|
|
|
MAX8744, MAX8745
High-Efficiency, Quad Output, Main Power-Supply Controllers for Notebook Computers
|
Status
Active: In Production.
Description
The MAX8744/MAX8745 are dual step-down, switch-mode, power-supply (SMPS) controllers with synchronous rectification, intended for main 5V/3.3V power
generation in battery-powered systems. Fixed-frequency operation with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.3V before duty-cycle overlap occurs, compared to 180° out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V.
Output current sensing provides peak current-limit protection, using either an accurate sense resistor or using lossless inductor DCR current sensing. A low-noise mode maintains high light-load efficiency while keeping the switching frequency out of the audible range.
An internal, fixed 5V, 100mA linear regulator powers up the MAX8744/MAX8745 and their gate drivers, as well as external keep-alive loads. When the main PWM regulator is in regulation, an automatic bootstrap switch bypasses the internal linear regulator, providing current up to 200mA. An additional adjustable linear-regulator driver with an external pnp transistor may be used with a secondary winding to provide a 12V supply, or powered directly from the main outputs to generate low-voltage outputs as low as 1V.
Independent enable controls and power-good signals allow flexible power sequencing. Voltage soft-start gradually ramps up the output voltage and reduces
inrush current, while soft-shutdown gradually ramps the output voltage down, preventing negative voltage dips. The MAX8744/MAX8745 feature output undervoltage and thermal-fault protection. The MAX8744 also includes output overvoltage-fault protection.
The MAX8744/MAX8745 are available in a 32-pin, 5mm x 5mm, thin QFN package. The exposed backside pad improves thermal characteristics for demanding linear
keep-alive applications.
|
|
Data Sheet
|
Key Features
- Fixed-Frequency, Current-Mode Control
- 40/60 Optimal Interleaving
- Internal BST Switches
- Internal 5V, 100mA Linear Regulator
- Auxiliary Linear-Regulator Driver (12V or Adjustable Down to 1V)
- Dual Mode™ Feedback—3.3V/5V Fixed or Adjustable Output Voltages
- 200kHz/300kHz/500kHz Switching Frequency
- Undervoltage and Thermal-Fault Protection
- Overvoltage-Fault Protection (MAX8744 Only)
- 6V to 26V Input Range
- 2V ±0.75% Reference Output
- Independent Enable Inputs and Power-Good Outputs
- Soft-Start and Soft-Shutdown (Voltage Ramp)
- 8µA (typ) Shutdown Current
|
|
Applications/Uses
- 2 to 4 Li+ Cell Battery-Powered Devices
- Main Power Supplies
- Notebook and Subnotebook Computers
- PDAs and Mobile Communicators
|
|
|
|
Diagram
Functional Diagram
Reliability Reports
| Show FIT data for: |
|
| Request Reliability Report for: |
|
Software/Models
Ordering Information
|
Part Number
|
Free
Sample |
Buy |
Status
|
Package:
TYPE PINS FOOTPRINT
DRAWING CODE/VAR *
|
Temp |
RoHS/Lead-Free?
Materials Analysis
|
| MAX8744ETJ+
|
|
|
Active |
TQFN;32 pin;26 mm²
Outline Drawing:21-0140 (PDF)
Land Pattern: 90-0012 (PDF)
Use pkgcode/variation: T3255+4*
|
-40°C to +85°C
|
RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX8744ETJ+T
|
|
|
Active |
TQFN;32 pin;26 mm²
Outline Drawing:21-0140 (PDF)
Land Pattern: 90-0012 (PDF)
Use pkgcode/variation: T3255+4*
|
-40°C to +85°C
|
RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX8745ETJ+
|
|
|
Active |
TQFN;32 pin;26 mm²
Outline Drawing:21-0140 (PDF)
Land Pattern: 90-0012 (PDF)
Use pkgcode/variation: T3255+4*
|
-40°C to +85°C
|
RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX8745ETJ+T
|
|
|
Active |
QFN;32 pin
Land Pattern: Not Available
|
-40°C to +85°C
|
See data sheet
|
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.
|
Similar Products by Function
| MAX1630, MAX1631, MAX1632, ... |
Multi Output, Low-Noise Power Supply Controllers for Notebook Computers |
| MAX1901, MAX1902, MAX1904 |
500kHz Multi-Output, Low-Noise Power-Supply Controllers for Notebook Computers |
| MAX1777, MAX1977, MAX1999 |
High-Efficiency, Quad Output, Main Power-Supply Controllers for Notebook Computers |
| MAX1533, MAX1537 |
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers |
Products with Similar Part Numbers
Didn't Find What You Need?
Information Index
Document Ref.: 19-3796
Rev 0;
2006-04-19
This page last modified: 2009-08-11
|
|
|
Download
E-Mail