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MAX887, MAX887H
100% Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter
Internal Power MOSFET and Current-Sense Reduces Component Count and Saves Space
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Status
Active: In Production.
Description
The MAX887 high-efficiency, step-down DC-DC converter provides an adjustable output from 1.25V to 10.5V. It accepts inputs from 3.5V to 11V and delivers 600mA. Operation to 100% duty cycle minimizes dropout voltage (300mV typ at 500mA). Synchronous rectification reduces output rectifier losses, resulting in efficiency as high as 95%.
Fixed-frequency pulse-width modulation (PWM) reduces noise in sensitive communications applications. Using a high-frequency internal oscillator allows tiny surface-mount components to reduce PC board area, and eliminates audio-frequency interference. A SYNC input allows synchronization to an external clock to avoid interference with sensitive RF and data-acquisition circuits.
The MAX887 features current-mode operation for superior load/line-transient response. Cycle-by-cycle current limiting protects the internal MOSFET and rectifier. A low-current (2.5µA typ) shutdown mode conserves battery life.
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Data Sheet
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An evaluation kit is available: MAX887EVKIT
Key Features
- 95% Efficiency
- 600mA Output Current
- Cycle-by-Cycle Current Limiting
- Low-Dropout, 100% Duty-Cycle Operation, 300mV at 500mA
- Internal 0.6Ω (typ) MOSFET
- Internal Synchronous Rectifier
- High-Frequency Current-Mode PWM
- External SYNC or Internal 300kHz Oscillator
- Guaranteed 260kHz to 340kHz Internal Oscillator Frequency Limits
- 2.5µA Shutdown Mode
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Applications/Uses
- Cell Phones
- Computer Peripherals
- Distributed Power Systems
- Personal Communicators
- Portable Instrumentation
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Key Specifications:
| Step-Down Switching Regulators |
| Part Number |
VIN
(V) |
VIN
(V) |
VOUT
(V) |
VOUT
(V) |
Max. IOUT
(A) |
Max. IOUT
(A) |
Output Adjust. Method |
DC-DC Outputs |
Oper. Freq.
(kHz) |
Package/Pins |
Smallest Available Pckg.
(mm2) |
Budgetary Price |
| min |
max |
min |
max |
≥ |
≤ |
max w/pins |
See Notes |
| MAX887 |
3.5 |
11 |
1.25 |
10 |
0.6 |
0.6 |
Resistor |
1 |
440 |
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30.9 |
$2.73 @1k |
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See All Step-Down Switching Regulators (282)
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Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
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Diagram
 Typical Operating Circuit
Notes and Comments
2.5 µA shutdown mode, internal synchronous rectifier, 600mA output current
Didn't Find What You Need?
Information Index
Document Ref.: 19-1142
Rev 0;
1996-09-01
This page last modified: 2007-05-31
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