MAX797CSE+T Maxim Integrated Products, MAX797CSE+T Datasheet
MAX797CSE+T
Specifications of MAX797CSE+T
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MAX797CSE+T Summary of contents
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... Notebook and Subnotebook Computers PDAs and Mobile Communicators Cellular Phones Idle Mode is a trademark of Maxim Integrated Products. † U ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ABSOLUTE MAXIMUM RATINGS V+ to GND .................................................................-0.3V, +36V GND to PGND........................................................................± GND ...................................................................-0.3V, +7V BST to GND ...............................................................-0.3V, +36V DH to LX...........................................................-0.3V, BST + 0. BST.....................................................................-7V, +0.3V SHDN ...
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Synchronous Rectifier for CPU Power ELECTRICAL CHARACTERISTICS (continued) (V+ = 15V, GND = PGND = 0V REF = 0A -55°C to +125°C for MAX79_M, unless otherwise noted.) A PARAMETER Reference Output Voltage No ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ELECTRICAL CHARACTERISTICS (continued) (V+ = 15V, GND = PGND = 0V REF = 0A, T PARAMETER +3.3V and +5V STEP-DOWN CONTROLLERS Input Supply Range 0mV < (CSH - ...
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Synchronous Rectifier for CPU Power __________________________________________________Typical Operating Circuits INPUT 4.5V TO 30V INPUT 6V TO 30V _______________________________________________________________________________________ Step-Down Controllers with V+ VL SHDN MAX797 DH BST SS LX REF DL PGND SYNC CSH GND CSL SKIP FB V+ SECFB SHDN ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power _____________________________________Typical Operating Circuits (continued) INPUT 6V TO 30V SHDN MAX799 SS REF GND __________________________________________Typical Operating Characteristics (T = +25°C, unless otherwise noted.) A EFFICIENCY vs. LOAD CURRENT, 5V/3A CIRCUIT 100 V = ...
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Synchronous Rectifier for CPU Power ____________________________Typical Operating Characteristics (continued +25°C, unless otherwise noted.) A QUIESCENT SUPPLY CURRENT vs. SUPPLY VOLTAGE, 5V/3A CIRCUIT IN IDLE MODE 16m 15m 14m STANDARD MAX797 APPLICATION CONFIGURED FOR 5V SKIP = LOW 800µ ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ____________________________Typical Operating Characteristics (continued +25°C, unless otherwise noted.) A MAX796 MAXIMUM SECONDARY CURRENT vs. SUPPLY VOLTAGE, 3.3V/5V CIRCUIT 1050 I (MAIN OUT 900 750 I (MAIN ...
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... Switching node (inductor) connection. Can swing 2V below ground without hazard. High-side gate-drive output. Normally drives the main buck switch floating driver output that swings 16 DH from LX to BST, riding on the LX switching-node voltage. Dual Mode is a trademark of Maxim Integrated Products. _______________________________________________________________________________________ Step-Down Controllers with FUNCTION = 100µA) if not used. ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ______Standard Application Circuit It is easy to adapt the basic MAX797 single-output 3.3V buck converter (Figure 1) to meet a wide range of applications with inputs up to 28V (limited by choice ...
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Synchronous Rectifier for CPU Power Table 1. Component Selection for Standard 3.3V Applications COMPONENT 1A Input Range 4.75V to 18V Application PDA Frequency 150kHz Q1 High-Side International Rectifier MOSFET 1/2 IRF7101 Q2 Low-Side International Rectifier MOSFET 1/2 IRF7101 C1 Input ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power BATTERY VOLTAGE 4.5V SECFB PWM LOGIC +2.505V REF COMPARATOR +2.505V AT 100µA REF GND 60kHz ON/OFF SHDN SS MAX796 SYNC Figure 2. MAX796 Block Diagram 12 ______________________________________________________________________________________ TO V+ CSL +5V LINEAR ...
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Synchronous Rectifier for CPU Power PWM Controller Blocks: • Multi-Input PWM Comparator • Current-Sense Circuit • PWM Logic Block • Dual-Mode Internal Feedback Mux • Gate-Driver Outputs • Secondary Feedback Comparator Bias Generator Blocks: • +5V Linear Regulator • Automatic ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power REF SLOPE COMP 30mV SKIP (MAX797 ONLY) 4µA SS 2.5V N SHDN –100mV REF (MAX796) GND (MAX799) SECFB NOTE 1 Figure 3. PWM Controller Detailed Block Diagram 14 ______________________________________________________________________________________ MAIN PWM COMPARATOR ...
