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PDF RT5047 Data sheet ( Hoja de datos )
| Número de pieza | RT5047 | |
| Descripción | Single Output LNB Supply and Control Voltage Regulator | |
| Fabricantes | Richtek | |
| Logotipo |  |
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RT5047
Single Output LNB Supply and Control Voltage Regulator
General Description
The RT5047 is a highly integrated voltage regulator
and interface IC, specifically design for supplying
power and control signals from advanced satellite
set-top box (STB) modules to the LNB down-converter
in the antenna dish or to the multi-switch box.
The device is consists of the independent current-mode
boost controller and low dropout linear regulator along
with the circuitry required for 22KHz tone shaping to
support DiSEqCTM1.x communications.
The RT5047 has fault protection (over-current,
over-temperature and under-voltage lockout).
The RT5047 are available in a SOP-8 (Exposed Pad)
package to achieve optimized solution for thermal
dissipation.
Ordering Information
RT5047
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current
requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering
processes.
Features
Wide Input Supply Voltage Range : 8V to 16V
Output Current Limit of 550mA with 45ms timer
Low Noise LNB Output Voltage (13.3V and 18.3V
by SEL Pin)
3% High Accuracy for 0mA to 500mA Current
Output
Push-Pull Output Stage minimizes 13.3V to
18.3V and 18.3V to 13.3V Output Transition Time
External 22kHz Tone Input
Meet DiSEqCTM1.x Protocol
Output Short Circuit Protection
Over-temperature Protection
Applications
LNB Power Supply and Control for Satellite Set-Top
Box
Analog and Digital Satellite Receivers/ Satellite TV,
Satellite PC cards
Pin Configurations
(TOP VIEW)
LNB
BOOST
LX
VIN
8
27
GND
36
9
45
TONE
NC
SEL
EN
SOP-8 (Exposed Pad)
Simplified Application Circuit
L1
VIN
CIN1
CIN2
VIN
LX
D1
BOOST
EN
TONE
SEL
LNB
RT5047
GND
CBST
Max. 550mA
D2 CLNB
D3
VLNB
D4
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS5047-00 March 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
1 page  
RT5047
Parameter
Symbol
Test Conditions
Load Regulation
Line Regulation
Protection
VLNB = 13.3V, ILNB = 50mA to 450mA
VOUT_LOAD
VLNB = 18.3V, ILNB = 50mA to 450mA
VOUT_LINE
VIN = 9 to 14V, VLNB = 13.3V,
ILNB = 50mA
VIN = 9 to 14V, VLNB = 18.3V,
ILNB = 50mA
Output Over-Current Limit ILIM_LNB1
Output Over-Current
Disable Time
TDIS_ON
Output Over-Current
Disable Time
TDIS_OFF
VIN Under-Voltage Lockout
Threshold
VUVLO
VLNB = 13.3V/18.3V
VLNB Short to GND
VLNB Short to GND (GBD)
VIN Falling
VIN Turn On Threshold
VIN_TH
VIN Rising
VIN Under-Voltage Lockout
Hysteresis
VUVLOHYS
OTP Threshold
OTP Hysteresis
TONE
TOTP
TOTPHYS
TONE Frequency
TONE Amplitude, Peak to
Peak
TONE Duty Cycle
FTONE
VTONE_PP
DCTONE
ILNB = 50 to 450mA, CLNB = 200nF
ILNB = 0 to 450mA, CLNB = 570nF
TONE Rise Time
TRTONE
ILNB = 0 to 450mA, CLNB = 570nF
TONE Fall Time
TFTONE
ILNB = 0 to 450mA, CLNB = 570nF
TONE Logic Input
VTONE_H
VTONE_L
TONE Input Leakage
ITONELKG
ENABLE, SEL Pins
EN Logic Input
VEN_H
VEN_L
EN Input Leakage
IENLKG
SEL Logic Input
VSEL_H
VSEL_L
SEL Input Leakage
ISELLKG
Min Typ Max Unit
-- 38 76
mV
-- 45 90
-10 -- 10
mV
-10 -- 10
500 550 650 mA
-- 45 -- ms
-- 1800 --
ms
-- 7.35 --
-- 7.7 8
-- 350 --
-- 140 --
-- 15 --
V
V
mV
C
C
20 22 24 kHz
550 700 900 mVPP
40 50 60 %
5 10 15 s
5 10 15 s
1.2 -- -- V
-- -- 0.4 V
-- 5 10 A
1.2 -- -- V
-- -- 0.4 V
-- 5 10 A
1.2 -- -- V
-- -- 0.4 V
-- 5 10 A
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS5047-00 March 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
5 Page 
Application Information
Boost Converter/Linear Regulator
The 5047 integrates a current-mode boost converter
and linear regulator. Use the SEL pin to control the
LNB voltage and the boost converter track is at least
greater 800mV than the LNB voltage. The boost
converter is high efficiency PWM architecture with
700kHz operation frequency. The linear regulator has
the capability to source current up to 550mA during
continuous operation. All the loop compensation,
current sensing, and slope compensation functions are
provided internally.
