LM4970
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SNVS312D – JANUARY 2005 – REVISED MAY 2013
LM4970
Audio Synchronized Color LED Driver
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FEATURES
DESCRIPTION
•
•
The LM4970 is a LED driver with an audio
synchronization mode that virtually eliminates the
need for real time software processing for LED
lighting effects. The LM4970 includes three individual
PWM color LED drivers that provide up to 42mA of
current drive for each PWM LED output.
1
2
•
•
•
•
Audio Synchronized Color LED Driver
User Defined LED Pattern, Color, and Intensity
Capability
Programmable:
–
LED Drive Current
–
PWM Frequency
–
High Pass Filter Frequency Select
–
Audio Input Signal Gain
Eliminates External LED Current Limiting
Resistors
I2C Compatible Interface
Ultra Low Shutdown Current
APPLICATIONS
•
•
•
Cell Phones
Portable MP3, CD, DVD, AAC players
PDA's
The LM4970 features an audio synchronization mode
where the audio input signal that is mixed in from
three audio inputs is filtered into three frequency
bands, with each frequency band assigned to a
specific PWM LED driver.
The PWM LED drivers can also be directly
programmed through an I2C compatible interface for
applications where user defined LED pattern, color,
and intensity programmability is a priority.
The LM4970 also features an audio input gain control
which allows the user to increase the gain if the audio
input signal does not create a bright enough effect on
the LEDs. The LM4970 is a feature rich LED driver
that is available in a space saving 14 pin nonpullback WSON package.
KEY SPECIFICATIONS
•
•
LED Drive Current per Channel (VDD = 5V):
42mA (2X Setting)
Shutdown Current, VDD = 5V: 1.5μA (Typ)
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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LM4970
SNVS312D – JANUARY 2005 – REVISED MAY 2013
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Block Diagram
VDD
2
I CVDD
2
I CVDD
2
I C
BUS
VI H
SCL
SDA
CONTROL
INTERFACE
PWM
RANDOMIZER
ADR
VDD or VDDBOOST
VI L
LED1
AUDIO
SYNC
FILTER
MIN
LED
CURRENT
CONTROL
LED2
LED3
LIN
RIN
FILT
GND
LGND
Figure 1. Block Diagram
Connection Diagram
FILT
1
14
LED1
VDD
2
13
LED2
MIN
3
12
LGND
GND
4
11
LED3
LIN
5
10
ADR
RIN
6
9
SCL
I CVDD
7
8
SDA
2
Figure 2. 14 pin NHK Package (Top View)
See Package Number NHK0014A
2
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PIN DESCRIPTIONS
Pin
Name
Pin Description
1
FILT
Low Pass Filter Input
2
VDD
Power Supply Pin
3
MIN
Mono Audio Input
4
GND
Ground
5
LIN
Left Audio Input
6
RIN
Right Audio Input
7
I2CVDD
I2C Interface Power Supply
8
SDA
I2C Data
9
SCL
I2C Clock
10
ADR
I2C Address Select
11
LED3
LED output 3
12
LGND
LED ground
13
LED2
LED output 2
14
LED1
LED output 1
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings (1) (2) (3)
Supply Voltage
6.0V
−65°C to +150°C
Storage Temperature
−0.3V to VDD +0.3V
Input Voltage
Power Dissipation (4)
Internally Limited
ESD Susceptibility (5)
2000V
(6)
200V
ESD Susceptibility
ESD Susceptibility (7)
100V
Junction Temperature
150°C
Thermal Resistance
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
θJA (NHK0014A) (8)
57°C/W
θJC (NHK0014A)
12°C/W
All voltages are measured with respect to the GND pin unless otherwise specified.
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which specify specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and the ambient temperature,
TA. The maximum allowable power dissipation is PDMAX = (TJMAX - TA) / θJA or the number given in Absolute Maximum Ratings,
whichever is lower.
Human body model, 100pF discharged through a 1.5kΩ resistor.
Machine Model, 200pF–220pF discharged through all pins, except pins 13 and 14.
