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RT8576
High Voltage 8-CH LED Driver
General Description
Features
The RT8576 is an 8-CH LED driver capable of delivering
120mA for each channel. The RT8576 is a current mode
boost converter with an adjustable switching frequency
via the OSC pin from 100kHz to 1MHz and a wide VIN
range from 9V to 28V.
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The PWM output voltage loop selects and regulates the
LED pin with the highest voltage string to 0.6V, hence
allowing voltage mismatches between LED strings. The
RT8576 automatically detects and disconnects any
unconnected and/or broken strings during operation from
PWM loop to prevent VOUT from over voltage.
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The 3% matched LED currents on all channels are simply
programmed with a resistor. A very high contrast ratio true
digital PWM dimming can be achieved by driving the PWM
pin with a PWM signal.
When an abnormal situation (open/short/thermal) occurs,
a state signal will be sent to the system to shut down the
IC.
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Wide Input Supply Voltage Range : 9V to 28V
Adjustable Boost Controller Switching Frequency
from 100kHz to 1MHz
Programmable Channel Current
Channel Current Matching : ±3%
External Dimming Control
Boost MOSFET Over Current Protection
Automatic LED Open/Short Protection to Avoid
Output Over Voltage
VIN Under Voltage Lockout
Adjustable Over Voltage Protection
Under Voltage Protection
Thermal Shutdown Protection
Abnormal State Indicator for Open/Short/Thermal
Condition
RoHS Compliant and Halogen Free
Applications
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LCD TV, Monitor Display Backlight
LED Driver Application
General Purpose Constant Current Source
The RT8576 is available in TSSOP-24 (Exposed Pad) and
SOP-24 packages.
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Ordering Information
Marking Information
RT8576
RT8576GCP
Package Type
CP : TSSOP-24 (Exposed Pad)
S : SOP-24
Lead Plating Systeme
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
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RoHS compliant and compatible with the current require-
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RT8576GCP : Product Number
RT8576
GCPYMDNN
YMDNN : Date Code
RT8576GS
RT8576GS : Product Number
RT8576
GSYMDNN
YMDNN : Date Code
ments of IPC/JEDEC J-STD-020.
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Suitable for use in SnPb or Pb-free soldering processes.
DS8576-00 April 2011
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RT8576
Pin Configurations
(TOP VIEW)
PWM
OUT1
OUT2
OUT3
OUT4
GND
OUT6
OUT7
OUT8
OUT5
OVS
ISET
STATE
NC
COMP
NC
SS
VIN
PGND
VCCA
EXT
CS
EN
OSC
24
2
23
3
22
4
21
5
20
GND
6
7
19
18
8
17
9
16
10
15
25
11
12
14
13
PWM
OUT1
OUT2
OUT3
OUT4
GND
OUT8
OUT6
OUT7
OVS
ISET
OSC
24
TSSOP-24 (Exposed Pad)
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
STATE
NC
COMP
NC
SS
VIN
PGND
VCCA
EXT
OUT5
CS
EN
SOP-24
Typical Application Circuit
VIN
9 to 28V
L1
10µH
D1
CIN
47µF
VIN
CVIN
1µF
ROVP1
82k
RT8576
:
:
: …… :
:
:
:
:
:
:
:
:
:
:
: …… :
:
:
:
:
COUT
4.7µF x 8
OUT1
RF
100
CS
CF
1nF
RSENSE
ROVP2
3.6M
……
MSW
OVS
VOUT
45V
OUT4
OUT5
OUT6
EXT
5
……
REXT
OUT8
PWM Signal
Chip Enable
1k
1k
RSTATE
100k
PWM
EN
STATE
ISET
OSC
RC
560
CC1
0.22µF
CC2
NC
SS
COMP
RISET
4.53k
VIN
FLT
ROSC 56k
CSS 0.1µF
CREG 1µF
VCCA
PGND
GND
Figure 1. General Application
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DS8576-00 April 2011
RT8576
FLT
VIN
9 to 28V
L1
10µH
D1
VOUT
45V
CIN
47µF
CVIN
1µF
VIN
RT8576
:
:
:
:
:
:
: …… :
:
:
:
:
:
:
: …… :
:
:
:
:
OUT1
RF
100
CS
CF
1nF
RSENSE
ROVP1
82k
COUT
4.7µF x 8
……
MSW
OVS
ROVP2
3.6M
OUT4
OUT5
OUT6
EXT
5
OUT8
PWM Signal
Chip Enable
RC
560
CC1
0.22µF
……
REXT
CC2
NC
1k
1k
PWM
EN
STATE
ISET
OSC
COMP
RSTATE
100k
SS
VIN
FLT
RISET
4.53k
ROSC 56k
CSS 0.1µF
CREG 1µF
VCCA
PGND
GND
Figure 2. External P-MOSFET Isolation Application
DS8576-00 April 2011
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RT8576
Functional Pin Description
Pin No.
