ucb1400 NXP Semiconductors, ucb1400 Datasheet - Page 23

• Manufacturer Part Number: ucb1400
• Description: Audio Codec With Touch Screen Controller And Power Management Monitor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 09611
Product data
9.2.3 Filter stream DAC
9.2.4 Headphone driver
The FSDAC is a semi-digital reconstruction filter that converts the 1-bit data stream of
the noise shaper to an analog output voltage. The filter coefficients are implemented
as current sources and are summed at virtual ground of the output operational
amplifier. In this way, very high signal-to-noise performance and low clock jitter
sensitivity is achieved. A post-filter is not needed due to the inherent filter function of
the DAC. On-board amplifiers convert the FSDAC output current to an output voltage
signal capable of driving a line output. The output voltage of the FSDAC scales
proportionally with the power supply voltage.
The headphone driver a reference output that acts as the virtual ground. This allows
direct connection to a stereo headphone without the use of external DC blocking
capacitors. The headphone driver is enabled when HPEN is set to ‘1’ in the
Feature Control/Status Register 1 (0x6A).
The headphone driver is equipped with a short circuit protection on each of the
LINE_OUT_L, LINE_OUT_R and VREFDRV output. When HPEN = 1, the short
circuit protection circuit will inform the user in case the limiter is activated, e.g., in
case of short circuit, by setting the corresponding bit (CLPL, CLPR or CLPG) in the
Extra Interrupt register (0x70). In addition, an interrupt is generated on the IRQOUT
pin of UCB1400 whenever the CLPP or CLPN bit is set in the Positive and/or
Negative INT Enable Registers. In that case, the CPLS bit will be set in the
INT Clear/Status register (index 0x62). The user can subsequently examine the
Extra Interrupt register (0x70) to determine the source of the short circuit.
Fig 16. Headphone connections.
Rev. 02 — 21 June 2002
UCB1400
Audio codec with touch screen controller
LINE_OUT_L
VREFDRV
LINE_OUT_R
and power management monitor
SN00228
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
UCB1400
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