Machine Model, 200pF–220pF discharge through pins 13 and 14 (LED1 and LED2).
The given θJA is for an LM4970SD mounted on a PCB with a 2in2 area of 1oz printed circuit board copper ground plane.
Operating Ratings
Temperature Range (TMIN ≤ TA ≤ TMAX)
−40°C ≤ TA ≤ +85°C
2.7V ≤ VDD ≤ 5.5V (1)
Supply Voltage
(1)
2.5V ≤ I2CVDD ≤ 5.5V
VDD may be used to power the LEDs. It may be necessary to drive the LEDs from a boost (VDDBOOST) found within the system.
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Control Interface Electrical Characteristics (1) (2)
The following specifications apply for 3V ≤ VDD ≤ 5V unless otherwise specified. Limits apply for TA = 25°C.
Symbol
Parameter
Conditions
LM4970
Typical
(3)
Limits (4) (5)
Units
(Limits)
t1
SCL period
2.5
μs (min)
t2
SDA Setup Time
100
ns (min)
t3
SDA Stable Time
0
ns (min)
t4
Start Condition Time
100
ns (min)
t5
Stop Condition Time
100
ns (min)
VIH
Digital Input High Voltage
0.7 x I2CVDD
V (min)
Digital Input Low Voltage
2
V (max)
VIL
(1)
(2)
(3)
(4)
(5)
0.3 x I CVDD
All voltages are measured with respect to the GND pin unless otherwise specified.
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which specify specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
Typicals are measured at +25°C and represent the parametric norm.
Limits are ensured to AOQL (Average Outgoing Quality Level).
Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
Color LED Driver Electrical Characteristics VDD = 5.0V (1) (2) (3)
The following specifications apply for VDD = 5.0V unless otherwise specified. Limits apply for TA = 25°C.
Symbol
Parameter
IDDRGB
Supply Curent
ISDRGB
Shutdown Current
ILED
LED Drive Current
fPWM
PWM Frequency
Input Signal Level Gain Control
(1)
(2)
(3)
(4)
(5)
(6)
4
Conditions
LM4970
Typical
(4)
Limits (5) (6)
Units
(Limits)
2.5
4
mA (max)
Shutdown Mode
1.5
3.5
μA (max)
.66X current drive setting
14
mA
1X current drive setting
21
mA
1.33X current drive setting
30
mA
2X current drive setting
42
PWM_F = '01'
60
Hz
Maximum setting
12
dB
Minimum setting
–11
dB
23
mA (min)
All voltages are measured with respect to the GND pin unless otherwise specified.
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which specify specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
Shutdown current and supply current are measured in a normal room environment. All digital input pins are connected to I2CVDD.
Typicals are measured at +25°C and represent the parametric norm.
Limits are ensured to AOQL (Average Outgoing Quality Level).
Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
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Color LED Driver Electrical Characteristics VDD = 3.0V (1) (2) (3)
The following specifications apply for VDD = 3.0V unless otherwise specified. Limits apply for TA = 25°C.
Symbol
Parameter
IDDRGB
Supply Curent
ISDRGB
Shutdown Current (3)
ILED
LED Drive Current
fPWM
PWM Frequency
Input Signal Level Gain Control
(1)
(2)
(3)
(4)
(5)
(6)
Conditions
LM4970
Typical
(4)
Limits (5) (6)
Units
(Limits)
2.2
3
mA (max)
Shutdown Mode
0.5
2
μA (max)
.66X current drive setting
12
mA
1X current drive setting
18
mA
1.33X current drive setting
27
2X current drive setting
35
PWM_F = '01'
60
Hz
Maximum setting
12
dB
Minimum setting
–11
dB
mA
21
mA (min)
All voltages are measured with respect to the GND pin unless otherwise specified.
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which specify specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
Shutdown current and supply current are measured in a normal room environment. All digital input pins are connected to I2CVDD.
Typicals are measured at +25°C and represent the parametric norm.
Limits are ensured to AOQL (Average Outgoing Quality Level).
Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
External Components Description
Components
Functional Description
1.
