MAX858 Maxim Integrated Products, MAX858 Datasheet
MAX858
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MAX858 Summary of contents
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... MOSFET power transistor permits high switching frequencies. This benefit, combined with internally set peak inductor current limits, permits the use of small, low-cost inductors. The MAX856/MAX857 have a 500mA peak inductor current limit. The MAX858/MAX859 have a 125mA peak inductor current limit. ________________________Applications 3. Step-Up Conversion ...
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... MAX856 3V, 0mA I 150mA LOAD MAX857 5V, 0mA I 100mA OUT LOAD – – MAX858 0V, 0mA I 25mA LOAD – – MAX858 3V, 0mA I 35mA LOAD MAX859 5V, 0mA I 25mA OUT LOAD – – 3V, LBI = 1.5V 3.47V, OUT in Figure 2, R3 omitted. IN – – MAX85_C 5 = 3V, LBI = 1.5V ...
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... EFFICIENCY vs. OUTPUT CURRENT 100 100 1000 0.001 = +25°C.) A 0.4 V 1.6 V ±100 nA 1.22 1.25 1.28 V 2.7 6.0 V MAX858/MAX859 OUT 1.5V IN 0.1 1 0.01 10 100 1000 LOAD CURRENT (mA) MAX856/MAX857 V = 3.3V OUT 2. 100 1000 0.01 LOAD CURRENT (mA) ...
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... INPUT VOLTAGE (V) MAX858/MAX859 MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT 1.4 1.3 1 OUT 1.1 1.0 0.9 0.8 0 100 LOAD CURRENT (mA) MAX858/MAX859 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE 100 3.3V OUT 5.0V OUT 1.0 1.5 2.0 2.5 3.0 3 ...
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... IN LOAD _______________________________________________________________________________________ 3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters LOAD-TRANSIENT RESPONSE (5V MODE) V OUT 50mV/div I LOAD 0mA to 100mA V = 2.5V IN MAX858/MAX859 LOAD-TRANSIENT RESPONSE V OUT 50mV/div I LOAD 0 0mA to 25mA 2.5V IN MAX858/MAX859 START-UP DELAY (5V MODE) V OUT 2V/div V SHDN 5V/div V = 2.5V 25mA IN LOAD MAX856/MAX857 50 s/div 2ms/div 5ms/div 5 ...
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... IN The peak switch current of the internal MOSFET power switch is fixed at 500mA ±100mA (MAX856/MAX857) or 125mA ±25mA (MAX858/MAX859). The switch’s on- resistance is typically 1Ω (MAX856/MAX857) or 4Ω (MAX858/MAX859), resulting in a switch voltage drop ( about 500mV under high output loads. The SW value of V will decrease with light current loads. ...
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... MINIMUM OFF-TIME ONE-SHOT Q SHDN S 3/5* MAXIMUM ON-TIME Q TRIG ONE-SHOT ONE-SHOT MAX856–MAX859 LBO N LBI *MAX856/MAX858 ONLY **MAX857/MAX859 ONLY Figure 1. Block Diagram _______________________________________________________________________________________ 3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters TRIG ONE-SHOT F CURRENT-LIMIT COMPARATOR * * ERROR COMPARATOR LBI COMPARATOR REFERENCE OUT GND OUT ** FB** ** REF 7 ...
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... OUT control inputs (3/5, LBI, or SHDN) floating. __________________Design Procedure Output Voltage Selection For the MAX856/MAX858,you can select a 3. output voltage under logic control tying 3/ GND or OUT. Efficiency is typically better than 80% over a 2mA to 100mA (MAX856/MAX857) load range. The device is internally bootstrapped, with power derived from the output voltage (via OUT) ...
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... The inductor’s incremental saturation current rating should be greater than the peak switch-current limit, which is 500mA for the MAX856/MAX857, and 125mA for the MAX858/MAX859. However generally acceptable to bias the inductor into saturation by as much as 20%, although this will slightly reduce efficiency. ...
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Adjustable-Output, Step-Up DC-DC Converters Table 1. Component Suppliers PRODUCTION INDUCTORS METHOD Surface Mount See Table 2 Miniature Sumida Through Hole RCH654-220 Renco RL 1284-22 Low-Cost Through Hole CoilCraft PCH-27-223 COMPANY PHONE AVX USA: (207) 282-5111 CoilCraft USA: (708) ...
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... Topography SHDN 3/5 OR FB* † REF † LBO *3/5 FOR MAX856/MAX858; FB FOR MAX857/MAX859. TRANSISTOR COUNT: 357; SUBSTRATE CONNECTED TO OUT. RATED CURRENT HEIGHT (A) (mm) 1.0 5.0 0.8 4.5 0.540 3.2 0.760 3.2 0.320 2.6 0.220 2 ...
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Adjustable-Output, Step-Up DC-DC Converters ________________________________________________________Package Information A 0.101mm 0.004 ______________________________________________________________________________________ C L 8-PIN MAX MICROMAX SMALL OUTLINE PACKAGE 0°-8° 0.101mm 0.004in ...