MAX8505 MAXIM [Maxim Integrated Products], MAX8505 Datasheet
MAX8505
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MAX8505 Summary of contents
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... Rev 0; 10/03 3A, 1MHz, 1% Accurate, Internal Switch Step-Down Regulator with Power-OK General Description The MAX8505 step-down regulator operates from a 2.6V to 5.5V input and generates an adjustable output voltage from 0.8V to 0.85 ✕ VIN 3A. With a 2.6V to 5.5V bias supply, the input voltage can be as low as 2.25V. ...
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... FB to POK Delay COMP COMP Transconductance Gain from FB to COMP 2 _______________________________________________________________________________________ Operating Temperature Range + 0.3V) MAX8505EEE...................................................-40°C to +85°C CC Storage Temperature Range .............................-65°C to +150°C Junction Temperature ......................................................+150°C Lead Temperature (soldering, 10s) .................................+300°C = 1.25V 0.01µ 0°C to +85°C, unless otherwise noted.) ...
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Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS (continued +3.3V 0.8V CTL FB PARAMETER SYMBOL COMP Clamp Voltage, Low COMP Clamp Voltage, High COMP Shutdown ...
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Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS ( +3.3V 0.8V CTL FB PARAMETER SYMBOL IN AND Voltage Range V V Voltage Range ...
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Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS (continued +3.3V 0.8V CTL FB PARAMETER SYMBOL LX Maximum Duty Cycle LX Minimum Duty Cycle SLOPE COMPENSATION ...
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Accurate, Internal Switch Step-Down Regulator with Power-OK (Typical values are 5V CTL EFFICIENCY vs. OUTPUT CURRENT ( 5V 1MHz ...
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... OUTPUT VOLTAGE (V) GND-MEASURED TEMPERATURE vs. OUTPUT CURRENT 120 T = +85°C A 100 T = +25° 5V 1.5V OUT -40° 3.00 3.25 3.50 3.75 4.00 OUTPUT CURRENT (A) TRANSIENT RESPONSE ( 1.2V) IN OUT MAX8505 toc13 OUTPUT VOLTAGE AC-COUPLED 100mV/div 2.25A 0.75A 0 40µs/div OUTPUT CURRENT 1A/div 7 ...
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... TRANSIENT RESPONSE DURING SOFT-START V OUT 500mV/div V CTRL 5V/div INPUT CURRENT 1A/div V POK 5V/div SWITCHING WAVEFORM ( 1.2V 2.5A) IN OUT OUT MAX8505 toc15 V LX 2V/div INDUCTOR CURRENT AC-COUPLED 2A/div V OUT AC-COUPLED 20mV/div 200ns/div MAX8505 toc17 V OUT 100mV/div I OUT 2A/div 100µs/div ...
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... Controller Block Function The MAX8505 step-down converter uses a PWM current-mode control scheme. An open-loop comparator compares the voltage-feedback error signal against the sum of the amplified current-sense signal and the slope compensation ramp. At each rising edge of the internal clock, the internal high-side MOSFET turns on until the PWM comparator trips ...
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... A minimum capacitance of 0.01µF at REF is recom- mended to reduce the susceptibility to switching noise. The MAX8505 also includes an open-drain POK output that indicates when the regulator output is within ±12% of its nominal output. If the output voltage moves outside this range, the POK output is pulled to ground. ...
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... Accurate, Internal Switch Step-Down Regulator with Power-OK Output Voltage Selection The output voltage of the MAX8505 can be adjusted from 0.8V to 85% of the input voltage at 500kHz 80% of the input voltage at 1MHz. This is done by connecting a resistive-divider (R2 and R3) between the output and the FB pin (see the Typical Operating Circuit). For best results, keep R3 below 50kΩ ...
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... Use sufficient input bypass capacitance to ensure that the absolute maximum voltage rating of the MAX8505 is not exceeded in any condition. When input supply is not located close to the MAX8505, a bulk bypass input capacitor may be needed. Compensation Design The double pole formed by the inductor and output ...
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... Place the feedback resistors as close to the IC as possible. 6) Route high-speed switching nodes away from sen- sitive analog areas (FB, COMP). TRANSISTOR COUNT: 3352 PROCESS: BiCMOS D1 C7 (CENTRAL CMOSH-3) 0.1µF BST 3300pF R7 MAX8505 10Ω PGND 0.1µF R6 51kΩ 20kΩ COMP CTL REF C6 POK 0.01µ ...
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... Accurate, Internal Switch Step-Down Regulator with Power-OK REFERENCE MAX8505 25µA REF 25µA 14 ______________________________________________________________________________________ 1.25V FB UVLO GND PWM GND COMP CTL Functional Diagram POK N 50µ BST PGND ...
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Accurate, Internal Switch Step-Down Regulator with Power-OK (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of ...