Ci
This is the input coupling capacitor. It blocks the DC voltage and couples the input signal to the amplifier's input
terminals. CIN also creates a highpass filter with an internal 20kΩ resistor at fc = 1/(2π.20000.Ci).
2.
CS
This is the supply bypass capacitor. It filters the supply voltage applied to the VDD pin and helps reduce the noise at
the VDD pin.
3.
Cfilt
This capacitor creates a low pass filter with an internal 4kΩ resistor at fc = 1/(2π*4000*Cfilt). This pole set at fc
determines the high cutoff frequency for the low band PWM color LED driver output, LED1.
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Typical Performance Characteristics (1)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.047μF, HPF = 3.5kHz setting)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.068μF, HPF = 3.5kHz setting)
24
LED DRIVE CURRENT (mA)
LED DRIVE CURRENT (mA)
24
20
16
12
8
4
0
20
200
2k
20
16
12
8
4
0
20
20k
FREQUENCY (Hz)
20k
Figure 4.
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.1μF, HPF = 3.5kHz setting)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.22μF, HPF = 3.5kHz setting)
24
LED DRIVE CURRENT (mA)
LED DRIVE CURRENT (mA)
20
16
12
8
4
0
20
200
2k
20
16
12
8
4
0
20
20k
200
2k
20k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 5.
Figure 6.
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.47μF, HPF = 3.5kHz setting)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 0.68μF, HPF = 3.5kHz setting)
24
20
LED DRIVE CURRENT (mA)
LED DRIVE CURRENT (mA)
24
16
12
8
4
0
20
6
2k
Figure 3.
24
(1)
200
FREQUENCY (Hz)
200
2k
20k
20
16
12
8
4
0
20
200
2k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 7.
Figure 8.
20k
Audio input level set at 1VRMS. The input summing amplifier gain is set to 12dB.
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Typical Performance Characteristics(1) (continued)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 1μF, HPF = 3.5kHz setting)
Audio Sync LED Frequency Response
(Left - lowband, Mid - midband, Right - highband)
(Cfilt = 2.2μF, HPF = 3.5kHz setting)
24
LED DRIVE CURRENT (mA)
LED DRIVE CURRENT (mA)
24
20
16
12
8
4
0
20
200
2k
20
16
12
8
4
0
20
20k
200
2k
20k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 9.
Figure 10.
Highpass Filter Frequency Response
vs HPF_F setting
(Top - 3.5kHz setting, Mid - 6.3kHz setting, Bot -8.9kHz
setting)
Low Pass Filter Frequency Responsevs Cfilt
(From Left to Right: Cfilt (μF) = 2.2, 1.0, 0.68, 0.47, 0.22,
0.1, 0.068, 0.047, No Cfilt)
24
LED DRIVE CURRENT (mA)
LED DRIVE CURRENT (mA)
24
20
16
12
8
4
0
20
200
2k
20k
20
16
12
8
4
0
20
200
2k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 11.
Figure 12.