TSSOP-24
SOP-24
(Exposed Pad)
Pin Name
1
1
PWM
2, 3, 4, 5
2, 3, 4, 5
6,
25 (Exposed
Pad)
6
10, 7, 8, 9
15, 8, 9, 7
11
10
OVS
12
11
ISET
13
12
OSC
14
13
EN
OUT1 to
OUT4
GND
OUT5 to
OUT8
Pin Function
Digital Dimming Control. Connect a pull high or pull low resistor from
this pin to ground.
Channel 4 to Channel 1 LED Current Sink. Leave the pins
unconnected if not used.
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
Channel 8 to Channel 5 LED Current Sink. Leave the pins
unconnected if not used.
Over Voltage and Under Voltage Protection. PWM boost converter
turns off when VOVP or VUVP goes higher than 1.2V or lower than
0.6V, respectively.
LED Current Setting Pin. A resistor or a current from DAC on this pin
programs the full LED current.
Switching Frequency Setting Pin. Connect a resistor between OSC
and GND to set the boost converter switching frequency.
Chip Enable. When EN is pulled low, chip will be in shutdown mode.
Current Sense Input. During normal operation, this pin senses the
voltage across the external inductor current sensing resistor for peak
current mode control and is also used to limit the inductor current
during every switching cycle.
Boost Converter Power Switch Gate Output. This pin drives the
external power N-MOSFET device.
1μF capacitor should be placed on this pin to stabilize the 5V output
of the internal regulator. This regulator is for chip internal use only.
15
14
CS
16
16
EXT
17
17
VCCA
18
18
PGND
19
19
VIN
20
20
SS
21, 23
21, 23
NC
No Internal Connection.
22
22
COMP
PWM Boost Converter Loop Compensation Node.
24
24
STATE
Boost Converter Operation State Output.
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Boost Converter Power Ground.
Power Supply of the Chip. For good bypass, a low ESR capacitor
placed close to the pin is required.
Soft-Start Pin. Place a capacitor of at least 10nF from this pin to GND
to set the soft-start time period.
