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MAX1575
White LED 1x/1.5x Charge Pump for Main and Sub-Displays
First 85% Efficient, Fractional, White-LED Charge Pump with Dual, Single-Wire Dimming Control for Main and Sub-Displays
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Status
Active: In Production.
Description
The MAX1575 charge pump drives up to four white LEDs in the main display and up to two white LEDs in the sub-display with regulated constant current for uniform intensity. By utilizing adaptive 1x/1.5x charge-pump modes and very-low-dropout current regulators, it achieves high efficiency over the full 1-cell lithium-battery input voltage range. A 1MHz fixed-frequency switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple.
The MAX1575 uses an external resistor to set the full-scale 100% LED current. Two enable inputs, ENM and ENS, are used for simple on/off controls for the main and sub-displays, respectively. By repeatedly pulsing either enable input, the LEDs can be dimmed in multiple steps down to 5%. Once the desired brightness is set, the MAX1575 maintains that brightness setting as long as the enable input is kept high. If an enable input is kept low for more than 2ms, the LED current for the respective display is set to zero. If both enable inputs are kept low for more than 2ms, the MAX1575 enters shutdown.
The MAX1575 is available in a 16-pin 4mm x 4mm thin QFN package (0.8mm max height).
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Data Sheet
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An evaluation kit is available: MAX1575EVKIT
Key Features
- Powers Main and Sub-Display LEDs
- 85% Average Efficiency (PLED / PBATT) Over Li+ Battery Discharge
- 2% LED Current Matching
- Up to 30mA/LED Drive Capability
- Adaptive 1x/1.5x Mode Switchover
- Low Input Ripple and EMI
- Individual 5% to 100% Dimming Through Single-Wire Serial Pulse Interface
- Low 0.1µA Shutdown Current
- 2.7V to 5.5V Supply Voltage Range
- Soft-Start Limits Inrush Current
- Output-Overvoltage Protection
- Thermal-Shutdown Protection
- 16-Pin Thin QFN 4mm x 4mm Package
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Applications/Uses
- Cell Phones with Main and Sub-Displays
- PDAs/Smartphones with Up to Six White LEDs
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Key Specifications:
| White LED Drivers |
| Part Number |
Topology |
LEDs |
Config. |
Dimming Control |
POUT
(W) |
ILED
(mA) |
VIN
(V) |
VIN
(V) |
ICC
(mA) |
VOUT
(V) |
Oper. Freq.
(kHz) |
Package/Pins |
Budgetary Price |
| max num. of |
max |
min |
max |
max |
max |
See Notes |
| MAX1575 |
Charge Pump |
6 |
Parallel |
Serial Pulse |
0.75 |
30 |
2.7 |
5.5 |
2 |
5 |
1000 |
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$1.93 @1k |
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See All White LED Drivers (47)
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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
Product Guides
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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| MAX1575ETE
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Active |
TQFN;16 pin;16.8 mm²
Outline Drawing:21-0139 (PDF)
Land Pattern: 90-0070 (PDF)
Use pkgcode/variation: T1644-4*
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-40°C to +85°C
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RoHS/Lead-Free: No
Materials Analysis |
| MAX1575ETE+
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Active |
TQFN;16 pin;16.8 mm²
Outline Drawing:21-0139 (PDF)
Land Pattern: 90-0070 (PDF)
Use pkgcode/variation: T1644+4*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1575ETE+T
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Active |
TQFN;16 pin;16.8 mm²
Outline Drawing:21-0139 (PDF)
Land Pattern: 90-0070 (PDF)
Use pkgcode/variation: T1644+4*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1575ETE-T
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Active |
QFN;16 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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| MAX1575ETE/V+
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Active |
TQFN;16 pin;16.8 mm²
Outline Drawing:21-0139 (PDF)
Land Pattern: 90-0070 (PDF)
Use pkgcode/variation: T1644+4*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1575ETE/V+T
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Active |
QFN;
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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Information Index
Document Ref.: 19-3097
Rev 2;
2005-09-14
This page last modified: 2009-10-08
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