20k
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APPLICATION INFORMATION
Figure 13. I2C Timing Diagram
Figure 14. I2C Bus Format
Table 1. Color LED Driver Chip Address (1)
A7
A6
A5
A4
A3
A2
A1
A0
Chip Address
1
1
1
1
0
1
EC
0
ADR = 0
1
1
1
1
0
1
0
0
ADR = 1
1
1
1
1
0
1
1
0
(1)
EC - externally configured by ADR pin
Table 2. Color LED Driver Control Registers
D7
D6
D5
D4
D3
D2
D1
D0
Mode Select
Register Name
0
0
0
MS4
MS3
MS2
MS1
MS0
Frequency Select
0
1
0
FS4
FS3
FS2
FS1
FS0
Pattern Select
0
1
1
PS4
PS3
PS2
PS1
PS0
Current Select
1
0
CS5
CS4
CS3
CS2
CS1
CS0
Gain Select
1
1
GS5
GS4
GS3
GS2
GS1
GS0
Table 3. Mode Select Register
Data Bit
MSO
8
Bit Name
Default Value
I2C_SD
1
MS1
I2C_RST
0
MS2
RAND
1
MS3
RSVD
0
MS4
RSVD
0
Condition
Function
0
Enables device power up mode
1
Enables device shutdown mode
0
Enables device normal operation
1
Enables device RESET, excluding the I2C register settings
0
Disables the audio synchronization randomizer
1
Enables the audio synchronization randomizer
0
1
0
1
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RESERVED
RESERVED
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Table 4. Frequency Select Register
Data Bit
Bit Name
Default
Value
FSO
PWM_FO
0
Condition
Function
0
Programs the oscillation frequency of the PWM. PWM oscillation frequency is
set as follows:
1
PWM_F
PWM Frequency
00
15kHz
01
60Hz
10
7Hz
11
4Hz
0
FS1
PWM_F1
0
1
FS2
RSVD
0
FS3
HPF_FO
0
0
RESERVED
1
0
Programs the internal high pass filter cutoff frequency. High pass filter cutoff
frequency is set as follows:
1
0
FS4
HPF_F1
1
HPF_F
High Pass Filter Cutoff Frequency
00
3.5kHz
01
6.3kHz
10
6.3kHz
11
8.9kHz
1
Table 5. Pattern Select Register
Data Bit
Bit Name
Default Value
PSO
I2C_SEL
0
PS1
I2C_LED1
0
PS2
I2C_LED2
0
PS3
I2C_LED3
0
PS4
RSVD
0
Condition
Function
0
Enables LED drivers to be controlled by audio
synchronization
1
Enables LED drivers to be controlled through I2C
0
Disables the LED1 driver, if I2C_SEL is set
1
Enables the LED1 driver, if I2C_SEL is set
0
Disables the LED2 driver, if I2C_SEL is set
1
Enables the LED2 driver, if I2C_SEL is set
0
Disables the LED3 driver, if I2C_SEL is set
1
Enables the LED3 driver, if I2C_SEL is set
0
RESERVED
1
RESERVED
Table 6. Current Select Register
Data Bit
Bit Name
Default
Value
CSO
ILED1_0
0
Condition
Function
0
Programs the current drive of the LED1 driver. Current drive for LED1 is set
as follows:
1
0
CS1
ILED1_1
1
1
CS2
ILED2_0
0
0
1
0
CS3
ILED2_1
1
1
ILED1
Current Drive Setting
00
0.66X
01
1X
10
1.33X
11
2X
Programs the current drive of the LED2 driver. Current drive for LED2 is set
as follows:
ILED2
Current Drive Setting
00
0.66X
01
1X
10
1.33X
11
2X
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Table 6. Current Select Register (continued)
Data Bit
Bit Name
Default
Value
CS4
ILED3_0
0
Condition
Function
0
Programs the current drive of the LED3 driver. Current drive for LED3 is set
as follows:
1
0
CS5
ILED3_1
1
1
ILED3
Current Drive Setting
00
0.66X
01
1X
10
1.33X
11
2X
Table 7. Gain Select Register
Data Bit
Bit Name
Default
Value
GSO
MGAIN0
0
GS1
MGAIN1
1
Condition
Function
0
Programs the gain response of the midband audio synchronized filter which
drives the LED2 PWM color LED driver for the midband audio frequencies.
Gain is set as follows:
1
0
1
0
GS2
GS3
GS4
MGAIN2
SGAIN0
SGAIN1
0
0
1
1
0
SGAIN2
000
Midband Filter Gain
minimum
001
low
010
medium
011
high
100
maximum
Programs the audio gain of the input summing amplifier. Gain is set as
follows:
1
SGAIN
0
000
–11dB
1
001
–6.5dB
0
GS5
MGAIN
0
1
Input Signal Gain
010
0dB
011
3.5dB
100
6dB
101
10dB
110
12dB
I2C COMPATIBLE INTERFACE
The LM4970 uses a serial bus which conforms to the I2C protocol to control the chip’s functions with two wires:
clock (SCL) and data (SDA). The clock line is uni-directional. The data line is bi-directional (open-collector) with a
pullup resistor (typically 10kΩ). The maximum clock frequency specified by the I2C standard is 400kHz. In this
discussion, the master is the controlling microcontroller and the slave is the LM4970.