DS8576-00 April 2011
RT8576
Function Block Diagram
EXT CS
OSC
OSC
VIN
OVP
-
UVLO
UVP
OTP
S
+
R
OVS
+
1.2V
R
LED Short
+
OUT1
UVP
+
-
EN
-
5V
LDO
COMP
Shutdown
+
+
-
1.2V
5V
OUT8
VOUT
Regulation
Unit
6µA
…………………
0.6V
VCCA
STATE
+
-
+
SS
-
GND
PGND
PWM
DS8576-00 April 2011
ISET
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RT8576
Absolute Maximum Ratings
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(Note 1)
Supply Voltage, VIN , STATE -------------------------------------------------------------------------------------------- 33V
LED1 to LED8 --------------------------------------------------------------------------------------------------------------- 50V
PWM, EN, EXT, CS, SS, COMP, OSC, VCCA, OVS, ISET ----------------------------------------------------- 5.5V
Power Dissipation, PD @ TA = 25°C
TSSOP-24 (Exposed Pad) ----------------------------------------------------------------------------------------------- 2.500W
SOP-24 ----------------------------------------------------------------------------------------------------------------------- 1.111W
Package Thermal Resistance (Note 2)
TSSOP-24 (Exposed Pad), θJA ----------------------------------------------------------------------------------------- 40°C/W
TSSOP-24 (Exposed Pad), θJC ---------------------------------------------------------------------------------------- 7°C/W
SOP-24 , θJA ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 90°C/W
Junction Temperature ------------------------------------------------------------------------------------------------------ 150°C
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
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(Note 4)
Supply Voltage, VIN -------------------------------------------------------------------------------------------------------LED1 to LED8 --------------------------------------------------------------------------------------------------------------Junction Temperature Range --------------------------------------------------------------------------------------------Ambient Temperature Range ---------------------------------------------------------------------------------------------
9V to 28V
45V
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(VIN = 12V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Supply Voltage
Supply Current
I VIN
Switching Off
--
5
--
mA
Shutdown Current
I SHDN
VEN < 0.7V
--
--
10
μA
VDD LDO Output
VCCA
--
5
--
V
VDD LDO Capability
I VCCA
30
--
--
mA
VIN UVLO Threshold
VUVLO
VIN Rising
--
--
8
Hysteresis
--
1.4
--
Logic-High
EN Input
Threshold Voltage Logic-Low
VENH
1.5
--
--
VENL
--
--
0.8
114
120
126
mA
--
1.5
3
%
--
0.6
--
V
V
V
LED Current Programming
LED Current Accuracy
RISET = 4.53kΩ, VPWM > 1.2V
RISET = 4.53kΩ, VPWM > 1.2V
LED Current Matching
I(MAX) − I(MIN)
2 × I(Avg)
LED1 to LED8 Regulation Voltage
× 100%
I LED = 120mA
To be continued
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DS8576-00 April 2011
RT8576
Parameter
Symbol
VLED Threshold
Test Conditions
No Connection
ISET Pin Voltage
Min
Typ
Max
Unit
--
0.1
--
V
--
1.2
--
V
Dimming
Logic-High
VPWMH
1.2
--
--
Logic-Low
VPWML
--
--
0.4
ROSC = 24kΩ
--
1
--
MHz
ROSC = Open
--
100
--
kHz
--
100
--
ns
80
--
-0.5
---
%
V
Gate Driver Source
--
2.5
--
A
Gate Driver Sink
--
3
--
A
PWM Input
Threshold Voltage
V
PWM Boost Controller
Switching Frequency
fOSC
Minimum On Time
tON
Maximum Duty Cycle
CS Current Sense Limit
Dmax
Input Current Limit
OVP, UVP, SCP, OTP and Soft-Start
OVP Threshold
VOVP
1.1
1.2
1.3
V
UVP Threshold
VUVP
0.57
0.6
0.63
V
SCP Threshold
VSCP
LED1 to LED8
--
4.3
--
V
Soft-Start Current
ISS
VSS < 2.5V
--
6
--
μA
Thermal Shutdown Temperature
TSD
Lockout Temperature Point
--
150
--
°C
Thermal Shutdown Hysteresis
ΔTSD
Resume Temperature Point
--
20
--
°C
STATE Low Voltage
VSTATE
Open Drain at 10mA
--
--
0.5
V
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2. For TSSOP-24 (Exposed Pad), θJA is measured in natural convection at TA = 25°C on a high-effective thermal conductivity
test board of JEDEC 51-7 thermal measurement standard. For SOP-24 θJA is measured in natural convection at TA =
25°C on a low-effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The measurement
case position of θJC is on the exposed pad of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
DS8576-00 April 2011
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RT8576
Typical Operating Characteristics
LED Current vs. Input Voltage
100
LED Current vs. PWM Duty Cycle
60
96 LEDs
50
LED Current (mA)
80
LED Current (mA)
96 LEDs
60
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
40
20
PWM = 200Hz
PWM = 1kHz
PWM = 10kHz
40
30
20
10
VIN = 12V, RISET = 9.1kΩ
RISET = 9.1kΩ
0
0
8
10
12
14
16
18
20
22
24
26
0
28
20
30
40
50
60
70
80
90
100
Duty Cycle (%)
Input voltage (V)
Power On from VIN
Efficiency vs. Input Voltage
100
10
96 LEDs
Efficiency (%)
95
90
VIN
(5V/Div)
85
DRV
(5V/Div)
80
75
RISET = 9.1kΩ
I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF
70
8
10
12
14
16
18
20
22
24
26
Time (10ms/Div)
28
Input voltage (V)
Power On from PWM
Power On from VEN
PWM
(2V/Div)
VEN
(2V/Div)
DRV
(5V/Div)
DRV
(5V/Div)
I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF
Time (10ms/Div)
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I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF
Time (10ms/Div)
DS8576-00 April 2011
RT8576
Application information
The RT8576 is an 8-CH driver controller that delivers well
matched LED current to each channel of LED strings. The
external N-MOSFET current source will accommodate the
power dissipation difference among channels resulting from
the forward voltage difference between the LED strings.
