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MAX1549
Dual, Interleaved, Fixed-Frequency Step-Down Controller with a Dynamically Adjustable Output
Dual, Interleaved, Fixed-Frequency Step-Down Controller with a Dynamically Adjustable Output Designed for Generation of Low-Voltage Chipset and RAM Power Supplies in Notebook Computers
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Status
All versions are No Longer Available.
Description
The MAX1549 dual pulse-width modulation (PWM) stepdown
controller provides the high efficiency, excellent
transient response, and high DC-output accuracy necessary
for generating low-voltage chipset and RAM
power supplies in notebook computers. The controller
employs a fixed-frequency, current-mode PWM architecture
that does not require complex compensation.
The MAX1549 also interleaves the dual step-down regulators,
minimizing the input capacitor requirements.
The MAX1549 features differential current-sense inputs
for accurately sensing the inductor current across an
external current-sense resistor in series with the output
to ensure reliable overload protection. Alternatively, the
controller can provide overload protection using lossless
inductor current-sensing methods, lowering power
dissipation and reducing system cost.
Single-stage buck conversion allows the MAX1549 to
directly step down high-voltage batteries for the highest
possible efficiency. Very low output-voltage applications
require two-stage conversion—stepping down
from another system supply rail instead of the battery.
The MAX1549 powers chipsets and graphics processor
cores that require dynamically adjustable output voltages,
or generates the active termination bus that must track
the input reference. The main step-down controller
(OUT1) regulates the dedicated reference input (REFIN)
voltage generated by a resistive voltage-divider from the
MAX1549's reference. The MAX1549 also includes internal
open-drain pulldowns with logic-level control inputs to
dynamically adjust the REFIN resistive-divider ratio. When
a transition occurs on these control inputs, the controller
enters forced-PWM mode and blanks the power-good
(PGOOD1) output and output fault protection. OUT2 uses
a Dual-Mode™ feedback input to provide either fixed
2.5V/1.8V or adjustable output voltage regulation. The
MAX1549 is available in a 40-pin, 6mm x 6mm thin QFN
package.
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Data Sheet
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Key Features
- Interleaved, Fixed-Frequency, Current-Mode Control Architecture
- 1% VOUT Accuracy Over Line and Load
- Main Output (OUT1)
- 0.5V to 2.0V Adjustable Output
- External Reference Input for Dynamically Selectable Output Voltages
- Four Digitally Selectable Output Voltages
- Power-Good and Fault Blanking During Transitions
- Second Output (OUT2)
- 2.5V/1.8V Fixed or 0.5V to 2.7V Adjustable Output
- Accurate Differential Current-Sense Inputs
- 100kHz/200kHz/300kHz/400kHz Selectable Switching Frequency
- Output Overvoltage/Undervoltage Protection
- Soft-Start and Soft-Shutdown
- Drives Large Synchronous-Rectifier FETs
- 2V ±0.6% Reference Output
- Separate Enable Inputs with Accurate Threshold Voltages
- Separate Power-Good Window Comparators
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Applications/Uses
- Active Termination Buses
- CPU Core or VCC Supplies
- DDR Memory Termination
- Dynamically Adjustable Chipset Supplies
- Fixed Chipset/RAM Supplies
- Notebook Computers
- Video/GPU Core Supplies
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Diagram
Pin Configuration
Reliability Reports
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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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| MAX1549ETL
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N/A |
No Longer Available |
TQFN;40 pin;37.2 mm²
Outline Drawing:21-0141 (PDF)
Land Pattern: 90-0055 (PDF)
Use pkgcode/variation: T4066-5*
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-40°C to +85°C
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RoHS/Lead-Free: No
Materials Analysis |
| MAX1549ETL+
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N/A |
No Longer Available |
TQFN;40 pin;37.2 mm²
Outline Drawing:21-0141 (PDF)
Land Pattern: 90-0055 (PDF)
Use pkgcode/variation: T4066+5*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1549ETL+T
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N/A |
No Longer Available |
TQFN;40 pin;37.2 mm²
Outline Drawing:21-0141 (PDF)
Land Pattern: 90-0055 (PDF)
Use pkgcode/variation: T4066+5*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1549ETL-T
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N/A |
No Longer Available |
QFN;40 pin
Land Pattern: Not Available
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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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More Information
Didn't Find What You Need?
Information Index
Document Ref.: 19-3165
Rev 1;
2006-06-15
This page last modified: 2009-10-12
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