General Description
The MAX1992/MAX1993 pulse-width modulation (PWM) controllers provide high-efficiency, excellent transient response, and high DC output accuracy. The devices step down high-voltage batteries to generate low voltage CPU core or chipset/RAM supplies in notebook
computers. Maxim’s proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients, while maintaining a relatively constant switching frequency. Efficiency is enhanced by the ability to drive very large synchronous rectifier MOSFETs. Current sensing to ensure reliable overload and inductor saturation protection is available using an external current-sense resistor in series with the
output. Alternatively, the controller can sense the current across the synchronous rectifier alone or use lossless inductor sensing for lowest power dissipation. Single-stage buck conversion allows the MAX1992/
MAX1993 to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down from another system supply rail instead of the battery) at the maximum switching frequency allows the minimum possible physical size.
The MAX1992 powers the CPU core, chipset, DRAM, or other supply rails as low as 0.7V. The MAX1993 powers chipsets and graphics processor cores, which require dynamically adjustable output voltages. The MAX1993 provides a tracking input that can be used for active termination buses. The MAX1992/MAX1993 are available in a 24-pin thin QFN package with optional over voltage and undervoltage protection.
For dual step-down PWM controllers with inductor saturation protection, external reference input voltage, and dynamically selectable output voltages, refer to the MAX1540/MAX1541 data sheet.
Features
- Inductor Saturation Protection Accurate Current Limit Ultra-High Efficiency Quick-PWM with 100ns Load-Step Response MAX1992 1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable Output Range
MAX1993 External Reference Input Dynamically Selectable Output Voltage (0.7V to 5.5V)
Optional Power-Good and Fault Blanking During Transitions ±1% VOUT Accuracy Over Line and Load
2V to 28V Battery Input Range (VIN) 200/300/450/600kHz Switching Frequency Overvoltage/Undervoltage Protection Option 1.7ms Digital Soft-Start Drives Large Synchronous Rectifier FETs 2V ±0.7% Reference Output Power-Good Window Comparator
Applications
- Notebook Computers
- Core/IO Supplies as Low as 0.7V
- 1.8V and 2.5V Supplies
- DDR Memory Termination (MAX1993)
- Active Termination Buses (MAX1993) CPU/Chipset/GPU with Dynamic Voltage Cores (MAX1993).
Battery Charger Controller ISL6251, ISL6251A
The MAX1992/MAX1993 pulse-width modulation (PWM) controllers provide high-efficiency, excellent transient response, and high DC output accuracy. The devices step down high-voltage batteries to generate low voltage CPU core or chipset/RAM supplies in notebook
computers. Maxim’s proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients, while maintaining a relatively constant switching frequency. Efficiency is enhanced by the ability to drive very large synchronous rectifier MOSFETs. Current sensing to ensure reliable overload and inductor saturation protection is available using an external current-sense resistor in series with the
output. Alternatively, the controller can sense the current across the synchronous rectifier alone or use lossless inductor sensing for lowest power dissipation. Single-stage buck conversion allows the MAX1992/
MAX1993 to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down from another system supply rail instead of the battery) at the maximum switching frequency allows the minimum possible physical size.
The MAX1992 powers the CPU core, chipset, DRAM, or other supply rails as low as 0.7V. The MAX1993 powers chipsets and graphics processor cores, which require dynamically adjustable output voltages. The MAX1993 provides a tracking input that can be used for active termination buses. The MAX1992/MAX1993 are available in a 24-pin thin QFN package with optional over voltage and undervoltage protection.
For dual step-down PWM controllers with inductor saturation protection, external reference input voltage, and dynamically selectable output voltages, refer to the MAX1540/MAX1541 data sheet.
Features
- Inductor Saturation Protection Accurate Current Limit Ultra-High Efficiency Quick-PWM with 100ns Load-Step Response MAX1992 1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable Output Range
MAX1993 External Reference Input Dynamically Selectable Output Voltage (0.7V to 5.5V)
Optional Power-Good and Fault Blanking During Transitions ±1% VOUT Accuracy Over Line and Load
2V to 28V Battery Input Range (VIN) 200/300/450/600kHz Switching Frequency Overvoltage/Undervoltage Protection Option 1.7ms Digital Soft-Start Drives Large Synchronous Rectifier FETs 2V ±0.7% Reference Output Power-Good Window Comparator
Applications
- Notebook Computers
- Core/IO Supplies as Low as 0.7V
- 1.8V and 2.5V Supplies
- DDR Memory Termination (MAX1993)
- Active Termination Buses (MAX1993) CPU/Chipset/GPU with Dynamic Voltage Cores (MAX1993).
Battery Charger Controller ISL6251, ISL6251A
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