LTC3409 LINER [Linear Technology], LTC3409 Datasheet
LTC3409
Available stocks
Related parts for LTC3409
LTC3409 Summary of contents
Page 1
... Supply current during Burst Mode operation is only 65µA dropping to <1µA in shutdown. The 1.6V to 5.5V input voltage range makes the LTC3409 ideally suited for single cell Li-Ion, Li-Metal and 2-cell alkaline, NiCd or NiMH battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems ...
Page 2
... OUT LOAD V = 103 OUT LOAD 5.5V RUN IN SYNC = GND SYNC = V IN When SYNC Input is Toggling (Note 7) RUN↑ ORDER PART NUMBER 8 SYNC LTC3409EDD 7 RUN MODE 5 DD PART MARKING LBNM = 43° 25°C. A MIN TYP MAX ● 0.3 0.65 1.1 0.01 1 ● ...
Page 3
... 0V 5V RUN SW IN Note 4: The LTC3409 is tested in a proprietary test mode that connects V to the output of the error amplifier. FB Note 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. Note 6: ∆V is the amount V OVL voltage ...
Page 4
... LTC3409 W U TYPICAL PERFOR A CE CHARACTERISTICS (From Typical Application on the front page except for the resistive divider resistor values) Efficiency/Power Lost vs Load Current 1.8V OUT 100 0 100 1000 LOAD CURRENT (mA) 3409 G01 1: 2 ...
Page 5
... IN 5000 4000 3000 MAIN SWITCH 2000 SYNCHRONOUS SWITCH 1000 0 – 100 125 –25 0 TEMPERATURE (°C) 3409 G14 LTC3409 Output Voltage vs Load Current V = 1.6V IN 1.22 1.21 1.2V OUT BURST 1.20 1.2V OUT PULSE SKIP 1.19 1.18 0 100 200 300 400 500 600 700 800 900 LOAD CURRENT (mA) ...
Page 6
... LTC3409 W U TYPICAL PERFOR A CE CHARACTERISTICS (From Typical Application on the front page except for the resistive divider resistor values) Start-Up from Shutdown RUN 2V/DIV V OUT 1V/DIV INDUCTOR CURRENT 500mA/DIV 200µs/DIV Load Step 50mA to 600mA Pulse Skip V OUT 100mV/DIV I LOAD ...
Page 7
... SYNC signal should swing at least 0.3V below and above this nominal value (0.33V to 0.93V). Do not leave SYNC floating. GND (Pin 9): Exposed Pad. The Exposed Pad is ground. It must be soldered to PCB ground to provide both electrical contact and optimum thermal performance. LTC3409 3409f 7 ...
Page 8
... Comparator OVDET guards against transient overshoots >10% by turning the main switch off and keeping it off until the transient has ended. Burst Mode Operation The LTC3409 is capable of Burst Mode operation in which pin, described in FB the internal power MOSFETs operate intermittently based on load demand. To enable Burst Mode operation, simply connect the MODE pin to GND ...
Page 9
... This process repeats at a rate that is dependent on the load demand. Short-Circuit Protection When the output is shorted to ground the LTC3409 limits the synchronous switch current to 1.5A. If this limit is exceeded, the top power MOSFET is inhibited from turn- ing on until the current in the synchronous switch falls below 1 ...
Page 10
... The choice of which style inductor to use often depends more on the price vs size requirements and any radiated field/EMI requirements than on what the LTC3409 requires to operate. Table 1 shows some typical surface mount inductors that work well in LTC3409 applications. 10 ...
Page 11
... Their high ripple current, high voltage rating and low ESR make them ideal for switching regulator applications. Because the LTC3409’s control loop does not depend on the output capacitor’s ESR for stable operation, ceramic capacitors can be used to achieve very low output ripple and small circuit size ...
Page 12
... J where example, consider the LTC3409 in dropout at an input voltage of 1.6V, a load current of 600mA and an ambient temperature of 75°C. From the typical perfor- mance graph of switch resistance, the R and the duty cycle P-channel switch at 75°C is approximately 0.48Ω. There- fore, power dissipated by the part is: )(1 – ...
Page 13
... Board Layout Considerations When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC3409. These items are also illustrated graphically in the layout diagram of Figure 3. Check the following in your layout. 1. Does the capacitor C connect to the power V ...
Page 14
... U U APPLICATIO S I FOR ATIO Design Example As a design example, assume the LTC3409 is used in a 2-alkaline cell battery-powered application. The V operating from a maximum of 3.2V down to about 1.8V. The load current requirement is a maximum of 600mA but most of the time it will be in standby mode, requiring only 2mA ...
Page 15
... Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) 0.675 ±0.05 PACKAGE OUTLINE 0.50 BSC 2.38 ±0.05 (2 SIDES 0.115 3.00 ±0.10 1.65 ± 0.10 (4 SIDES) (2 SIDES) 0.25 ± 0.05 0.75 ±0.05 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD LTC3409 0.38 ± 0.10 TYP 5 8 (DD8) DFN 1203 4 1 0.50 BSC 2.38 ±0.10 (2 SIDES) 3409f 15 ...
Page 16
... Synchronous Step-Down OUT DC/DC Converter LTC3411 1.25A (I ), 4MHz, Synchronous Step-Down OUT DC/DC Converter VLDO and ThinSOT are trademarks of Linear Technology Corporation. Linear Technology Corporation 16 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● LTC3409 2.2µ 22pF RUN 4.7µF 5 ...