MAX849
1-Cell-to-3-Cell, High-Power, Low-Noise, Step-Up DC-DC Converters
Integrated 2-Channel ADC Allows Accurate Battery Voltage Monitoring
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Overview
Features and Benefits
- Up to 95% Efficiency
- 3.3V Dual Mode™ or 2.7V to 5.5V Adj. Output
- 0.7V to 5.5V Input Range
- 0.15mW Standby Mode
- 300kHz PWM Mode or Synchronizable
- Two-Channel ADC with Serial Output
- Power-Good Function
Product Details
The MAX848/MAX849 boost converters set a new standard of high efficiency and high integration for noise-sensitive power-supply applications, such as portable phones and small systems with RF data links. The heart of the these devices is a synchronous boost-topology regulator that generates a fixed 3.3V output (or 2.7V to 5.5V adjustable output) from one to three NiCd/NiMH cells or one Li-Ion cell.
Synchronous rectification provides a 5% efficiency improvement over similar nonsynchronous boost regulators. In standby mode, pulse-skipping PFM operation keeps the output voltage alive with only 150µW quiescent power consumption. Fixed-frequency PWM operation ensures that the switching noise spectrum is limited to the 300kHz fundamental and its harmonics, allowing easy post-filtering noise reduction. For even tighter noise spectrum control, synchronize to a 200kHz to 400kHz external clock.
Battery monitoring is provided by a two-channel, voltage-to-frequency analog-to-digital converter (ADC). One channel is intended for a single-cell battery input (0.625V to 1.875V range), while the other channel is for monitoring higher voltages (0V to 2.5V range).
Two control inputs are provided for push-on, push-off control via a momentary pushbutton switch. Upon power-up, an internal comparator monitors the output voltage to generate a power-good output (POK).
The devices differ only in the current limit of the N-channel MOSFET power switch: 0.8A for the MAX848, and 1.4A for the MAX849.
Applications
- Cell Phones
- Digital Cordless Phones
- Handheld Instruments (PDAs, Palmtops)
- Local 3.3V to 5V Supplies
- Palmtop Computers
- PCS Phones
- Personal Communicators
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Documentation & Resources
Product Recommendations
MAX849 Companion Parts
Recommended Related Parts
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
| Part Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| MAX849ESE+ | Material Declaration | Reliability Data | Small-Outline IC, Narrow (0.15in) | |
| MAX849ESE+T | Material Declaration | Reliability Data | Small-Outline IC, Narrow (0.15in) | |
| Wafer Fabrication Data |
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