The I2C address for the LM4970 is determined using the ADR pin. The LM4970’s two possible I2C chip
addresses are of the form 111101X10 (binary), where X1 = 0, if ADR is logic low; and X1 = 1, if ADR is logic high.
If the I2C interface is used to address a number of chips in a system, the LM4970’s chip address can be changed
to avoid any possible address conflicts.
The bus format for the I2C interface is shown in Figure 14. The data is latched in on the rising edge of the clock.
The bus format diagram is broken up into six major sections:
The “start” signal is generated by lowering the data signal while the clock signal is high. The start signal will alert
all devices attached to the I2C bus to check the incoming address against their own address.
The 8-bit chip address is sent next, most significant bit first. Each address bit must be stable while the clock level
is high.
10
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After the last bit of the address bit is sent, the master checks for the LM4970’s acknowledge. The master
releases the data line high (through a pullup resistor). Then the master sends a clock pulse. If the LM4970 has
received the address correctly, then it holds the data line low during the clock pulse. If the data line is not low,
then the master should send a “stop” signal (discussed later) and abort the transfer.
The 8 bits of data are sent next, most significant bit first. Each data bit should be valid while the clock level is
stable high.
After the data byte is sent, the master must check for another acknowledge to see if the LM4970 received the
data.
If the master has more data bytes to send to the LM4970, then the master can repeat the previous two steps
until all data bytes have been sent.
The “stop” signal ends the transfer. To signal “stop”, the data signal goes high while the clock signal is high. The
data line should be held high when not in use.
AUDIO SYNCHRONIZATION MODE
The LM4970 features an audio synchronization mode where each PWM color LED driver output is dependent on
the audio input signal. The audio synchronization mode allows each LED output to react to the amplitude of the
audio input signal, according to the LED output's assigned frequency band. Audio synchronization mode is
activated by clearing the I2C_SEL bit in the Pattern Select Register.
The audio synchronization filter separates the mixed audio signal into three frequency bands: lowband, midband,
and highband. Each frequency band is assigned to a particular PWM LED output, with lowband controlling the
duty cycle of the LED1 output, midband controlling the duty cycle of the LED2 output, and highband controlling
the duty cycle of the LED3 output. This occurs whenever the audio synchronization randomizer is not turned on.
The operation of the audio synchronization randomizer is explained in the AUDIO SYNCHRONIZATION
RANDOMIZER section. The duty cycle of any given LED output is dependent upon the amplitude of the audio
signal for its particular frequency band. An increase in the amplitude of the audio signal will increase the duty
cycle of the PWM LED driver. LEDs driven with a higher duty cycle results in a brighter lighting effect.
The LM4970 has three single-ended analog audio inputs designated MIN, LIN, and RIN, where mono voice data is
routed to MIN and stereo MP3 or stereo FM radio data is routed to LIN and RIN. Audio signals coupled in from MIN,
LIN, and RIN are mixed together by an audio input summing amplifier. The gain of the audio input summing
amplifier is programmed by the SGAIN bits of the Gain Select Register. Increasing the gain of the audio
input summing amplifier will increase the intensity of the LEDs in audio synchronization mode.
The pole of the low pass filter band is set by the filter cap, Cfilt, and an internal 4kΩ resistor. The pole of the high
pass filter band is internally set by programming the HPF_F bits of the Frequency Select Register. The
midband frequency band is a function of the lowband and highband poles. The gain response of the midband
frequency band can be set by programming the MGAIN bits of the Gain Select Register.
To minimize LED leakage between audio bands, care should be taken when selecting input gain, midband gain,
Cfilt, and LED current drive. There is a trade off between LED brightness and LED leakage in other audio bands.
Leakage can be minimized by reducing LED current drive and input gain. Please refer to the frequency response
graphs found in the Typical Performance Characteristics section as a guideline to minimize LED leakage.
