Low -power audio DAC

block diagram

function description

System clock

UDA1334BTS

It only runs in the subordinate mode; this means that in all applications, the system must provide system clock and digital audio interface signal (BCK and WS) Essence

The system clock must lock the interface signal at the digital frequency.

UDA1334BTS automatic detection

Sysclk and WS frequency.

BCK clock can be as high as 64FS, that is,

BCK frequency is 64 times the word SELECT (WS): FBCK ≤ 64 × FWS.

Comment:

The edge of the WS must be used to always use BCK to ensure that the number I/O normal running data interface

There is a WS for LSB alignment format. Signals with a duty ratio of 50%.

Table 1 gives a support mode.

Table 1 The sampling range supported

This mode can only support the power supply voltage to 2.4V, for the lower one, for lower ones For voltage, the sampling frequency of IN192FS mode should be limited to 55 kg.

It is not supported in the low sampling frequency mode.

Table 2 gives an example of 12.228 MHz system input

Table 2 Example using 12.228 MHz system clock

Note

This mode can only support the voltage of the power supply to 2.4 types. 5. For lower voltage, the sampling frequency of 192FS should be limited to 55 kilo.

The interpolation filter interpolation Digital filter from 1FS to 64FS passes the class couplet FIR filter (see Table 3).

Table 3 Insert filter feature

Noise plastic surgery

Five -level noise plastic surgery works at 64FS. It has changed the frequency of quantified noise in the band is much higher than the vocal cords. This noise plastic surgery technology makes the signal -to -noise ratio to be achieved. The noise plastic surgery uses a filter DAC (FSDAC).

Filter DAC

FSDAC is a semi -digital reconstruction filter that converts 1 digit data of noise plastic surgery to analog output voltage. The filter coefficient is implemented as the current source, and summarizes the virtual ground of the output operation amplifier. At thisA very high signal -to -noise ratio and a low clock achieve a jitter sensitivity. Do not need a posterior filter, because DAC's inherent filtering function. The car amplifier converts the FSDAC output current to the signal that can drive the line output.

The output voltage of the FSDAC is zoomed in a power supply voltage in proportion.

Powering reset

UDA1334BTS has an internal power -power reset circuit (see Figure 3) resetting test control blocks.

resetting time (see Figure 4) connected from the outer pins VREF (DAC) and the ground. The reset time should be at least 1 microsecond VREF (DAC) lt; 1.25 V. When the VDDA is closed, if the device is VREF (DAC) LT; 0.75 V, it will be reset again. During the resetting time, the system clock should run.

Low -power audio DAC

Low -power audio DAC

System clock timing.

Serial interface timing.

Application information

Typical application diagram.

SSOP16: Plastic contraction to the appearance package; 16 lead; body width 4.4 mm

Welding

Introduction to welding surface installation

IC packaging without welding methods suitable for all surfaces. Summit welding is not always suitable for surface stickers integrated circuits or high population density. Welding is often used in these cases.

Reflowing welding backwing welding requires tin paste (a fine solder particles, welds, and adhesives) to allocate the pressure syringe before placing by the wire printing, template printing or packaging. There are several return methods; for example, infrared/convection heating in the transmitted oven. Different production hours (preheating, welding and cooling) are between 100 and 200 seconds, depending on the heating method.

Typical return peak temperature range is 215 to 250 ° C. The top surface temperature packaging is best kept below 230 ° C.

Peak welding

It is not recommended to use traditional single -wave welding for surface stickers (SMD) or printing circuit boards with high component density, such as welding bridges and non -humidity. It will bring major problems. In order to overcome these problems with dual -wave welding methods, it is specially developed.

If you use wave welding, you must meet the following conditions to obtain the best results: using dual -wave welding methods, including high -rise stress turbulent wave smooth layer of flow waves.

Packaging of lead and spacing (E) on both sides: - greater than or waitIn 1.27 mm, the longitudinal axis of the footprint is best parallel to the transport direction of the printing circuit board; - less than 1.27 mm, the footprint vertical axis must be with the printing circuit board.The footprint must include the downstream end of the welded thief.

For packaging with a lead on all sides, the package must be a 45 ° corner printing circuit board with the transport direction.Footprints must include welded thieves with downstream and corners.

Before placing and welding, the packaging must be fixed with a drop of adhesive.The adhesive can be printed, needle metastasis, or injections.The packaging can be curing up in a bindent.

At 250 ° C, the typical stay is 4 seconds.

The gentle and activated welding agent will eliminate the corrosion residues in most applications.

Manual welding first welding two components to diagonally diagonally.Use low pressure (24 V or less) soldiers to be applied to the flat part of the lead.

The contact time must not exceed 10 seconds and 300 degrees Celsius.