LM3559TLX/NOPB National Semiconductor, LM3559TLX/NOPB Datasheet - Page 17

• Manufacturer Part Number: LM3559TLX/NOPB
• Description: LM3559
• Manufacturer: National Semiconductor
• Series: -r

Specifications of LM3559TLX/NOPB

• Constant Current: Yes
• Constant Voltage: -
• Topology: High Side, PWM, Step-Up (Boost)
• Number Of Outputs: 2
• Internal Driver: Yes
• Type - Primary: Flash/Torch
• Type - Secondary: White LED
• Frequency: 1.8MHz ~ 2.2MHz
• Voltage - Supply: 2.5 V ~ 5.5 V
• Voltage - Output: -
• Mounting Type: Surface Mount
• Package / Case: 16-UFBGA
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

return to the previous Flash current level. During a flash event,
if TX2 is active, the LED current sources will still turn off after
the Flash timeout.
Interrupt.
TX2 Shutdown
TX2 also has the capability to force shutdown. Bit [0] of Con-
figuration Register 2 set to a '1' changes the TX2 mode from
a force Torch when active to a force shutdown when active.
For example, if TX2/INT/GPIO2 is configured for TX2 mode
with active high polarity, and bit [0] of Configuration Register
2 is set to '1' then when TX2 is driven high, the active current
sources (LED1 and/or LED2) will be forced into shutdown.
Once the active current sources are forced into shutdown by
activating TX2, the current sources can only be re-enabled if
TX2 is deactivated and the Flags Register is read back.
GPIO2 MODE
With Bit [3] of the GPIO Register set to 1, the TX2/INT/GPIO2
pin is configured as a logic I/O. In this mode the TX2/INT/
GPIO2 pin is readable and writeable as a logic input/output
via bits [5:4] of the GPIO Register. See
INDICATOR LED/THERMISTOR (LEDI/NTC)
The LEDI/NTC pin serves a dual function, either as a pro-
grammable LED message indicator driver, or as a comparator
input for negative temperature coefficient (NTC) thermistors.
MESSAGE INDICATOR CURRENT SOURCE (LEDI/NTC)
LEDI/NTC is configured as a message indicator current
source by setting Configuration Register 1 bit [4] = 0. The in-
dicator current source is enabled/disabled via Enable Regis-
ter bit [6]. Enable Register bit [7] programs the Message
Indictor for blinking mode. When the message indicator is set
for blinking mode the pattern programmed into the Indicator
Register and Indicator Blinking Register is sent to the Mes-
sage Indicator current source.
Figure 4
details the functionality of the TX2
FIGURE 6. TX2 As an Interrupt Output (During an NTC Event)
Table
9.
17
INTERRUPT OUTPUT (INT MODE)
The TX2/INT/GPIO2 pin can be reconfigured as an active low
interrupt output by setting bit [6] in the GPIO Register to ‘1’
and configuring TX2/INT/GPIO2 as a GPIO2 output. In this
mode, TX2/INT/GPIO2 will pull low when any of these condi-
tions exist.
1.
2.
3.
Once INT is pulled low due to any of the above conditions
having been met, INT will only go back high again if any of the
conditions are no longer true and the Flags Register is read.
The Indicator Blinking Register controls the following (see
Table
1.
2.
The Indicator Register controls the following (see
1.
The LM3559 is configured for NTC mode (Configuration
Register 1 bit [4] = 1) and the voltage at LEDI/NTC has
fallen below VTRIP (1V typical).
The LM3559 is configured for VIN Monitor mode (VIN
Monitor Register bit [0] = 1) and VIN is below the
programmed VIN Monitor Threshold.
The LM3559 is configured for VIN Flash Monitor mode
(VIN Monitor Register bit [3] = 1) and VIN falls below the
programmed VIN Flash Monitor Threshold.
details the functionality of the TX2/INT/GPIO2 input.
Number of blank periods (BLANK #). This has 16
settings. t
t
Pulse width (t
ms in steps of 32 ms. The pulse width is the duration
which the indicator current is at its programmed set point
at the end of the ramp-up time.
Indicator current level (I
indicator current levels from 2.25 mA to 18 mA in steps
of 2.25 mA.
PERIOD
17):
× PERIOD#
BLANK
PULSE
= t
ACTIVE
) has 16 settings between 0 and 480
IND
× BLANK# , where t
). There are 8 message
30102808
Figure 6
www.national.com
ACTIVE
Table
=
16):