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LX1990ILM

P1-P3P4-P6P7-P9P10-P11
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
Copyright 2001
Rev. 1.0c, 2002-05-29
WWW.Microsemi .COM
LX1990
Dual Programmable LED Current Sink
INTEGRATED PRODUCTS
DESCRIPTION
DESCRIPTIONDESCRIPTION
DESCRIPTION
The LX1990 is a dual output current
sink optimized for driving light emitting
diodes. This low cost bipolar IC enables
precise current regulation in LED
display lighting applications, yet
requires far fewer parts than discrete
solutions. The LX1990 is supplied in a
micro-miniature 6 lead MLP package
featuring a 3 x 3 mm footprint, a profile
of less than 1mm, and much improved
thermal performance. Its two output sink
currents are accurately matched and
require only one resistor to program.
Program current is only 1% of the
output currents, and quiescent current is
low, providing a very high efficiency
driver for battery-powered displays.
The LX1990 is based on a current-
mirror architecture that transfers a
reference current produced at the I
SET
pin to each of two open-collector current
sinking outputs. The output stages
multiply this reference current by 100 to
sink independently regulated currents up
to 30 mA.
Light output from LED’s is proportional
to average current through them; they can
easily produce a brightness range of 500:1.
However, color of emitted light is shifte
d
b
y current amplitude. Color shift at lo
w
light levels can be reduced by driving the
LED’s with a constant peak current while
dimming with duty cycle control.
This is achieved by driving the I
SET
resistor with a PWM signal. A 500:1
b
rightness range can be achieved b
y
choosing 270 Hz as the PWM frequency (to
avoid optical beating with 50/60 Hz roo
m
lights) and pulse width from 3.7
milliseconds to 7.4 microseconds.
The LX1990 features a shutdown mode
via the Enable pin. In this mode the
LX1990 consumes less than 1µA and holds
the two open collector output stages off.
This pin may also be used to pulse widt
h
modulate output current. See applications
section for dimming details.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
KEY FEATURES
KEY FEATURESKEY FEATURES
KEY FEATURES
• Programmable Sink Current
0.1 to 30mA x 2 Channels
• Replaces Discrete Transistor
Circuitry With A Single Package
• 300mV Maximum Current Sink
Dropout Voltage at 20mA
• 2.7 to 5.5V Power Supply Input
• I
OUT
Compliance Voltage from
0.1 to 10V
DC
• Enable Input With <1µA Sleep
Current
• Amplitude and PWM Dimming
• Current rise and fall time may
be controlled to reduce EMI
APPLICATIONS
APPLICATIONSAPPLICATIONS
APPLICATIONS
• Cell Phone Display Illumination
• PDA White LED Display
Lighting
• Automotive Display Illumination
• Digital Still Camera
• Camcorders
• Consumer Electronics Front
Panels
PRODUCT HIGHLIGHT
PRODUCT HIGHLIGHTPRODUCT HIGHLIGHT
PRODUCT HIGHLIGHT
5V
LX1990
VDD
I
OUTB
GND
I
OUTA
ISET
R
SET
ENA
V
LOAD
ON/OFF
PACKAGE ORDER INFO
T
A
(°
°°
°C)
LM
Plastic MLP
6-Pin
-40 to 85 LX1990ILM
Note: Available in Tape & Reel.
Append the letter “T” to the part number. (i.e. LX1990ILM-T)
L
L
X
X
1
1
9
9
9
9
0
0
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
Copyright 2001
Rev. 1.0c, 2002-05-29
WWW.Microsemi .COM
LX1990
Dual Programmable LED Current Sink
INTEGRATED PRODUCTS
ABSOLUTE MAXIMUM RAT
ABSOLUTE MAXIMUM RATABSOLUTE MAXIMUM RAT
ABSOLUTE MAXIMUM RATINGS
INGSINGS
INGS
Supply Voltage (V
DD
)........................................................................................6V
ENA Voltage.....................................................................................................6V
I
SET
Maximum Current ..............................................................Internally Limited
I
SET
Maximum Voltage...................................................................................V
DD
I
OUT
Maximum Compliance Voltage...............................................................12V
Current Source Outputs..............................................................................100mA
Operating Temperature Range.........................................................-40°C to 85°C
Maximum Junction Temperature..................................................................125°C
