LX1991
TM
廬
Six Output Programmable LED Current Sink
P
RODUCTION
D
ATA
S
HEET
DESCRIPTION
KEY FEATURES
WWW .
Microsemi
.C
OM
LED Display Driver:
This six channel
current sink driver is ideal for controlling
brightness and hue of high quality
dimmable LED displays. High accuracy,
dual mode dimming, and controlled current
switching time provides consistent color
hue, at brightness ratios of up to 1000:1,
and keeps electro magnetic emissions in
check.
Its wide compliance voltage range
combined with 43 volt breakdown cap-
ability make the LX1991 ideal for
automotive in-dash displays.
Precision current control:
Precision
current mirror circuitry sets all channels to
the same current with a single programming
input. Sinking current value can be pro-
grammed up to 30 mA per channel with a
single resistor or potentiometer from I
SET
+
to
I
SET
-
. Channel to channel matching is ty-
pically within 鹵1 percent of channel mean
at the rated output current.
Dual Mode Dimming:
Display dimming
can be achieved by controlling either
current amplitude or duty cycle, and both
methods can be employed at the same time.
1000:1 Dimming Range:
The DIG_DIM
input accepts a TTL or CMOS logic signal
that controls duty cycle of the output
currents.
Independent Channels:
The six channels
feature independent regulation with respect
to output voltage, so one does not affect the
others. Any one or more outputs can be left
unloaded
without
affecting
current
regulation of the other channels. Multiple
channels can also be connected together to
sink more current in a single load.
EMI Control:
Rise and fall time of sink
currents are precisely controlled by placing
a capacitor on the SLOPE_C pin. Special
control circuitry maintains symmetrical rise
and fall times, preserving the LX1991鈥檚
ability to provide accurate output current
response to very narrow input pulses on the
DIG_DIM pin.
Power Handling:
The LX1991 is
supplied in a 4x4 MLPQ package capable
of 1.5 watts dissipation. Logic Enable: A
separate input puts the LX1991 to sleep at
less than 1 uA I
DD
.
Six precision independent
current sink channels
Simultaneous Analog and
Digital Dimming Modes
Precision programming of
current rise & fall times
1% band gap reference
40 volt rated output stages
3V / 5V logic input compatible
1.5 watt power dissipation
On-chip thermal shutdown
16 Pin 4 x 4 MLPQ Package
BENEFITS
Consistent LED color hue
results from high current
accuracy
1000:1 dimming ratio with
digital dimming
Lowered emissions with
current slope programming
Reduced component count
for compact designs
Drive up to 108 colored
LED鈥檚 per IC (6 x 18 @ 2.1
volts)
Drive up to 60 white or blue
LED鈥檚 per IC (6 x 10 @ 3.8
volts)
IMPORTANT:
For the most current data, consult
MICROSEMI鈥檚
website:
http://www.microsemi.com
PRODUCT HIGHLIGHT
+36V
5V
LX1991
54 White LED鈥檚
V
F
~3.7V
@20mA
SINK1
Bill of Materials
1
1
1
54
57
LX1991
Cap
Resistor
White LEDs
Total Count
SLEW CONTROL
PWM
SIGNAL
ON
VDD
CSLOPE
SINK2
DIG_DIM
SINK3
SINK4
SINK5
ISET+
SINK6
GND
LX1991
ENA
OFF
1.5K
ISET-
LX1991
LX1991
PACKAGE ORDER INFO
T
J
(擄C)
-40 to 85
Copyright
漏
2001
Rev. 1.0, 5/18/2005
M
IN
V
DD
4.5
M
AX
V
DD
5.5V
LQ
Plastic 4x4 MLPQ
16-PIN
LX1991ILQ
Page 1
RoHS Compliant / Pb-free Transition DC: 0436
Note: Available in Tape & Reel. Append the letters 鈥淭R鈥?to the part number. (i.e. LX1991ILQ-TR)
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
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