REV. 0

EVAL-AD1852EB

–4–

• U8 (ADM811TART) is a RESET generator that provides

a debounced 200 ms reset signal from the push button (S3)

or on power up. The reset is active if the 5 V supply drops

below 3 V.

• U7 (AD3303-5.0) is a low noise 5 V dc regulator for the ana-

log section of the AD1852.

• U9 (OP275) is a low noise and distortion, audio op amp. U9

provides differential-to-single-ended conversion and a low-

pass anti-image filter. A third order low-pass Bessel filter

response is implemented with a –3 dB corner frequency of

100 kHz and a 60 dB/decade roll-off. This type of filter is

characterized by a linear phase response and fast transient

response without overshoot.

• U10 (74HC00) is used to provide a reset code to the digital

interface receiver (U2), pins M0–3, at power up and also sends

the correct interface code to ensure the digital output for-

mat matches the input of the DAC.

• U11 (74HC00) is used to select the correct master clock

source for the DAC when it is switched between the SPDIF

receiver (U2) and the Ext Data Interface (J2). A discrete logic

gate is used for this function, because of the excessive jitter

that modulates high-frequency clock signals when they are

handled by PLDs.

PERFORMANCE SPECIFICATIONS

Typical performance, for a sample rate of 48 kHz, is tabulated

below.

1. SNR, A-Weighted

–114 dBFS

± 1 dB

2. DNR, A-Weighted

–114 dBFS

± 1 dB

3. THD+N

–102 dBFS

± 2 dB

4. Frequency Response

±0.2 dB, 10 Hz to 20 kHz

5. Noise Floor

–145 dBFS

6. Full-Scale Audio Output

2 V rms

ATTACHMENTS

The following is included for your convenience.

• Appendix A: ABEL Source Code for Vantis MACH4-64/32

CPLD.

• Appendix B: Set of Schematics, Figures 1 and 2.

• Appendix C: PCB plots showing the silkscreen layer, top

signal layer, ground planes, power planes, and the bottom

signal layer, Figures 3–7.

FURTHER INFORMATION

Ordering information: order number is EVAL-AD1852EB.

For application questions, please contact our Central Applica-

tions Department at 1-781-937-1428 for assistance.