With high speed current source N-MOSFET drivers, the
RT8576 features highly accurate current matching, while
also providing very fast turn-on and turn-off times. This
allows a very narrow minimum on or off pulse. The RT8576
integrates adjustable switching frequency and soft-start
and provides circuitry for over temperature, over voltage,
under voltage and current limit protection.
Soft-Start
The RT8576 employs a soft-start feature to limit the inrush
current. The soft-start circuit prevents excessive inrush
current and input voltage droop. The soft-start time is
determined by a capacitor, CSS, connected between SS
and GND and charged with a 6μA constant current as shown
in the following equation.
tSS (max) = CSS x 4 x 105 (s)
The value of capacitor CSS is user-defined to satisfy the
designer' requirement.
Compensation
The regulator loop can be compensated by adjusting the
external components connected to the COMP pin. The
COMP pin is the output of the internal error amplifier. The
compensation capacitor will adjust the zero to maintain
stability and the resistor value will adjust the compensator
gain for fast transient response. Typical values of the
compensation components are RC = 560Ω, CC = 0.22μF.
LED Connection
The RT8576 equips 8-CH LED drivers and each channel
supports up to 15 LEDs. The LED strings are connected
from the output of the boost converter to pin OUTx (x = 1
to 8) respectively. If one of the LED channel is not in use,
the OUTx pin should be opened directly.
Setting and Regulation of LED current
The LED current can be calculated by the following
equation :
543.6
RISET
where RISET is the resistor between the ISET pin and GND.
This setting is the reference for the LED current at pin
OUTx and represents the sensed LED current for each
string. The DC/DC converter regulates the LED current
according to the setting.
ILED ≅
Over Voltage and Under Voltage Protection
The RT8576 integrates Over Voltage Protection (OVP) and
Under Voltage Protection (UVP). When the voltage at the
OVS pin rises above the threshold voltage of approximately
1.2V or falls below the threshold voltage of approximately
0.6V, the internal switch will be turned off and the STATE
pin will be pulled high. The internal switch will be turned
on again once the voltage at the OVS pin returns to normal
range. The output voltage can be clamped at a certain
voltage level and can be calculated by the following
equations :
⎛
⎞
R
VOUT(OVP) = VOVP × ⎜ 1 + OVP2 ⎟
ROVP1 ⎠
⎝
⎛
⎞
R
VOUT(UVP) = VUVP × ⎜ 1 + OVP2 ⎟
ROVP1 ⎠
⎝
where ROVP1 and ROVP2 are the resistors in the resistive
voltage divider connected to the OVS pin. If at least one
string is in normal operation, the controller will
automatically ignore the open strings and continue to
regulate the current for the strings in normal operation.
Suggested value for ROVP2 is up to 3MΩ to prevent loading
effect.
LED Short Circuit Protection
The RT8576 integrates LED Short Circuit Protection (SCP).
If one of the OUT1 to OUT8 pin voltages exceeds a
threshold of approximately 4.3V during normal operation,
the STATE pin will be pulled high for a fault signal.
