LTC3548 Linear Technology, LTC3548 Datasheet
LTC3548
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LTC3548 Summary of contents
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... SW1 AT 800mA 33pF V V FB1 FB2 604k GND 301k 10µF LTC3548 Dual Synchronous, U ® 3548 is a dual, constant frequency, synchronous operation provides high efficiency at light loads, LTC3548 Efficiency Curve 100 95 90 EFFICIENCY 85 = 1.8V 80 POWER LOSS 3.3V 1.8V IN OUT 65 Burst Mode OPERATION ...
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... SW(LKG Ambient Operating Temperature Range (Note 2) ................................... – 40°C to 85°C Junction Temperature (Note 5) ............................. 125°C + 0.3V IN Storage Temperature Range ................. – 65°C to 125°C + 0.3V IN Lead Temperature (Soldering, 10 sec) + 0.3V IN LTC3548EMSE only .......................................... 300° ORDER PART NUMBER V 1 FB1 RUN1 2 LTC3548EDD SW1 ...
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... Note 2: The LTC3548 is guaranteed to meet specified performance from 0°C to 70°C. Specifications over the – 40°C and 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: The LTC3548 is tested in a proprietary test mode that connects W U TYPICAL PERFOR A CE CHARACTERISTICS ...
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... LTC3548 W U TYPICAL PERFOR A CE CHARACTERISTICS Reference Voltage vs Temperature 0.615 V = 3.6V IN 0.610 0.605 0.600 0.595 0.590 0.585 –50 – 100 125 TEMPERATURE (°C) 3548 G07 Efficiency vs Load Current 100 95 90 Burst Mode OPERATION 85 80 PULSE SKIP MODE 3.6V 1.8V ...
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... Nominal voltage for this pin is 0.6V. or GND, Burst Mode Exposed Pad (GND) (Pin 11): Power Ground. Connect to the (–) terminal of C connected to electrical ground on PCB. LTC3548 to GND and (–) terminal Must be OUT ...
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... V 10 FB2 U OPERATIO The LTC3548 uses a constant frequency, current mode architecture. The operating frequency is set at 2.25MHz and can be synchronized to an external oscillator. Both channels share the same clock and run in-phase. To suit a variety of applications, the selectable Mode pin allows the user to choose between low noise and high efficiency. ...
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... P-channel switch increases with decreasing input supply voltage (See Typical Performance Characteristics). Therefore, the user should calculate the power dissipation when the LTC3548 is used at 100% duty cycle with low input voltage (See Thermal Considerations in the Applica- tions Information Section). is below 0.35V, shut- ...
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... The choice of which style inductor to use often depends more on the price vs size requirements and any radiated field/EMI require- ments than on what the LTC3548 requires to operate. Table 1 shows some typical surface mount inductors that work well in LTC3548 applications. Input Capacitor (C ...
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... In addition, the high Q of ceramic capacitors along with trace inductance can lead to significant ringing. In most cases, 0.1µF to 1µF of ceramic capacitors should also be placed close to the LTC3548 in parallel with the main capacitors for high frequency decoupling 2. ...
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... Connecting this pin to ground selects pulse skipping mode, which provides the lowest output ripple, at the cost of low current efficiency. The LTC3548 can also be synchronized to an external 2.25MHz clock signal by the MODE/SYNC pin. During synchronization, the mode is set to pulse skipping and the top switch turn-on is synchronized to the rising edge of the external clock ...
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... The junction temperature RISE As an example, consider the case when the LTC3548 is in dropout on both channels at an input voltage of 2.7V with a load current of 400mA and 800mA and an ambient )(1 – D) temperature of 70°C. From the Typical Performance Char- acteristics graph of Switch Resistance, the R tance of the main switch is 0.425Ω ...
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... J which is below the absolute maximum junction tempera- ture of 125°C. Design Example As a design example, consider using the LTC3548 in an portable application with a Li-Ion battery. The battery provides 2.8V to 4.2V. The load requires a maxi- IN mum of 800mA in active mode and 2mA in standby mode. ...
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... OUT1 AT 800mA C4, 33pF V OUT2 604k 10µF 301k C OUT2 3548 F03 BOLD LINES INDICATE HIGH CURRENT PATHS Figure 4. LTC3548 Layout Diagram (See Board Layout Checklist) Low Ripple Buck Regulators Using Ceramic Capacitors 10µF 100k RUN2 V RUN1 IN POR LTC3548 ...
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... C1, C2: MURATA GRM219R60J106KE19 C3: MURATA GRM219R60J475KE19 L1: COILTRONICS LPO3310-222MX L2: COILTRONICS LPO3310-472MX * GREATER THAN 3" FROM POWER SOURCE, ADDITIONAL CAPACITANCE MAY BE REQUIRED. 14 1mm Profile Core and I/O Supplies C1* 10µF RUN2 V RUN1 IN MODE/SYNC POR LTC3548 L2 L1 4.7µH 2.2µH SW2 SW1 C5, 68pF V V FB1 FB2 R4 GND R3 887k ...
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... TYP GAUGE PLANE 0.53 ± 0.152 (.021 ± .006) DETAIL “A” 0.18 (.007) SEATING PLANE 0.17 – 0.27 (.007 – .011) TYP LTC3548 R = 0.115 0.38 ± 0.10 TYP 6 10 3.00 ±0.10 1.65 ± 0.10 (4 SIDES) (2 SIDES) (DD10) DFN 1103 5 1 0.25 ± 0.05 0.75 ±0.05 0.50 BSC 2.38 ± ...
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... Linear Technology Corporation 16 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 2. 4.2V C1 10µF RUN2 V RUN1 IN MODE/SYNC POR L2 LTC3548 D1 15µH SW2 SW1 C5, 22pF FB2 R4 GND C3 R3 887k 4.7µF 196k C1, C2: TAIYO YUDEN JMK316BJ106ML L1: MURATA LQH32CN2R2M33 C3: MURATA GRM21BR60J475KA11B ...