MAX16839ASA+ Maxim Integrated Products, MAX16839ASA+ Datasheet - Page 9

• Manufacturer Part Number: MAX16839ASA+
• Description: IC LED DRIVER 100MA 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: HBLED Driverr

Specifications of MAX16839ASA+

• Constant Current: Yes
• Topology: Linear, Open Drain, PWM
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Automotive
• Type - Secondary: High Brightness LED (HBLED)
• Voltage - Supply: 5 V ~ 40 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width) Exposed Pad, 8-eSOIC. 8-HSOIC
• Operating Temperature: -40°C ~ 125°C
• Current - Output / Channel: 100mA
• Internal Switch(s): No
• Operating Supply Voltage: 5 V to 40 V
• Maximum Supply Current: 15 mA to 100 mA
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Frequency: -
• Efficiency: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

If a fault condition is detected, a 2.8mA current source
charges C
flashing during the subsequent power-up cycles. The
choice of the C
Use the following equation to calculate the FLTS capaci-
tor (C
where I
FLTS, t
is the typical voltage (minimum of 15V or the supply
voltage) to which C
V
ory as logic-high, and N is the number of devices in a
multistring application.
The MAX16839 uses a sense resistor to program the
output current sink. To program the LED current, connect
a sense resistor from the current-sense input (CS) to
GND with short traces. The value of the sense resistor
for a given desired current is calculated with the follow-
ing equation:
where V
Characteristics table).
For proper operation, the minimum input voltage must
always be:
where V
sense resistor R
of all series connected LEDs, and DV
U Fault hold time
U Board leakage and FLTS leakage
U Input supply voltage as this affects the maximum
U The number of ICs connected together in case of a
FLTH
FLTS voltage
multistring application
FLTS
is the minimum threshold to detect the fault mem-
FLTS
FLTS
CS(MAX)
V
IN(MIN)
CS
):
FLTS
is the desired fault retention period, V
is the maximum leakage current through
is 203mV (typ) (see the Electrical
High-Voltage, Linear High-Brightness LED
FLTS
C
to memorize the fault condition and avoid
CS
Applications Information
is the maximum voltage drop across the
FLTS
=
_______________________________________________________________________________________
, V
R
V
FLTS
is based on the following conditions:
CS(MAX)
CS
FT(MAX)
=
Programming the LED Current
( )
I
(V
Ω =
FLTS
is charged during a fault event,
FLTS
I
V
+
LED
×
is the total forward voltage
CS
V
t
−
FLTS
FT(MAX)
Driver with Open-LED Fault Detect
V
(V)
(A)
FLTH
×
DO
N
FLTS Capacitor
)
is the maximum
+ ∆
Input Voltage
V
DO
FLTS
dropout voltage of the regulator. If the device is oper-
ated below V
full regulation specification (see the Typical Operating
Characteristics).
For applications that require more than 3 LEDs per string
and have slow supply rise time (> 14Fs), FLTS should, in
general, be connected to ground to avoid false trigger-
ing of the open-LED protection.
The MAX16839 includes a PWM dimming input (DIM)
to control the LED brightness. An application of up to a
10kHz signal is recommended at DIM for proper opera-
tion. DIM also functions as an active-high enable input.
Driving DIM low turns off the output. Driving DIM high or
leaving DIM unconnected turns on the output.
For V
activates a 30FA (typ) pullup current at DIM. When V
undervoltage-lockout threshold, the MAX16839 activates
a 1mA pulldown current.
The MAX16839 can do efficient supply chopped dim-
ming, as it is specially designed for very low startup
delay. The LED current is turned on in 4Fs (typ) after the
supply comes up. The LED current pulse-width modu-
lates in phase with the supply voltage. Minimize the input
filter capacitor after the chopper circuit for fast rise and
fall times of the input supply.
The power dissipation (P
mined from the following equation:
where:
V
I
CV
I
V
DUTY = PWM duty cycle
The MAX16839 thermal specifications are given accord-
ing to the JEDEC-51 guidelines. Good mechanical/ther-
mal design practices must be applied to help maintain
the device junction temperature below the absolute
maximum ratings at all times.
P
IN
LED
IN
CS
D
LED
= supply current
=
= supply voltage
= 203mV drop across R
IN
= LED current
(
V
= total forward voltage for the LED string
IN
> undervoltage-lockout threshold, the MAX16839
×
I
IN
IN(MIN)
) (
+


V
, the output current may not meet the
IN
−
∑
D
V
Supply Chopped Dimming
LED
) of the MAX16839 is deter-
CS
−
V
CS
Power Dissipation
) (
×
PWM Dimming
I
LED
×
DUTY
IN
)


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