AUDIO SYNCHRONIZATION RANDOMIZER
The LM4970 features a randomizer block that randomizes the frequency band assigned to each PWM LED driver
during audio synchronization operation. The randomizer is activated by setting the RAND bit in the Mode Select
Register. Clearing the RAND bit will disable the randomizer. The randomizer can only be activated when the
LM4970 is programmed to audio synchronization mode. The interval at which randomizer assigns a new
frequency band is set to occur once every 3.2 seconds. The randomizer ensures that all the colored LEDs will
light up over a long duration even if the audio input has a fixed frequency.
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I2C PATTERN MODE
The LM4970 features an I2C pattern mode for applications where direct control of the LED outputs is required.
I2C pattern mode is activated by setting the I2C_SEL bit in the Pattern Select Register. The LED1 output duty
cycle can be programmed to 100% by setting the I2C_LED1 bit in the Pattern Select Register. Clearing the
I2C_LED1 bit sets the LED1 output duty cycle to 0%. The LED2 output duty cycle can be programmed to 100%
by setting the I2C_LED2 bit in the Pattern Select Register. Clearing the I2C_LED2 bit sets the LED2 output duty
cycle to 0%. The LED3 output duty cycle can be programmed to 100% by setting the I2C_LED3 bit in the Pattern
Select Register. Clearing the I2C_LED3 bit sets the LED3 output duty cycle to 0%. Color LEDs driven at 100%
duty cycle are fully on, and driven at 0% duty cycle are fully off.
PWM FREQUENCY
The PWM frequency of the color LED drivers is programmed through the PWM_F bits of the Frequency
Select Register. The LM4970 features four different PWM frequency settings: 15kHz, 60Hz, 7Hz, and 4Hz. PWM
frequency is analogous to the sampling rate of the audio input signal. A higher PWM frequency setting will result
in a more accurate LED representation of the audio input signal in the audio synchronization mode. However, a
PWM frequency that is set too high will decrease the ON time of the LED which will result in reduced LED
intensity. A PWM frequency setting of 60Hz results in an optimal balance between LED accuracy and intensity.
DRIVING RGB LED MODULES
The LM4970’s PWM LED outputs can be used to drive individual color LEDs or RGB LED modules. When
driving RGB LED modules in audio synchronization mode, the color and intensity of the RGB LED module will be
dependent on the audio input signal. In I2C pattern mode, the RGB LED module can be set to any of seven
distinct colors, based on the status of the I2C_LED1, I2C_LED2, and I2C_LED3 bit settings.
VDD
Cs
2
I CVDD
VDD
VDD
0.1 PF
2
RGB LED
I CVDD
J1
SCL
SDA
CONTROL
INTERFACE
PWM
RANDOMIZER
ADR
extVDD
2
I C Interface
6 Pin Header
RED
LED1
LED1
Ci1
AUDIO
SYNC
FILTER
MIN
0.22 PF
LED
CURRENT
CONTROL
GREEN
LED2
LED2
BLUE
Ci2
LIN
LED3
0.22 PF
Ci3
LED3
RIN
0.22 PF
FILT
GND
LGND
Cfilt
1 PF
Figure 15. Reference Design Board Schematic
12
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LM4970
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SNVS312D – JANUARY 2005 – REVISED MAY 2013
Demonstration Board NHK PCB Layout
Figure 16. Recommended NHK PCB Layout:
Top Silkscreen
Figure 17. Recommended NHK PCB Layout:
Top Layer
Figure 18. Recommended NHK PCB Layout:
Bottom Layer
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LM4970
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Revision History
Rev
Date
Description
1.1
5/26/06
On Table 2 (pg 8), col D7 for Pattern Select, changed the '1' into '0'.
1.2
04/01/08
Added the last paragraph under the AUDIO SYNCHRONIZATION MODE.
D
05/03/13
Changed layout of National Data Sheet to TI format.
14
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM4970SD/NOPB
ACTIVE
WSON
NHK
14
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 85
L4970
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of