MAX1626 Maxim Integrated Products, MAX1626 Datasheet
MAX1626
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MAX1626 Summary of contents
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... PC board area and system costs. The output voltage is preset 3.3V for the MAX1626 and adjustable for the MAX1627. Input volt- ages can 16.5V. The MAX1626/MAX1627 are functional upgrades for the MAX1649/MAX1651. ________________________Applications PCMCIA Power Supplies Personal Digital Assistants ...
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... Lead Temperature (soldering, 10sec) .............................+300°C = 0°C to +85°C, unless otherwise noted.) CONDITIONS Operating, no load V+ = SHDN = 16.5V (shutdown) Circuit of Figure 1, 3 (Note 1) Circuit of Figure 1, 3 (Note 1) MAX1626, 3/5 = V+, output forced to 5V MAX1627, includes hysteresis MAX1627 SHDN = 3 Output forced to 0V Output in regulation 6.0V < ...
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... LOAD (A) _______________________________________________________________________________________ = -40°C to +85°C, unless otherwise noted.) (Note 2) CONDITIONS Operating, no load V+ = SHDN = 16.5V (shutdown) Circuit of Figure 1, 3 Circuit of Figure 1, 3 MAX1626, 3/5 = V+, output forced to 5V MAX1627, includes hysteresis MAX1627 I = 0µA LOAD EFFICIENCY vs. LOAD CURRENT (V = +3.3V) OUT 100 ...
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... V+ QUIESCENT CURRENT vs. TEMPERATURE +16V +10V + OUT FORCED TO 3.4V 60 -60 -40 - 100 120 140 TEMPERATURE (°C) 4 _______________________________________________________________________________________ MAX1626 EXT OFF TIME vs. OUTPUT VOLTAGE + 3 3/5 = GND OUTPUT VOLTAGE (V) EXT RISE AND FALL TIMES ...
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... TEMPERATURE (°C) MAX1626 LOAD-TRANSIENT RESPONSE A B 100 s/div 3.3V, LOAD = 30mA to 2A OUT A: OUT, 50mV/div, 3.3V DC OFFSET B: LOAD CURRENT, 1A/div _______________________________________________________________________________________ MAX1626 SHUTDOWN RESPONSE TIME AND SUPPLY CURRENT 8V 5V, LOAD = 1A OUT A: OUT, 2V/div B: SUPPLY CURRENT, 1A/div C: SHDN, 5V/div MAX1626 LINE-TRANSIENT RESPONSE ...
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... FUNCTION Sense input for fixed 5V or 3.3V output operation. OUT is internally connected to an on-chip voltage divider (MAX1626). It does not supply current. Leave OUT uncon- nected during adjustable-output operation (MAX1627). Feedback Input for adjustable-output operation. Connect to an external voltage divider between the output and GND (see the Setting the Output Voltage section). ...
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... If the output is low by 30% or more, the minimum off-time increases, allowing soft-start. The error comparator has 0.5% hysteresis for improved noise immunity. In the MAX1626, the 3/5 pin selects the output voltage (Figure 2). In the MAX1627, external feedback resistors at FB adjust the output. Operating Modes ...
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... This compensates for reduced nega- tive inductor current slope due to low output voltages. ________________Design Information at 5V, typical The MAX1626’s output voltage can be selected to 3. under logic control by using the 3/5 pin. The 3/5 pin requires less than 0.5V to ensure a 3.3V output, or more than (V+ - 0.5)V to guarantee a 5V output. The voltage sense pin (OUT) must be connected to the out- put for the MAX1626 ...
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... Calculate the minimum inductance value as follows (MIN) where 2µs is the minimum on-time. Inductor values between two and six times L 3.5 V 3.0 2.5 2.0 1.5 1.0 0 3.0 Figure 6b. MAX1626 3.3V-Operation Current-Sense Resistor Graph FROM OUTPUT Inductor Selection (MAX) OUT = V CS MIN ( ) ...
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... Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers With high inductor values, the MAX1626/MAX1627 will begin continuous-conduction operation at a lower frac- tion of the full load (see Detailed Description ). Low-value inductors may be smaller and less expensive, but they result in greater peak current overshoot due to current- sense comparator propagation delay ...
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... Pursuing output ripple lower than the error compara- tor’s hysteresis (0.5% of the output voltage) is not prac- tical, since the MAX1626/MAX1627 will switch as needed, until the output voltage crosses the hysteresis threshold. Choose an output capacitor with a working voltage rating higher than the output voltage. ...
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... MAX1651 are preferable for special applications where a 100% duty cycle is undesirable, such as flyback and SEPIC circuits. Since the MAX1626’s pinout is similar to those of the MAX649 and MAX1649 family parts, the MAX1626 can be substituted (with minor external component value changes) into fixed-output mode applications, provided the PC board layout is adequate ...
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... C U1: MOTOROLA MMSF3P02HD R2 Figure 8. MAX1627 Typical Operating Circuit ________________________Applications The MAX1626/MAX1627 typical operating circuits (Figures 1 and 8) are designed to output output voltage. The following circuits provide examples and guidance for other applications. Micropower Step-Down Converter When designing a low-power, battery-based applica- ...
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Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers VIA VIAS VIA COMPONENT PLACEMENT GUIDE—COMPONENT SIDE COPPER ROUTING—BACK SIDE Figure 11. Recommended PC Board Design for 6A Step-Down Converter 14 ______________________________________________________________________________________ COPPER ROUTING—FRONT SIDE ...
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Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers ___________________Chip Topography OUT GND GND 3/5 (FB) SHDN REF 0.081" (2.06mm ARE FOR MAX1627 TRANSISTOR COUNT: 375 SUBSTRATE CONNECTED TO V+ ______________________________________________________________________________________ EXT 0.105" (2.63mm ...
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Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Down DC-DC Controllers ________________________________________________________Package Information ______________________________________________________________________________________ 0°-8° 0.101mm 0.004in Narrow SO SMALL-OUTLINE PACKAGE (0.150 in.) INCHES MILLIMETERS DIM MIN MAX MIN MAX A 0.053 ...