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MAX8545, MAX8546, MAX8548
Low-Cost, Wide Input Range, Step-Down Controllers with Foldback Current Limit
2.7V to 28V Input, 15A, Step-Down, DC-DC Controllers for Desktop and Graphic Card Supplies have Foldback Current Protection
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Status
Active: In Production.
Description
The MAX8545/MAX8546/MAX8548 are voltage-mode pulse-width-modulated (PWM), step-down DC-DC controllers ideal for a variety of cost-sensitive applications.
They drive low-cost n-channel MOSFETs for both the high-side switch and synchronous rectifier, and require no external current-sense resistor. These devices can supply output voltages as low as 0.8V.
The MAX8545/MAX8546/MAX8548 have a wide 2.7V to 28V input range, and do not need any additional bias voltage. The output voltage can be precisely regulated
from 0.8V to 0.83 x VIN. These devices can provide efficiency
up to 95%. Lossless short-circuit and current-limit protection is provided by monitoring the RDS(ON) of the low-side MOSFET. The MAX8545 and MAX8548 have a current-limit threshold of 320mV, while the MAX8546 has a current-limit threshold of 165mV. All devices feature foldback-current capability to minimize power dissipation under short-circuit condition. Pulling the COMP/EN pin low with an open-collector or low-capacitance, open-drain
device can shut down all devices.
The MAX8545/MAX8546 operate at 300kHz and the MAX8548 operates at 100kHz. The MAX8545/MAX8546/MAX8548 are compatible with low-cost aluminum electrolytic capacitors. Input undervoltage lockout prevents proper operation under power-sag operations to prevent external MOSFETs from overheating. Internal soft-start is included to reduce inrush current. These devices are offered in space-saving 10-pin µMAX® packages.
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Data Sheet
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An evaluation kit is available: MAX8546EVKIT
Key Features
- 2.7V to 28V Input Range
- Foldback Short-Circuit Protection
- No Additional Bias Supply Needed
- 0.8V to 0.83 x VIN Output
- Up to 95% Efficiency
- Low-Cost External Components
- No Current-Sense Resistor
- All n-Channel MOSFET Design
- Adaptive Gate Drivers Eliminate Shoot-Through
- Lossless Overcurrent and Short-Circuit Protection
- 300kHz Switching Frequency (MAX8545/MAX8546)
- 100kHz Switching Frequency (MAX8548)
- Pin-Compatible with the MAX1967
- Thermal Shutdown
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Applications/Uses
- Cable Modems and Routers
- Desktops and Desknotes
- Graphic Card and Video Supplies
- Networking Power Supplies
- Notebook Docking Station Supplies
- PCI Express® Power Supplies
- Set-Top Boxes
- Telecom Power Supplies
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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 |
| MAX8545 |
2.7 |
28 |
0.8 |
23 |
15 |
15 |
Resistor |
1 |
300 |
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15.4 |
$1.10 @1k |
| MAX8546 |
300 |
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$1.10 @1k |
| MAX8548 |
100 |
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$1.08 @1k |
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See All Step-Down Switching Regulators (284)
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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
More Information
Didn't Find What You Need?
Information Index
Document Ref.: 19-2795
Rev 2;
2007-07-20
This page last modified: 2009-10-13
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