LM3530UME-40/NOPB National Semiconductor, LM3530UME-40/NOPB Datasheet - Page 25

• Manufacturer Part Number: LM3530UME-40/NOPB
• Description: IC LED DRVR PROGRAM I2C 12USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3530UME-40/NOPB

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 500kHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 12-UFBGA
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: Adjustable
• Led Driver Application: LED Backlighting, Portable Electronics
• No. Of Outputs: 1
• Output Current: 29.5mA
• Output Voltage: 40V
• Input Voltage: 2.7V To 5.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Other names: LM3530UME-40TR

INTERRUPT OUTPUT
INT is an open-drain output which pulls low when the Ambient
Light Sensing circuit has transitioned to a new ambient bright-
ness zone. When a read-back of the ALS Information Register
is done INT is reset to the open drain state.
OVER-VOLTAGE PROTECTION
Over-voltage protection is set at 40V (minimum) for the
LM3530-40 and 23.6V minimum for the LM3530-25. The 40V
version allows typically up to 11 series white LEDs (assuming
3.5V per LED + 400mV headroom voltage for the current sink
= 38.9V). When the OVP threshold is reached the LM3530’s
switching converter stops switching, allowing the output volt-
age to discharge. Switching will resume when the output
voltage falls to typically 1V below the OVP threshold. In the
event of an LED open circuit the output will be limited to
around 40V with a small amount of voltage ripple. The 25V
version allows up to 6 series white LEDs (assuming 3.5V per
25
LED + 400mV headroom voltage for the current sink = 21.4V).
The 25V OVP option allows for the use of lower voltage and
smaller sized (25V) output capacitors. The 40V device would
typically require a 50V output capacitor.
HARDWARE ENABLE
The HWEN input is an active high hardware enable which
must be pulled high to enable the device. Pulling this pin low
disables the I
able input, the PWM input, and resets all registers to their
default state (see
THERMAL SHUTDOWN
In the event the die temperature reaches +140°C, the LM3530
will stop switching until the die temperature cools by 15°C. In
a thermal shutdown event the device is not placed in reset;
therefore, the contents of the registers are left in their current
state.
2
C-compatible interface, the simple enable/dis-
Table
4).
www.national.com