Pinout
Specifications| Regulated LEDs | 7 |
| Total LED Current | 180 mA |
| Current Matching | 0.3% |
| Boost Type | Switched Capacitor Multi-Gain |
| Switching Frequency | 700 kHz |
| Efficiency (peak) | 87 % |
| Input Min Voltage | 2.7 Volt |
| Input Max Voltage | 5.5 Volt |
| Boost Voltage | Regulated |
| LED Configuration | Parallel |
| Supply Current | 1.3 mA |
| Switching Type | Fixed Freq |
| Special Features | Current regulated output, 3 sets of outputs are common cathode using current sink topology, control by an I2C compatible interface |
| PWM BrightCtrl | Yes |
| Analog-V BrightCtrl | No |
| Ambient Light Compensation | No |
| RGB-LED | No |
| Temperature Min | -30 deg C |
| Temperature Max | 85 deg C |
| RegType | WhiteLED Driver |
| PowerWise | No |
| View Using Catalog |
DescriptionThe LM27964 is a charge-pump-based white-LED driver that is ideal for mobile phone display backlighting. The LM27964 can drive up to 6 LEDs in parallel along with multiple keypad LEDs, with a total output current up to 180mA. Regulated internal current sources deliver excellent current matching in all LEDs.
The LED driver current sources are split into two independently controlled groups. The primary group (4 LEDs) can be used to backlight the main phone display and the second group (2 LEDs) can be used to backlight a secondary display. A single Keypad LED driver can power up to 16 keypad LEDs with a current of 5mA each. The LM27964 has an I 2C compatible interface that allows the user to independently control the brightness on each bank of LEDs.
The LM27964 works off an extended Li-Ion input voltage range (2.7V to 5.5V). The device provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in Pass-Mode. The proper gain for maintaining current regulation is chosen, based on LED forward voltage, so that efficiency is maximized over the input voltage range.
The LM27964 is available in National's small 24-pin Leadless Leadframe Package (LLP-24).
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
| LM27964SQ-C |
CMOS7 |
0 |
16561 |
0 |
0 |
954000 |
4 |
270700104 |
| LM27964SQ-I |
CMOS7 |
0 |
16561 |
0 |
0 |
954000 |
4 |
270700104 |
| LM27964SQX-C |
CMOS7 |
0 |
16561 |
0 |
0 |
954000 |
4 |
270700104 |
| LM27964SQX-I |
CMOS7 |
0 |
16561 |
0 |
0 |
954000 |
4 |
270700104 |
Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.For more information on Reliability Metrics, please click here.
More Application Notes
| Title |
Size in Kbytes |
Date |
|
| AN-1321: Application Note 1321 LM2796 Evaluation Board |
453 Kbytes |
25-May-04 |
Download |
| AN-1362: Application Note 1362 LM27961- Dual-Display White LED Driver with 3/2x Switched Capacitor Boost |
625 Kbytes |
30-Jun-05 |
Download |
AN-1362 (Chinese): Application Note 1362 LM27961- Dual-Display White LED Driver with 3/2x Switched Capacitor Boost
|
276 Kbytes |
|
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| AN-1582: Application Note 1582 LM27965 Dual Display White LED Driver with I2C Compatible Brightness Control |
1226 Kbytes |
18-Mar-07 |
Download |
AN-1582 (Chinese): Application Note 1582 LM27965 Dual Display White LED Driver with I2C Compatible Brightness Control
|
503 Kbytes |
|
640){this.height=this.height*640/this.width;this.width=640;}' border="0" alt=" Connection Diagram"> |
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LM27964 Data Sheet
