), an overvoltage detector disables switching. When switching is disabled, the LTC3631 can safely sustain input voltages up to the absolute maximum rating of 60V. Switching is enabled when the input voltage returns to the 4.5V to 45V operating range. LTC3631 ...
Page 10
... LTC3631 www.DataSheet4U.com APPLICATIONS INFORMATION The basic LTC3631 application circuit is shown on the front page of this data sheet. External component selection is determined by the maximum load current requirement and begins with the selection of the peak current programming resistor The inductor value L can then be determined, ...
Page 11
... MOSFET. To prevent large ripple voltage, a low ESR input capacitor sized for the maximum RMS current should be used. Approximate RMS current is given by: 1000 I 3631 F04 RMS LTC3631 Selection OUT , is needed to fi lter the trapezoidal OUT ...
Page 12
... OUT current and stores energy to satisfy the load current when the LTC3631 is in sleep. The output voltage ripple during a burst cycle is dominated by the output capacitor equivalent series resistance (ESR) and can be estimated by the following equation: ...
Page 13
... Characteristics table. The current that fl ows through this divider will directly add to the shutdown, sleep and active current of the LTC3631, and care should be taken to minimize the impact of this current on the overall effi ciency of the application circuit. Resistor values in the megohm range may be required to keep the impact on quiescent shutdown and sleep currents low ...
Page 14
... μA When the LTC3631 detects a fault condition (input supply undervoltage or overvoltage) or when the RUN pin falls below 1.1V, the SS pin is quickly pulled to ground and the internal soft-start timer is reset. This ensures an orderly restart when using an external soft-start capacitor. The duration of the 0.75ms internal peak current soft-start may be increased by placing a capacitor from the I to ground ...
Page 15
... Thermal Considerations The LTC3631 does not dissipate much heat due to its high effi ciency and low peak current level. Even in worst-case conditions (high ambient temperature, maximum peak current and high duty cycle), the junction temperature will exceed ambient temperature by only a few degrees ...
Page 16
... PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC3631. Check the following in your layout: 1. Large switched currents fl the power switches and input capacitor. The loop formed by these compo- nents should be as small as possible ...
Page 17
... GND SET 33k C : TDK C3225X7R1H105KT AVX 08056D106KAT2A OUT L1: MURATA LQH43CN471K03 L1 1000μH V OUT 15V 20mA R1 C OUT 3M 4.7μF R2 169k 3631 TA07a LTC3631 Maximum Load Current vs Input Voltage 100 I OPEN SET V = –3V OUT –5V 80 OUT –12V OUT ...
Page 18
... LTC3631 www.DataSheet4U.com PACKAGE DESCRIPTION 3.5 0.05 1.65 0.05 2.15 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS TOP MARK (NOTE Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) 0.675 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.38 0.05 (2 SIDES) 3.00 0.10 (4 SIDES) PIN 1 0.75 0.05 0.200 REF 0.00 – 0.05 NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2 ...
Page 19
... DETAIL “A” MAX SEATING PLANE 0.22 – 0.38 (.009 – .015) 0.65 TYP (.0256) BSC LTC3631 2.06 0.102 (.081 .004) 1 0.29 REF 1.83 0.102 (.072 .004) 0.05 REF DETAIL “B” CORNER TAIL IS PART OF THE LEADFRAME FEATURE. DETAIL “B” FOR REFERENCE ONLY ...
Page 20
... McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 5V, 100mA Regulator for Automotive Applications L1 100μH V BATT 4.5V TO 45V C IN AND SURVIVES LTC3631 2.2μF TRANSIENTS RUN 60V I SET SS HYST GND C : TDK C3225X7R2A225M KEMET C1210C106K4RAC OUT ...