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MAX1644
2A, Low-Voltage, Step-Down Regulator with Synchronous Rectification and Internal Switches
Industry's Smallest 2A DC-DC with Synchronous Rectifier
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Status
Active: In Production.
Description
The MAX1644 constant-off-time, PWM step-down DC-DC converter is ideal for use in applications such as PC cards, CPU daughter cards, and desktop computer bus-termination boards. The device features internal synchronous rectification for high efficiency and reduced component count. It requires no external Schottky diode. The internal 0.10Ω PMOS power switch and 0.10Ω NMOS synchronous-rectifier switch easily deliver continuous load currents up to 2A. The MAX1644 produces a preset +3.3V or +2.5V output voltage or an adjustable output from +1.1V to VIN. It achieves efficiencies as high as 95%.
The MAX1644 uses a unique current-mode, constant-off-time, PWM control scheme, which includes an Idle Mode™ to maintain high efficiency during light-load operation. The programmable constant-off-time architecture sets switching frequencies up to 350kHz, allowing the user to optimize performance trade-offs between efficiency, output switching noise, component size, and cost. The device also features an adjustable soft-start to limit surge currents during start-up, a 100% duty cycle mode for low-dropout operation, and a low-power shutdown mode that disconnects the input from the output and reduces supply current below 1µA. The MAX1644 is available in a 16-pin SSOP package.
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Data Sheet
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An evaluation kit is available: MAX1644EVKIT
Key Features
- ±1% Output Accuracy
- 95% Efficiency
- Internal PMOS and NMOS Switches
- 70mΩ On-Resistance at VIN = +4.5V
- 100mΩ On-Resistance at VIN = +3V
- Output Voltage
- +3.3V or +2.5V Pin-Selectable
- +1.1V to VIN Adjustable
- +3V to +5.5V Input Voltage Range
- 360µA (max) Operating Supply Current
- < 1µA Shutdown Supply Current
- Programmable Constant-Off-Time Operation
- 350kHz (max) Switching Frequency
- Idle Mode Operation at Light Loads
- Thermal Shutdown
- Adjustable Soft-Start Inrush Current Limiting
- 100% Duty Cycle During Low-Dropout Operation
- Output Short-Circuit Protection
- 16-Pin SSOP Package
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Applications/Uses
- +3.3V PC Card and CardBus Applications
- +5V to +3.3V/+2.5V Conversion
- CPU Daughter Card Supply
- CPU I/O Supplies
- Desktop Bus-Termination Boards
- Notebook and Subnotebook Computers
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Key Specifications:
| Step-Down Switching Regulators |
| Part Number |
VIN
(V) |
VIN
(V) |
VOUT
(V) |
VOUT
(V) |
Preset 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 |
| MAX1644 |
3 |
5.5 |
1.1 |
5.5 |
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2 |
2 |
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1 |
350 |
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50 |
$4.38 @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
Application Notes
Reliability Reports
Software/Models
Ordering Information
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Part Number
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Free
Sample |
Buy |
Status
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Package:
TYPE PINS FOOTPRINT
DRAWING CODE/VAR *
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Temp |
RoHS/Lead-Free?
Materials Analysis
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| MAX1644EAE
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16-2*
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-40°C to +85°C
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See data sheet
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| MAX1644EAE+
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16+2*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1644EAE+T
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16+2*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1644EAE-T
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16-2*
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-40°C to +85°C
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See data sheet
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| MAX1644EAE/GH9
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16-2*
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-40°C to +85°C
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See data sheet
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| MAX1644EAE/GH9-T
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Active |
SSOP;16 pin;50 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0106 (PDF)
Use pkgcode/variation: A16-2*
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-40°C to +85°C
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See data sheet
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Notes:
- Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
- Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
- Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
- * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.
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Notes and Comments
No external Schottky required. Integrated, lossless current-sense eliminates external current sense resistor. Space saving SSOP package.
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More Information
Didn't Find What You Need?
Information Index
Document Ref.: 19-1457
Rev 3;
2005-10-10
This page last modified: 2007-07-23
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