The RT5047 has current limiting on the boost converter
and the LNB output to protect the IC against short
circuits. The internal MOSFET will turn off when the LX
current is higher than 3A cycle-by-cycle. The LNB
output will turn off when the output current higher than
the 550mA and 45ms and turn-on after 1800ms
automatically.
Input Capacitor Selection
The input capacitor reduces voltage spikes from the
input supply and minimizes noise injection to the
converter. A 30F capacitance is sufficient for most
applications. Nevertheless, a higher or lower value may
be used depending on the noise level from the input
supply and the input current to the converter. Note that
the voltage rating of the input capacitor must be greater
than the maximum input voltage.
Inductor Selection
The inductance depends on the maximum input current.
As a general rule, the inductor ripple current range is
20% to 40% of the maximum input current. If 40% is
selected as an example, the inductor ripple current can
be calculated according to the following equations :
IIN(MAX)
=
VOUT IOUT(MAX)
VIN
IRIPPLE = 0.4 IIN(MAX)
where η is the efficiency of the converter, IIN(MAX) is
the maximum input current, and IRIPPLE is the
inductor ripple current. The input peak current can
then be obtained by adding the maximum input current
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS5047-00 March 2015
RT5047
with half of the inductor ripple current as shown in the
following equation :
IPEAK = 1.2 x IIN(MAX)
note that the saturated current of the inductor must be
greater than IPEAK. The inductance can eventually be
determined according to the following equation :
L η VIN 2 VOUT VIN
0.4 VOUT 2 IOUT(MAX)fOSC
where fOSC is the switching frequency. For better
system performance, a shielded inductor is preferred to
avoid EMI problems.
Boost Output Capacitor Selection
The RT5047 boost regulator is internally compensated
and relies on the inductor and output capacitor value
for overall loop stability. The output capacitor is in the
30F to 50F range with a low ESR, as strongly
recommended. The voltage rating on this capacitor
should be in the 25V to 35V range since it is connected
to the boost VOUT rail.
The output ripple voltage is an important index for
estimating chip performance. This portion consists of
two parts. One is the product of the inductor current
with the ESR of the output capacitor, while the other
part is formed by the charging and discharging process
of the output capacitor. As shown in Figure 1, VOUT1
can be evaluated based on the ideal energy
equalization. According to the definition of Q, the Q
value can be calculated as the following equation :
Q=
1
2
IIN
1
2
IL
IOUT
IIN
1
2
IL
IOUT
VIN
VOUT
1
fOSC
= COUT VOUT1
where fOSC is the switching frequency and IL is the
inductor ripple current. Bring COUT to the left side to
estimate the value of VOUT1 according to the following
equation :
VOUT1
=
D IOUT
COUT fOSC
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet RT5047.PDF ] | |
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