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Synchronous Rectifier for CPU Power FB I1 REF CSH CSL SLOPE COMPENSATION Figure 4. Main PWM Comparator Block Diagram The output filter capacitor C2 sets a dominant pole in the feedback loop. This pole must roll off the loop gain ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power It’s often possible to achieve a bootstrap-like effect, even for circuits that are set to V < 4.5V, by powering VL OUT from an external-system +5V supply. To achieve this pseudo-bootstrap, add ...
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Synchronous Rectifier for CPU Power quency where harmonics of the switching frequency don’t overlap a sensitive frequency band. If necessary, synchronize the oscillator to a tight-tolerance external clock generator. The low-noise mode (SKIP = high) forces two changes upon the ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power V+ MAX874 DH MAX796 MAX797 DL MAX799 CSH CSL FB GND OUT REF REF2 REF Figure 7. Output Voltage Less than 2.5V MAX796), a 1µs ...
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Synchronous Rectifier for CPU Power _________________Design Procedure The five pre-designed standard application circuits (Figure 1 and Table 1) contain ready-to-use solutions for common applications. Use the following design pro- cedure to optimize the basic schematic for different voltage or current ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power Three key inductor parameters must be specified: inductance value (L), peak current (I resistance (R ). The following equation includes a DC constant LIR, which is the ratio of inductor peak-to- peak ...
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Synchronous Rectifier for CPU Power These equations are “worst-case” with 45 degrees of phase margin to ensure jitter-free fixed-frequency opera- tion and provide a nicely damped output response for zero to full-load step changes. Some cost-conscious designers may wish to ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ______Selecting Other Components MOSFET Switches The two high-current N-channel MOSFETs must be logic-level types with guaranteed on-resistance specifi- cations 4.5V. Lower gate threshold specs are GS better (i.e., 2V ...
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Synchronous Rectifier for CPU Power ____________Low-Voltage Operation Low input voltages and low input-output differential volt- ages each require some extra care in the design. Low absolute input voltages can cause the VL linear regulator to enter dropout, and eventually shut ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power sense resistor value. The R term assumes identi- DS(ON) cal MOSFETs for the high- and low-side switches because they time-share the inductor current. If the MOSFETs aren’t identical, their losses can be ...
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Synchronous Rectifier for CPU Power FAT, HIGH-CURRENT TRACES MAIN CURRENT PATH MAX796 MAX797 MAX799 Figure 10. Kelvin Connections for the Current-Sense Resistor _________________________________________________________Application Circuits 22µF, 35V SECFB ON/OFF SHDN BST LX MAX796 ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued) 33µF, 35V SECFB VL BST 6 ON/OFF SHDN DH MAX796 DL PGND 1 SS CSH CSL 0.01µF (OPTIONAL) GND REF SYNC 0.33µF ...
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Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued) Figure 14. 2.9V Low-Dropout Linear Regulator with Fast Transient Response V IN 2.5V TO 5.25V C1 100µF REF 0.33µF GND SKIP BST 4.7µF VL 33k 1N4148 0.01µF 1N4148 +3.3V (EXTERNAL) Figure 15. ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued) VIN 4.75V TO 6V CSH C1 220µF SYNC REF 0.33µF GND SKIP BST 4.7µF VL Figure 16. 5V-to-12V PWM Boost Converter INPUT CMPSH- 6.5V 100µF BST VL ...
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Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued) INPUT V+ SHDN SKIP MAX797 SS 0.01µF GND ––– OUT REF R2 ADJUST RANGE = 2. SHOWN. OMIT R2 FOR V ...
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Step-Down Controllers with Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued) INPUT 0.1µF V+ SHDN MAX797 SS 0.01µF SKIP GND Figure 20. Buck Converter with Low-Loss SMT Current-Sense Transformer INPUT 0.1µF 4.75V TO 5.5V V+ ON/OFF SHDN MAX797 SS C6 ...
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Synchronous Rectifier for CPU Power ____________________________________________Application Circuits (continued SHDN IN 10. 28V 22µF 35V MAX797 1 SS 0.01µF 5 SYNC FB GND 7 4 D1, D3 CENTRAL SEMI. CMPSH-3 D2 NIEC EC10QS02L, SCHOTTKY RECT. ...
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... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 32 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 2005 Maxim Integrated Products ___________________Chip Topography ...