Datasheet MAX1836, MAX1837 (Maxim) - 7
| Fabricante | Maxim |
| Descripción | 24V Internal Switch, 100% Duty Cycle, Step-Down Converters |
| Páginas / Página | 15 / 7 — Pin Description. PIN. NAME. FUNCTION. MAX1836. MAX1837. NOTE:. Detailed … |
| Formato / tamaño de archivo | PDF / 2.1 Mb |
| Idioma del documento | Inglés |
Pin Description. PIN. NAME. FUNCTION. MAX1836. MAX1837. NOTE:. Detailed Description. Current-Limited Control Architecture
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MAX1836/MAX1837 24V Internal Switch, 100% Duty Cycle, Step-Down Converters
Pin Description PIN NAME FUNCTION
Dual-Mode Feedback Input. Connect to GND for the preset 3.3V (MAX183_EUT33) or 5.0V (MAX183_ 1 FB EUT50) output. Connect to a resistive divider between the output and FB to adjust the output voltage between 1.25V and VIN, and connect the OUT pin to GND. When setting output voltages above 5.5V, permanently connect SHDN to IN. 2 GND Ground 3 IN Input Voltage. 4.5V to 24V input range. Connected to the internal p-channel power MOSFET’s source. 4 LX Inductor Connection. Connected to the internal p-channel power MOSFET’s drain. Shutdown Input. A logic-low shuts down the MAX1836/MAX1837 and reduces supply current to 3µA. LX is 5 SHDN high impedance in shutdown. Connect to IN for normal operation. When setting output voltages above 5.5V, permanently connect SHDN to IN. Regulated Output Voltage High-Impedance Sense Input. Internally connected to a resistive divider. Connect to 6 OUT the output when using the preset output voltage. Connect to GND when using an external resistive divider to adjust the output voltage. — EP Exposed Metal Pad. Connect to GND. This pad is internally connected to GND through a soft connect. For proper grounding and good thermal dissipation. Connect the exposed pad to GND. INPUT L1 OUTPUT INPUT L1 OUTPUT 4.5V OR 12V 47µH 3.3V OR 5V 4.5V OR 12V 22µH 3.3V OR 5V IN LX IN LX CIN D1 COUT CIN D1 COUT 10µF SHDN 100µF SHDN 10µF 150µF 25V
MAX1836
6.3V 25V
MAX1837
6.3V OUT OUT GND FB GND FB CIN = TAIYO YUDEN TMK432BJ106KM CIN = TAIYO YUDEN TMK432BJ106KM L1 = SUMIDA CDRH5D28-470 L1 = SUMIDA CDRH5D28-220 COUT = SANYO POSCAP 6TPC100M (SMALLER CAPACITORS CAN BE USED FOR 5V) COUT = SANYO OS-CON 6SA150M (SMALLER CAPACITORS CAN BE USED FOR 5V) D1 = NIHON EP05Q03L D1 = NIHON ED05Q03L
NOTE:
HIGH-CURRENT PATHS SHOWN WITH BOLD LINES.
