MAX857 Maxim Integrated Products, MAX857 Datasheet
MAX857
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MAX857 Summary of contents
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... The MAX856/MAX858 accept a positive input voltage between 0.8V and V and convert higher, pin-selectable output voltage of 3.3V or 5V. The MAX857/MAX859 adjustable versions accept 0.8V to 6.0V input voltages and generate higher adjustable output voltages in the 2.7V to 6.0V range. Typical efficiencies are greater than 85%. Typical quies- cent supply current is 25µ ...
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... Output Voltage Minimum Start- 0mA LOAD Supply Voltage Minimum Operating Voltage Quiescent Supply Current 0mA, 3/ LOAD 3.3V Mode (Note 2) (FB = 1.5V, MAX857/MAX859 only) No Load Battery Current Output set for 3.3V, measured at V — — — – Shutdown Quiescent Current 0V, 3/ (Note 2) ( ...
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... LBI = 1.5V 1.5V, FB Voltage MAX857/MAX859 Output Voltage Range MAX857/MAX859, I Note 2: Supply current from the 3.3V output is measured with an ammeter between the 3.3V output and OUT pin. This current correlates directly with actual battery supply current, but is reduced in value according to the step-up ratio and efficiency ...
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... A 0 1.5 2.0 2.5 3.0 3.5 INPUT VOLTAGE (V) MAX856/MAX857 MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT 1. OUT 1.10 1.05 1.00 V OUT 0.95 0.90 0.85 0.80 0.75 0 4.0 LOAD CURRENT (mA) MAX856/MAX857 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE 400 350 300 250 V = 3.3V OUT 200 V = 5.0V OUT 150 100 50 0 4.0 1.0 1.5 2.0 2.5 3.0 3.5 INPUT VOLTAGE (V) MAX858/MAX859 NO LOAD BATTERY CURRENT vs. INPUT VOLTAGE 1 +85°C 1 ...
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... I = 100mA 5ms/div 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 LOAD MAX856/MAX857 50 s/div 2ms/div = 25mA 5ms/div 5 ...
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... Connect OUT to the regulator output. OUT provides bootstrap power to the IC. Power Ground. Must be low impedance; solder directly to ground plane. N-Channel Power-MOSFET Drain 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 1 (MAX858/MAX859), resulting in a switch voltage drop ( about 500mV under high output loads ...
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... MINIMUM OFF-TIME ONE-SHOT SHDN 3/5* MAXIMUM ON-TIME TRIG ONE-SHOT ONE-SHOT MAX856–MAX859 LBO LBI *MAX856/MAX858 ONLY **MAX857/MAX859 ONLY Figure 1. Block Diagram _______________________________________________________________________________________ 3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters TRIG Q ONE-SHOT F CURRENT-LIMIT COMPARATOR ERROR COMPARATOR N LBI COMPARATOR REFERENCE GND OUT ** * FB REF OUT ...
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... D times FB’s bias current 1N5817 V OUT C2 OUTPUT SELECT C3 0 FOR MAX857 FOR MAX859 Figure 2b. Standard Application Circuit—Adjustable Output Voltage _________ ) OUT REF R2 = 1.25V. V OUT V REF to 300k ) can be used V IN C1* ...
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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. The inductor’ ...
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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 PIN-PACKAGE 8 SO SHDN 8 µMAX Dice* 3 † 8 CERDIP µMAX Dice* REF 8 SO † 8 CERDIP 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 2.6 0.85 1.8 0.210 2.2 0.150 2 ...
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Adjustable-Output, Step-Up DC-DC Converters ________________________________________________________Package Information ______________________________________________________________________________________ C 0.101mm 0.004 in L 8-PIN MAX MICROMAX SMALL OUTLINE PACKAGE 0.101mm 0.004in Narrow ...