BL34018 Ver la hoja de datos (PDF) - Shanghai Belling Co., Ltd.
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BL34018 Datasheet PDF : 16 Pages
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BL34018
SWITCHING TIME
The switching times of the speakerphone circuit depends not only on the various external
components, but also on the operating conditions of the circuit at the time a change is to take
effect. For example, the switching time from idle to transmit is generally quicker than the
switching time from receive to transmit ( or transmit to receive).
The components which most significantly affect the timing between the transmit and receive
modes are those at Pins 5 (transmit turn-on), 6 (transmit turn-off), 7 (receive turn-on), and 8
(receive turn-off). These four timing functions are not independent, but interactive since the Tx-Rx
comparator operates on a RELATIVE Tx-Rx comparison, rather than on absolute values. The
components at Pins 11, 12, 13 and 23 affect the timing from the transmit mode to the idle mode.
Timing from the idle mode to transmit mode is relatively quick ( due to the quick charging of the
various capacitors), and is not greatly affected by the component values. Pins 5-8 do not affect the
idle-to-transmit timing since the Tx-Rx comparator must already be in the transmit mode for this
to occur.
The following table provides a summary of the effect on the switching time of the various
components, including the volume control:
Components
Tx to Rx
Rx to Tx
Tx to Idle
RC @ Pin 5
Moderate
Significant
No Effect
RC @ Pin 6
Significant
Moderate
No Effect
RC @ Pin 7
Significant
Moderate
No Effect
RC @ Pin 8
Moderate
Significant
No Effect
RC @ Pin 11
No Effect
Slight
Moderate
C @ Pin 12
No Effect
Slight
Significant
RC @ Pin 13
No Effect
Slight
Slight
RC @ Pin 23
No Effect
Slight
Significant
V@ Pin 24
No Effect
Moderate
No Effect
C@ Pin 25
Moderate
Moderate
Slight
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Total 16 Pages
8/15/2006
Wrote by 2006
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