NOTE:
HIGH-CURRENT PATHS SHOWN WITH BOLD LINES. Figure 1. Typical MAX1836 Application Circuit Figure 2. Typical MAX1837 Application Circuit
Detailed Description
high switching frequency minimize PC board space and The MAX1836/MAX1837 step-down converters are component cost. designed primarily for battery-powered devices, notebook
Current-Limited Control Architecture
computers, and industrial control applications. A unique The MAX1836/MAX1837 use a proprietary current-limited current-limited control scheme provides high efficiency control scheme that operates with duty cycles up to 100%. over a wide load range. Operation up to 100% duty cycle These DC-DC converters pulse as needed to maintain allows the lowest possible dropout voltage, increasing regulation, resulting in a variable switching frequency that the useable supply voltage range. Under no-load, the increases with the load. This eliminates the high supply MAX1836/MAX1837 draw only 12μA, and in shutdown currents associated with conventional constant-frequency mode, they draw only 3μA to further reduce power con- pulse-width-modulation (PWM) controllers that switch the sumption and extend battery life. Additionally, an internal MOSFET unnecessarily. 24V switching MOSFET, internal current sensing, and a www.maximintegrated.com Maxim Integrated │ 7
Pin Description PIN NAME FUNCTION
Dual-Mode Feedback Input. Connect to GND for the preset 3.3V (MAX183_EUT33) or 5.0V (MAX183_ 1 FB EUT50) output. Connect to a resistive divider between the output and FB to adjust the output voltage between 1.25V and VIN, and connect the OUT pin to GND. When setting output voltages above 5.5V, permanently connect SHDN to IN. 2 GND Ground 3 IN Input Voltage. 4.5V to 24V input range. Connected to the internal p-channel power MOSFET’s source. 4 LX Inductor Connection. Connected to the internal p-channel power MOSFET’s drain. Shutdown Input. A logic-low shuts down the MAX1836/MAX1837 and reduces supply current to 3µA. LX is 5 SHDN high impedance in shutdown. Connect to IN for normal operation. When setting output voltages above 5.5V, permanently connect SHDN to IN. Regulated Output Voltage High-Impedance Sense Input. Internally connected to a resistive divider. Connect to 6 OUT the output when using the preset output voltage. Connect to GND when using an external resistive divider to adjust the output voltage. — EP Exposed Metal Pad. Connect to GND. This pad is internally connected to GND through a soft connect. For proper grounding and good thermal dissipation. Connect the exposed pad to GND. INPUT L1 OUTPUT INPUT L1 OUTPUT 4.5V OR 12V 47µH 3.3V OR 5V 4.5V OR 12V 22µH 3.3V OR 5V IN LX IN LX CIN D1 COUT CIN D1 COUT 10µF SHDN 100µF SHDN 10µF 150µF 25V
MAX1836
6.3V 25V
MAX1837
6.3V OUT OUT GND FB GND FB CIN = TAIYO YUDEN TMK432BJ106KM CIN = TAIYO YUDEN TMK432BJ106KM L1 = SUMIDA CDRH5D28-470 L1 = SUMIDA CDRH5D28-220 COUT = SANYO POSCAP 6TPC100M (SMALLER CAPACITORS CAN BE USED FOR 5V) COUT = SANYO OS-CON 6SA150M (SMALLER CAPACITORS CAN BE USED FOR 5V) D1 = NIHON EP05Q03L D1 = NIHON ED05Q03L
NOTE:
HIGH-CURRENT PATHS SHOWN WITH BOLD LINES.
NOTE:
HIGH-CURRENT PATHS SHOWN WITH BOLD LINES. Figure 1. Typical MAX1836 Application Circuit Figure 2. Typical MAX1837 Application Circuit
Detailed Description
high switching frequency minimize PC board space and The MAX1836/MAX1837 step-down converters are component cost. designed primarily for battery-powered devices, notebook
Current-Limited Control Architecture
computers, and industrial control applications. A unique The MAX1836/MAX1837 use a proprietary current-limited current-limited control scheme provides high efficiency control scheme that operates with duty cycles up to 100%. over a wide load range. Operation up to 100% duty cycle These DC-DC converters pulse as needed to maintain allows the lowest possible dropout voltage, increasing regulation, resulting in a variable switching frequency that the useable supply voltage range. Under no-load, the increases with the load. This eliminates the high supply MAX1836/MAX1837 draw only 12μA, and in shutdown currents associated with conventional constant-frequency mode, they draw only 3μA to further reduce power con- pulse-width-modulation (PWM) controllers that switch the sumption and extend battery life. Additionally, an internal MOSFET unnecessarily. 24V switching MOSFET, internal current sensing, and a www.maximintegrated.com Maxim Integrated │ 7