LTC3447 Linear Technology, LTC3447 Datasheet
LTC3447
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LTC3447 Summary of contents
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... In Burst Mode dropping to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3447 ideally suited for single cell Li-Ion battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. Automatic Burst Mode operation increases effi ...
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... –100mA, Wafer Level 0V 5V RUN SW IN Regulated Feedback Voltage (Note 5) (Note 5) (Note 5) (Note 5) www.DataSheet4U.com FOR ATIO ORDER PART NUMBER 10 SDA LTC3447EDD 9 V CCD 8 SCL 7 RUN PART MARKING LBKB = 2.96°C/W JC MIN TYP MAX UNITS 0 460 kΩ ...
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... Note 4: Dynamic supply current is higher due to gate charge being delivered at the switching frequency. , and the power A Note 5: Determined by design, not production tested. Note 6: The LTC3447 is tested in a proprietary test mode that connects V to FB. OUT t SU, STA t ...
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... LTC3447 W U TYPICAL PERFOR A CE CHARACTERISTICS DAC Nonlinearity 0.5 0.4 0.3 0.2 INL 0.1 0 DNL –0.1 –0.2 –0.3 –0.4 –0 DAC 3447 G04 EffIciency and Power Loss vs Load Current (V = 2.5V) IN 100 90 V OUTMAX 80 V OUTMIN LOSS MAX 40 30 LOSS MIN ...
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... TEMPERATURE (° Transition OUT(MIN) OUT(MAX) PULSE SKIP MODE V OUT 500mV/DIV INDUCTOR CURRENT 100mA/DIV 5V/DIV PGOOD 100µs/DIV LTC3447 www.DataSheet4U.com Output Voltage vs Supply Voltage 2.060 2.055 DAC = MAX 2.050 2.045 2.040 2.035 DAC = MIN 2.030 2.025 2.020 2.5 3.5 4.5 ...
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... Exposed Pad (Pin 11): Ground. Must be connected to PCB ground for electrical contact and optimized thermal performance SLEW + SOFT-START BUCK REGULATOR V REF – BURST MUX Figure 2. LTC3447 High Level Block Diagram www.DataSheet4U.com 2 C Clock Input Power Rail Data Input 1.3R MUX ...
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... held at 150mA. The LTC3447 remains in this sleep state until the output voltage falls below the output voltage set- ting. Once this occurs, the regulator wakes up and allows I the inductor to develop 150mA current pulses ...
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... LTC3447 U OPERATIO the user should calculate the power dissipation when the LTC3447 is used at 100% duty cycle with low input voltage (See Thermal Considerations in the Applications Information section). Low Supply Operation The LTC3447 will operate with input supply voltages as low as 2.5V, but the maximum allowable output current is reduced at this low voltage ...
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... U OPERATIO External Start-Up Option The LTC3447 allows for the use of optional external resistors to determine the start-up voltage. Using this option, the start-up voltage can be set to levels inside or outside the DAC output’s operating range. The output voltage will be regulated at this value until the internal DAC is updated and a STOP command is received ...
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... Commands Supported The LTC3447 supports only write byte commands to a single register. During ACK bit periods, the LTC3447 will pull the data line low to acknowledge the master device. See Figure 7. Data Transfer Timing for Write Commands ...
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... The choice of which style induc- = 240mA tor to use often depends more on the price versus size L requirements and any radiated fi eld/EMI requirements than on what the LTC3447 requires to operate. Table 2 shows some typical surface mount inductors that work (1) well in LTC3447 applications. Table 2. ...
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... Output Voltage Programming requirement. The The LTC3447 has an internal resistor divider network tied to the OUT pin. The output voltage is controlled by a DAC (6-bit register) whose setting is programmed via the I (3) interface ...
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... SW node will become high impedance. )(1 – DC) To avoid the LTC3447 from exceeding the maximum junc- tion temperature, the user will need to do some thermal analysis. The goal of the thermal analysis is to determine ...
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... where T is the ambient temperature example, consider the LTC3447 when using an input voltage of 3.6V, an ambient temperature of 70°C, and a buck load current of 500mA. From the typical performance graph of switch resistance, the R DS(ON) switch at 70°C is approximately 0.45Ω. Therefore, power dissipated by the part is: ...
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... U U APPLICATIO S I FOR ATIO Design Example As a design example, assume the LTC3447 is used in a single lithium-ion battery-powered cellular phone applica- tion. The V will be operating from a maximum of 4.2V IN down to about 2.7V. The normal load current requirement is a maximum of 500mA at 1.4V, but most of the time it will be in standby mode, requiring only 200µ ...
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... ThinSOT, VLDO and PowerPath are trademarks of Linear Technology Corporation. Linear Technology Corporation 16 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 Li-Ion Battery to 1.4V/1V Regulator 3 OUT LTC3447 C PGOOD V OUT OUT 4.7 F PWREN RUN V CCD 4 TDK C1608X5R0J475MT IN OUT L1: SUMIDA CDRH3D16-3R3 ...