|
|
PDF LP3942 Data sheet ( Hoja de datos )
| Número de pieza | LP3942 | |
| Descripción | The Dual RGB LED Controller | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LP3942 (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
|
No Preview Available !
PRELIMINARY
wwNwov.DeamtbaeSrh2e0e0t44U.com
LP3942
The Dual RGB LED Controller with 1.5x/2x Charge Pump
and SPI Interface
General Description
The LP3942 is an integrated stand-alone RGB LED control-
ler with a high efficiency and low noise programmable 1.5x
and 2x charge pump. The RGB LEDs are controlled through
the low voltage SPI interface. RGB programmability allows
unique color and brightness control with both RGB outputs.
The color control has preselected color settings for color
blending. The LED current control is done using constant
current sinks that can be also used as switches. The non-
overlapping RGB output PWM control minimizes the input
noise.
See also: LP3931, LP3933 and LP3936 Lighting Manage-
ment Units
Features
n Pre-regulated 1.5x and 2x charge pump with regulated
output (4.5V and 5.0V)
n 2 separately controlled PWM RGB LED drivers with
programmable color and brightness
n Overlapping and non-overlapping RGB mode
n Wide input voltage range 3V–5.0V
n Output current up to 120 mA
n Low voltage SPI interface
n Programmable low current Standby mode
n Tiny LLP24 package (5mm*4mm*0.8mm)
Applications
n Cellular Phones, PDAs
Typical Application
© 2004 National Semiconductor Corporation DS201292
20129201
www.national.com
1 page  
Logic Interface Characteristics (1.8V Logic)
Symbol
Parameter
LOGIC INPUTS
VIL Input Low Level
VIH Input High Level
IH Logic Input Current
fSPI
tNRST
Interface Clock
Reset Pulse Width
Conditions
SS, SI, SCK, NRST
SS, SI, SCK, NRST
SS, SI, SCK
NRST (1 MΩ pull-down)
NRST
www.DataSheet4U.com
Limit
Units
Min Typ Max
0.5 V
1.2 V
−1 1 µA
−1 3 µA
10 MHz
50 µs
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of
the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the
Electrical Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pins.
Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 160˚C (typ.) and disengages at TJ =
140˚C (typ.).
Note 4: For detailed soldering specifications and information, please refer to National Semiconductor Application Note 1187: Leadless Leadframe
Package (LLP).
Note 5: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged
directly into each pin. MIL-STD-883 3015.7
Note 6: In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be
derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 105˚C), the maximum power
dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the
following equation: TA-MAX = TJ-MAX-OP − (θJA x PD-MAX).
Note 7: Junction-to-ambient thermal resistance (θJA) is taken from a thermal modeling result, performed under the conditions and guidelines set forth in the JEDEC
standard JESD51-7. The test board is a 4-layer FR-4 board measuring 102 mm x 76 mm x 1.6 mm with a 2x1 array of thermal vias. The ground plane on the board
is 50 mm x 50 mm. Thickness of copper layers are 36 µm/18 µm/18 µm/36 µm (1.5 oz/1 oz/1 oz/1.5 oz). Ambient temperature in simulation is 22˚C, still air. Power
dissipation is 1W.
The value of θJA of the LP3942 in LLP-24 could vary widely, depending on PWB material, layout, and environmental conditions. In applications where high maximum
power dissipation exists (high VIN, high IOUT), special care must be paid to thermal dissipation issues. For more information on these topics, please refer to
Application Note 1187: Leadless Leadframe Package (LLP) and the Power Efficiency and Power Dissipation section of this datasheet.
Note 8: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm.
Note 9: CIN, COUT, C1, and C2 : Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics. Minimum capacitance value for
CIN, C1, and C2 capacitors is 70% of nominal value. This tolerance includes manufacturing tolerance, temperature coefficient and voltage dependency (roll-off). COUT
minimum effective capacitance value is 3.0 µF.
Note 10: Output voltage accuracy does not include VDD (2.78V supply voltage) tolerance.
Note 11: The quiescent current does not include the current setting resistors’ current.
5 www.national.com
5 Page 
RGB Functionality (Continued)
www.DataSheet4U.com
RGB Framing with 50% Intensity
20129209
The brightness control is logarithmic and is programmed as
follows.
Bright
[2:0]
000
001
010
011
100
101
110
111
Color
Brightness
[%]
0
1.56
3.12
6.25
12.5
25.0
50.0
100
Ratio to
Max Brightness
0
1/64
1/32
1/16
1/8
1/4
1/2
1/1
Color[3:0]
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Red
active/cycle [%]
100
0
0
50
0
50
33
50
25
25
75
75
0
25
0
25
Green
active/cycle [%]
0
100
0
50
50
0
33
25
50
25
25
0
75
75
25
0
Non-Overlapping Mode
The non-overlapping mode has 16-programmed colors (dif-
ferent R, G and B ratio → different color). Since the R, G and
B are split in to non-overlapping slots the output current
through the RGB LED can be calculated by following equa-
tion:
IAVG = (CR* IR + CG* IG + CB* IB)*B,
C = Color [%] (see table below)
B = Brightness [%] (see table below)
The 16 colors can be selected as follows. Please note that
exact color depends on LED current and type.
Blue
active/cycle [%]
0
0
100
0
50
50
33
25
25
50
0
25
25
0
75
75
RGB Color
(depends on RGB LED type)
red
green
blue
yellow
green/blue
maroon
white
dark pink
dark green
lt blue
lt orange
orange
lt green
med green
blue/green
purple
11 www.national.com
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet LP3942.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LP3941 | LP3941A Cellular Phone Power Management Unit (Rev. D) |  Texas Instruments |
| LP3941A | Cellular Phone Power Management Unit | National Semiconductor |
| LP3942 | The Dual RGB LED Controller | National Semiconductor |
| LP3943 | RGB/White/Blue 16-LED Fun Light Driver | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |