ml4851 Microsemi Corporation, ml4851 Datasheet
ml4851
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ml4851 Summary of contents
Page 1
... The combination of BiCMOS process technology, internal synchronous rectification, variable frequency operation, and low supply current make the ML4851 ideal for 1 cell applications. The ML4851 is capable of start-up with input voltages as low as 1V and is available in 5V and 3.3V output versions with output voltage accuracy of ± ...
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... NAME FUNCTION 1 V Battery input voltage 200mV reference output REF 3 GND Analog signal ground 4 DETECT Pulling this pin below V RESET pin to go low 2 ML4851 8-Pin SOIC (S08 PWR GND RESET V REF GND OUT DETECT 4 TOP VIEW ...
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... Note 1: Limits are guaranteed by 100% testing, sampling or correlation with worst case test conditions. OPERATING CONDITIONS Temperature Range ML4851CS-X .............................................. 0ºC to 70ºC ML4851ES-X ........................................... –20ºC to 70ºC V Operating Range IN ML4851CS-X ................................ 1. ML4851ES-X ................................ 1. 0.3V Thermal Resistance ( OUT 1A 250mA = Operating Temperature Range (Note 1) A CONDITIONS ...
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... ML4851 Figure 3. PFM Inductor Current Waveforms and Timing (Sumida CD75) IN 100 F ML4851 PWR GND IN RESET REF GND V L DETECT V OUT 100 Figure 1. Application Test Circuit START- 5µs ONE SHOT – ...
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... FUNCTIONAL DESCRIPTION The ML4851 combines Pulse Frequency Modulation (PFM) and synchronous rectification to create a boost converter that is both highly efficient and simple to use. A PFM regulator charges a single inductor for a fixed period of time and then completely discharges before another cycle begins, simplifying the design by eliminating the need for conventional current limiting circuitry ...
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... L = 33µ 18µH 2.5 3.0 Figure 5. Typical Efficiency as a Function of V July, 2000 DATASHEET 250 L = 18µ 33µH ML4851-5 200 150 L = 10µH 100 L = 56µ 1.0 1.5 2.0 2.5 3.0 3 56µH ML4851 33µ 18µ 10µ 1.0 1.5 2.0 2 (V) IN 4.5 3.0 ...
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... Many use a conservative current level, where inductance has dropped to 90% of its normal level. In any case good idea to try inductors of various current ratings with the ML4851 to determine which inductor is the best choice. Check efficiency and maximum output current, and if a current probe is available, look at the inductor current to see if it looks like the waveform shown in Figure 3 ...
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... Keep components as close as possible to the ML4851 Use short trace lengths from the inductor to the V and from the output capacitor to the V Use a single point ground for the ML4851 PWR GND pin and the input and output capacitors, and connect GND to PWR GND with a separate trace A sample PC board layout is shown in Figure 6 ...
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... ML4851CS-5 ML4851ES-3 ML4851ES-5 ML4851IS-3 (obsolete) ML4851IS-5 (obsolete) © Micro Linear 1997 registered trademark of Micro Linear Corporation. All other trademarks are the property of their respective owners. Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; ...