STATE
After the IC is enabled. STATE will output logic high if
LED short/OVP/UVP/OTP conditions exist. STATE will
be reset after VIN or EN is re-applied.
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RT8576
Setting the Switching Frequency
The RT8576 switching frequency is programmable from
100kHz to 1MHz by adjusting the oscillator resistor, ROSC.
The switching frequency can be calculated by the following
equation :
21.6 × 109
fSW ≅ 100k +
ROSC
Current Limit Protection
2
L=
D × (1 − D ) × VOUT
2 × f × IOUT
The duty cycle can be calculated as the following
equation :
D=
VOUT − VIN
VOUT
where VOUT is the maximum output voltage, VIN is the
minimum input voltage, f is the operating frequency, and
The RT8576 can sense the RSENSE voltage between the
CS pin and GND to achieve over current protection. The
boost converter senses the inductor current during the on
period. The duty cycle depends on the current signal and
internal slope compensation compared with the error
signal. The external switch will be turned off when the
current signal is larger than the internal slope
compensation. In the off period, the inductor current will
decrease until the internal switch is turned on by the
oscillator. The current limit value can be calculated by the
following equation :
0.5V
Current Limit (A) ≅
RSENSE
IOUT is the sum of current from all LED strings.
Brightness Control
Diode Selection
The RT8576 features a digital dimming control scheme. A
very high contrast ratio true digital PWM dimming is
achieved by driving the PWM pin with a PWM signal. The
recommended PWM frequency is 200Hz to 10kHz, but
the LED current cannot be 100% proportional to duty cycle,
especially for high frequency and low duty ratio.
Schottky diodes are recommended for most applications
because of their fast recovery time and low forward voltage.
Power dissipation, reverse voltage rating, and pulsating
peak current are important parameters for consideration
when making a Schottky diode selection. Make sure that
the diode's peak current rating exceeds IPEAK and reverse
voltage rating exceeds the maximum output voltage.
The boost converter operates in DCM over the entire input
voltage range when the inductor value is less than this
value, L. With an inductance greater than L, the converter
operates in CCM at the minimum input voltage and may
be discontinuous at higher voltages.
The inductor must be selected with a saturated current
rating that is greater than the peak current as provided by
the following equation :
IPEAK =
VOUT × IIOUT VIN × D × T
+
η × VIN
2×L
where η is the efficiency of the power converter.
Over Temperature Protection
The RT8576 has over temperature protection function to
prevent the IC from overheating due to excessive power
dissipation. The IC will shut down and the STATE pin will
be pulled high when junction temperature exceeds 150°C.
Main converter starts switching after junction temperature
cools down by approximately 20°C.
Capacitor Selection
Inductor Selection
It is recommended to choose a ceramic capacitor based
on the output voltage ripple requirements. The minimum
value of the output capacitor, COUT, can be calculated by
the following equation :
The value of the inductance, L, can be approximated by
the following equation, where the transition is from
Discontinuous Conduction Mode (DCM) to Continuous
Conduction Mode (CCM) :
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The input capacitor reduces current spikes from the input
supply and minimizes noise injection to the converter. For
general applications, six to eight 4.7μF ceramic capacitors
are sufficient. A value higher or lower may be used
depending on the noise level from the input supply and
the input current to the converter.
COUT =
IOUT × D
ΔVOUT × f
DS8576-00 April 2011
RT8576
Maximum Power Dissipation (W)1
where ΔVOUT is the peak-to-peak ripple voltage at the
output.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ (MAX) − TA) / θJA
where TJ (MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT8576, the maximum junction temperature is 125°C
and TA is the ambient temperature. The junction to ambient
thermal resistance, θJA, is layout dependent. For TSSOP24 (Exposed Pad) packages, the thermal resistance, θJA,
is 40° C/W on a standard JEDEC 51-7 four-layer thermal
test board. For SOP-24 packages, the thermal resistance,
θJA , is 90°C/W on a standard JEDEC 51-3 single-layer
thermal test board. The maximum power dissipation at TA
= 25°C can be calculated by the following formula :
1.0
0.8
SOP-24
0.6
0.4
0.2
0.0
25
50
75
100
125
Figure 3. Derating Curve for RT8576 Packages
Layout Considerations
Careful PCB layout is very important for designing
switching power converter circuits. The following layout
guidelines should be strictly followed for best performance
of the RT8576.
