LT1306 Linear Technology Corporation, LT1306 Datasheet
LT1306
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LT1306 Summary of contents
Page 1
... V IN down converter functions to be easily realized using a single inductor. The internal 300kHz oscillator of the LT1306 can be easily synchronized to an external clock from 425kHz to 500kHz. This allows switching harmonics to be tightly controlled and eliminates any beat frequencies that may result from a multifrequency system ...
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... V = 2.2V OUT 0V 7V 7.2V, V OUT IN SW CAP U W INFORMATION ORDER PART NUMBER TOP VIEW 1 8 S/S LT1306ES8 CAP PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO 1306 = 125 open unless otherwise noted. C MIN TYP MAX 1 ...
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... Output Boost-to-Stepdown Threshold Output Stepdown-to-Boost Threshold Note 1: Absolute Maximum Ratings are those values beyond which the life to the device may be impaired. Note 2: The LT1306E is guaranteed to meet performance specifications from Specifications over the – operating W U TYPICAL PERFORMANCE CHARACTERISTICS ...
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... LT1306 W U TYPICAL PERFORMANCE CHARACTERISTICS Shutdown Supply Current vs Input Voltage – INPUT VOLTAGE (V) 1306 • G04 Oscillator Frequency Line Regulation 320 315 310 305 300 ...
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... RECTIFIER CURRENT (A) Continuous-Conduction Mode Switching Waveforms in Stepdown Mode V SW 5V/DIV I L 0.5V/DIV V O 50mV/DIV s/DIV LT1306 Continuous-Conduction Mode Switching Waveforms in Boost Operation V SW 5V/DIV I L 0.5A/DIV V O 0.1V/DIV AC 2 4.2V 2 s/DIV 1306 • G14 Transient Response of the ...
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... S/S pin with a pulse train. – A5 UVLO + – – CLK PWM CONTROL Figure 2. LT1306 Block Diagram – high level determined by the externally IN I > 0 RECT CONTROL CAP IDLE RECTIFIER ...
Page 7
... Q1 conduction. The internal oscillator frequency is 300kHz. The pulse width of the clock determines the maximum on duty ratio of Q1. In the LT1306 this is set to 88%. Q1 turns on at the trailing edge of the clock pulse. To prevent subharmonic oscillation above 50% duty ratio, a com- pensating ramp (generated from the oscillator sawtooth) is added to the sensed Q1 current ...
Page 8
... Driver X5 then turns off and the rectifier, Q2, becomes an open circuit. The LT1306 dissipates only shutdown. The LT1306 is guaranteed to start with a minimum V 1.8V. Comparator A5 senses the input voltage and gen- erates an undervoltage lockout (UVLO) signal if V below this minimum. In UVLO, V stops switching ...
Page 9
... For 1- or 2-cell alkaline or single Li-Ion to 5V applications recommended for the LT1306 running at 300kHz inductor can be used if the LT1306 is externally synchronized at 500kHz The inductor should be able to handle the full load peak inductor current without saturation ...
Page 10
... Capacitor reliability will be affected if the ripple current exceeds the maximum allowable ratings. This maximum rating is usually specified as the RMS ripple current. In the LT1306 the RMS output capacitor ripple current is: V – ...
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... Figure 8 shows a suggested component placement and PC board layout. 3 • • 3 • the compensation Z / ensures adequate gain margin beyond should be placed close to the IC package and OUT LT1306 of the ...
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... CONTROL-TO-OUTPUT TRANSFER FUNCTION BEFORE COMPENSATION ˆ and Error Amplifier ˆ PWM CONTROL Q1 LOGIC RECTIFIER – 1.24V LT1306 GND – MAX L AMPLITUDE RESPONSE OF THE ERROR AMPLIFIER CURRENT LOOP CROSSOVER FREQUENCY ˆ ˆ ...
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... U U APPLICATIONS INFORMATION GROUND PLANE V OUT Figure 8. Recommended Component Placement for LT1306. Notice That the Input and the Output Capacitors Are Grounded at the Same Point. A Ground Plane Under the DC/DC Converter Is Highly Recommended. Use Multiple Vias to Tie Pin 4 Copper to the Ground Plane W U ...
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... LT1306 U TYPICAL APPLICATIO IN1 0.1 F CERAMIC 14 2-Cell NiMH to 3.3V Output 4 CAP IN 2V/500kHz S/S OUT R1 LT1306 + 412k C IN2 GND 95k 249k 39pF C Z 5.6nF 1306 F09 Efficiency ...
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... TYP 0.014 – 0.019 (0.355 – 0.483) TYP LT1306 0.150 – 0.157** (3.810 – 3.988 0.004 – 0.010 (0.101 – 0.254) 0.050 (1 ...
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... LT1306 U TYPICAL APPLICATIO S 4-Cell NiMH to 5V Output 3. CAP IN S/S OUT LT1306 + C C IN1 IN2 GND CERAMIC 75k 22pF C Z 15nF Transient Response with Step Input (4V to 6V) RELATED PARTS PART NUMBER DESCRIPTION LT1302 High Output Current Micropower DC/DC Converter ...