RT5047 Просмотр технического описания (PDF) - Richtek Technology
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RT5047 Datasheet PDF : 16 Pages
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Table 1
SEL Pin Status
LNB Output Voltage
0
13.3V
1
18.3V
RT5047
Tone Generation
The RT5047 provides the tone generation function, please refer to the Figure 2. Set the TONE pin with 22kHz logic
signal, the LNB linear regulator output will carry a 22kHz, 700mV peak to peak signal for DiSEqC 1.x communication.
It can meet base-band timings of 500s (±100s) for a one-third bit PWK coded signal period on a nominal 22kHz
(±20 %).
LNB
TONE
signal
700m
V
VLNB output
TONE when
TONE signal
rise up
TONE signal
detect time
VLNB close
TONE after
TONE signal
detect time
13.3V or
18.3V
3.3V
0V
Figure 2. Tone Generation Options
Pull-Down Rate Control
The output linear stage provides approximately 40mA
of pull-down capability. This ensures that the output
volts are ramped from 18.3V to 13.3V in a reasonable
amount of time.
Over-Current Disable Time
If the LNB output current exceeds 550mA, typical, for
more than 45ms, then the LNB output will be disabled
and device enters a TON = 45ms/TOFF = 1800ms
routine. It will be returned to normal operation after a
successful soft-start process.
If loading is 1000mA
OCP1=1000mA
OCP1=1000mA
25ms
OCP2=550mA
20ms
1800ms
25ms
OCP2=550mA
20ms
If LNB is shorted to GND
OCP1=250mA
OCP1=250mA
25ms
OCP2=138mA
20ms
1800ms
25ms
OCP2=138mA
20ms
Inrush Current
At start-up or during a LNB reconfiguration event, a
transient surge current above the normal DC operating
level can be provided by the IC. This current increase
can be as high as 550mA, typical, for as long as
required, up to a maximum of 45ms.
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS5047-00 March 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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