LNBH25 STMicroelectronics, LNBH25 Datasheet - Page 9

• Manufacturer Part Number: LNBH25
• Description: LNB supply and control IC with step-up and I2C interface
• Manufacturer: STMicroelectronics

LNBH25
2.13
2.14
2.15
2.16
2.17
2.18
TDET: 22 kHz tone detection
When a 22 kHz tone presence is detected on the DETIN pin, the TDET I²C bit is set to “1”.
IMON: minimum output current diagnostic
In order to detect the output load absence (no LNB connected on the bus or cable not
connected to the IRD) the LNBH25 is provided with a minimum output current flag by the
IMON I²C bit, accessible in read mode, which is set to “1” if the output current is lower than
12 mA (typ.). It is recommended to use IMON function only with the 22 kHz tone
transmission deactivated, otherwise the IMON bit could be set to “0” even if the output
current is below the minimum current threshold. To activate IMON diagnostic function, set to
“1” the EN_IMON I²C bit in the DATA 4 register. Be aware that as soon as the IMON function
is activated by means of EN_IMON=1, the V
independently on the VSEL bit setting. This operation is applied in order to be sure that the
LNBH25 output has the higher voltage present in the LNB bus. Do not use this function in an
application environment where 21 V voltage level is not supported by other peripherals
connected to the LNB bus.
PDO: overcurrent detection on output pull-down stage
When an overcurrent occurs on the pull-down output stage due to an external voltage
source greater than LNBH25 nominal V
ms typ.), the PDO I²C bit is set to “1”. This may happen due to an external voltage source
present on the LNB output (V
For current threshold and deglitch time details, see
Power-on I²C interface reset and undervoltage lockout
The I²C interface built into LNBH25 is automatically reset at power-on. As long as the V
stays below the undervoltage lockout (UVLO) threshold (4.7 V typ.), the interface does not
respond to any I²C command and all DATA register bits are initialized to zeroes, therefore
keeping the power blocks disabled. Once the V
becomes operative and the DATA registers can be configured by the main microprocessor.
PNG: input voltage minimum detection
When input voltage (V
the PNG I²C bit is set to “1” and the FLT pin is set low. Refer to
ISW: inductor switching current limit
In order to allow low saturation current inductors to be used, the maximum DC-DC inductor
switching current limit threshold can be set by means of one I²C bit (ISW). Two values are
available: 2.5 A typ. (with ISW = 1) and 4 A typ. (with ISW = 0).
CC
pin) is lower than LPD (low power diagnostic) minimum thresholds,
OUT
Doc ID 022433 Rev 4
pin).
OUT
and for a time longer than I
OUT
CC
is immediately increased to 21 V (typ.)
rises above 4.8 V typ. the I²C interface
Table 13
.
Table 13
Application information
SINK_TIME-OUT
for threshold details.
(10
CC
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