Storage Temperature .....................................................................-65°C to 150°C
Lead Temperature (Soldering, 10sec)........................................................... 300
°C
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to
Ground. Currents are positive into, negative out of specified terminal
.
THERMAL DATA
THERMAL DATATHERMAL DATA
THERMAL DATA
LM
Plastic MLP 6-Pin
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ
θθ
θ
JA
41°
°°
°C/W
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x θ
JA
).
The θ
JA
numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
PACKAGE PIN OUT
PACKAGE PIN OUTPACKAGE PIN OUT
PACKAGE PIN OUT
VDD
ENA
GND
I
OUTB
I
OUTA
ISET
1
2
3
4
5
6
LM PACKAGE
(Top View)
1990
xxxx
LMI
LM PACKAGE MARKINGS
xxxx – Denotes Date Code / Lot Identification
FUNCTIONAL PIN DESCR
FUNCTIONAL PIN DESCRFUNCTIONAL PIN DESCR
FUNCTIONAL PIN DESCRIPTION
IPTIONIPTION
IPTION
NAME DESCRIPTION
V
DD
Input Supply
GND Common ground reference
ENA
Chip Enable Input. If logic high, current source outputs are enabled. If logic low, internal power is disconnected
from the VDD pin, disabling all functions. Logic threshold is 1.2 V.
I
OUTA
&
I
OUTB
Output Current Source. Two separate constant current outputs. Outputs may be loaded in any combination
without affecting regulation of the loaded output. If only one output is needed I
OUTA
& I
OUTB
must be shorted
together. In this case the value of ISET resistor must be doubled. Compliance voltage range is 0.1V to 10V.
I
SET
Output current programming pin.
P
P
A
A
C
C
K
K
A
A
G
G
E
E
D
D
A
A
T
T
A
A
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page
3
Copyright 2001
Rev. 1.0c, 2002-05-29
WWW.Microsemi .COM
LX1990
Dual Programmable LED Current Sink
INTEGRATED PRODUCTS
RECOMMENDED OPERATIN
RECOMMENDED OPERATINRECOMMENDED OPERATIN
RECOMMENDED OPERATING CONDITIONS
G CONDITIONSG CONDITIONS
G CONDITIONS
LX1990
Parameter
Min Typ Max
Units
Supply Voltage (V
DD
) 2.7 5.5 V
ENA (ENABLE) Input Voltage 0 V
DD
V
I
SET
Voltage 0 1.25 V
I
SET
Current 0 300 µA
I
OUTA
/ I
OUTB
Compliance Voltage Range 0.1 10 V
I
OUTA
/ I
OUTB
Output Current Range 0.1 30 mA
ELECTRICAL CHARACTER
ELECTRICAL CHARACTERELECTRICAL CHARACTER
ELECTRICAL CHARACTERISTICS
ISTICSISTICS
ISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C ≤ T
A
≤ 85°C and the
following test conditions: V
DD
= 2.7 to 5.5 V
DC
, I
SET
= 200µA, V
OUT
≤ 5.5V, VLOAD ≤ 10V. Typical values are at T
A
= 25°C
LX1990
Parameter Symbol Test Conditions
Min Typ Max
Units
Power Characteristics
Quiescent Current I
_QUI
VDD = 2.7V; ISET = 0uA 1.4 2 mA
Quiescent Current I
_QUI
VDD = 5.5V; ISET = 300uA 3.0 4 mA
Sleep Current
1
I
_SLEEP
VDD = 5.5V, ENA ≤ 0.4V
0.08 1 µA
Enable Input
Enable Logic Threshold V
TH_EN
0.8 1.55 2.4 V
Enable Input Current I
IN_EN
ENA = V
DD
= 5.5V 4 10 µA
I
SET
to Out Pulse Response T
D(ON)
1.2 2 µS
I
SET
to Out Pulse Response T
D(OFF)
1.4 2 µS
ISET Input
I
SET
Current Range I
ISET
R
SET
terminated to GND 0 300 µA
I
SET
Voltage V
ISET
I
SET
= 200uA 1.225 1.25 1.275 V
DC
Output Characteristics
Output Current Amplitude I
OUT
0.5 < V
OUT
< 5.5V, I
SET
= 200µA 18.5 20 21.5 mA
DC
OUTA to OUTB Current Matching I
OUT_MATCH
I
OUT
= 20mA ; (I
OUTA
– I
OUTB
) / I
OUTA
* 100 0.4 5 %
ISET to IOUT Current Ratio I
OUT_RATIO
I
OUT
/I
SET
; I
SET
= 200µA ; V
DD
= 5.5V 102
ISET to IOUT Current Ratio I
OUT_RATIO
I
OUT
/I
SET
; I
SET
= 200µA ; V
DD
= 2.7V 99
Output Current I
SET
= 0µA I
OUT_ZERO
0.5 < V
OUT
< V
LOAD
, I
SET
= 0µA 10 100 µA
DC
Dropout Voltage
2
V
DROPOUT
I
OUT
= 20mA 150 300 mV
Dropout Voltage
2
V
DROPOUT
I
OUT
= 30mA 200 400 mV
Maximum Output Current, I
SET
Shorted To Gnd. Each Output
I
SC
V
ISET
= Zero Volts; VDD=5V 100 mA
DC
Output Off State Current I
OUTOFF
ENA
≤ 0.4V
20 µA
DC
1
At enable voltages greater than 0.4V but less than 0.8V the outputs will remain off but the sleep current may be greater than 1µA.
2
Dropout is defined as the OUTA/B to GND voltage at which the output current sink drops 10% from the nominal value.
E
E
L
L
E
E
C
C
T
T
R
R
I
I
C
C
A
A
L
L
S
S
P1-P3P4-P6P7-P9P10-P11

LX1990ILM

Mfr. #:
Buy LX1990ILM
Manufacturer:
Microchip / Microsemi
Description:
IC LED DRIVER LIN DIM 30MA 6MLP
Lifecycle:
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