`
The power components L1, D1, CIN, COUT must be placed
as close as possible to the IC to reduce current loop.
The PCB trace between power components must be as
short and wide as possible.
`
The compensation circuit should be kept away from
the power loops and shielded with a ground trace to
prevent any noise coupling. Place the compensation
components, RC and CC, as close as possible to pin
22.
`
The exposed pad of the chip should be connected to
ground plane for thermal consideration.
PD(MAX) = (125°C − 25°C) / (90°C/W) = 1.111W for
DS8576-00 April 2011
1.4
1.2
Ambient Temperature (°C)
TSSOP-24 (Exposed Pad) package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. For the RT8576 packages, the derating
curves in Figure 3 allow the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
TSSOP-24 (Exposed Pad)
1.8
1.6
0
PD(MAX) = (125°C − 25°C) / (40°C/W) = 2.500W for
SOP-24 package
2.6
2.4
2.2
2.0
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RT8576
The compensation circuit should be kept away from the power loops
and shielded with a ground trace to prevent any noise coupling.
PWM
OUT1
OUT2
OUT3
OUT4
GND
OUT6
OUT7
OUT8
OUT5
OVS
ISET
24
2
23
3
22
4
21
5
20
GND
6
7
19
18
8
17
9
16
10
11
15
25
14
12
13
Locate the CVIN
as close to VIN
STATE CC2
as possible.
NC
COMP
RC CC1 COUT
NC
SS
VOUT
VIN
PGND CVIN
D1
VIN
VCCA
L1
EXT
CS
REXT
EN
Msw C
IN
OSC
RF
RSENSE
CF
RGND
PGND
GND
Place the power components as close to the IC As possible.
The traces should be wide and short especially for the high
current loop.
Figure 4. TSSOP-24 (Exposed Pad) PCB Layout Guide
The compensation circuit should be kept away from the power loops
and shielded with a ground trace to prevent any noise coupling.
PWM
OUT1
OUT2
OUT3
OUT4
GND
OUT8
OUT6
OUT7
OVS
ISET
OSC
24
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
STATE
NC
COMP
NC
SS
VIN
PGND
VCCA
EXT
OUT5
CS
EN
CC2
GND Locate the CVIN
as close to VIN
as possible.
RC CC1 COUT
VOUT
CVIN
L1
VIN
REXT
Msw CIN
RF
RGND
D1
CF
RSENSE
GND
PGND
Place the power components as close to the IC As possible.
The traces should be wide and short especially for the high
current loop.
Figure 5. SOP-24 PCB Layout Guide
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DS8576-00 April 2011
RT8576
Outline Dimension
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
1.000
1.200
0.039
0.047
A1
0.000
0.150
0.000
0.006
A2
0.800
1.050
0.031
0.041
b
0.190
0.300
0.007
0.012
D
7.700
7.900
0.303
0.311
e
0.65
0.026
E
6.300
6.500
0.248
0.256
E1
4.300
4.500
0.169
0.177
L
0.450
0.750
0.018
0.030
U
3.700
4.900
0.146
0.193
V
2.200
3.100
0.087
0.122
24-Lead TSSOP (Exposed Pad) Plastic Package
DS8576-00 April 2011
www.richtek.com
13
RT8576
H
A
M
B
J
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
15.189
15.596
0.598
0.614
B
7.391
7.595
0.291
0.299
C
2.362
2.642
0.093
0.104
D
0.330
0.508
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.229
0.330
0.009
0.013
I
0.102
0.305
0.004
0.012
J
10.008
10.643
0.394
0.419
M
0.381
1.270
0.015
0.050
24–Lead SOP Plastic Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
5F, No. 95, Minchiuan Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
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DS8576-00 April 2011