Specifications

ESS Technology, Inc. SAM0023-122898 27

ES1869 DATA SHEET

ANALOG DESIGN CONSIDERATIONS

This section describes design considerations related to

inputs and outputs of analog signals and related pins on

the chip.

Game Port

The game port address 201h is decoded for timer pins TA,

TB, TC, and TD, and switch pins SWA, SWB, SWC, and

SWD. The MIDI serial input and output also come from the

game port connector in most applications.

Reference Generator

Reference generator pin CMR is shown bypassed to

analog ground.

Figure 18 Reference Generator Pin Diagram

Switch-Capacitor Filter

The outputs of the FOUT_L and FOUT_R filters must be

AC-coupled to the inputs CIN_L and CIN_R. This provides

for DC blocking and an opportunity for low-pass filtering

with capacitors to analog ground at these inputs.

Figure 19 Switch-Capacitor Filter Pin Diagram

Audio Inputs and Outputs

Analog inputs MIC, LINE_L, LINE_R, AUXA_L, and

AUXA_R should be capacitively coupled to their

respective input signals. All have pull-up resistors to CMR.

ES1869 analog outputs AOUT_L and AOUT_R should be

AC-coupled to an amplifier, volume control potentiometer,

or line-level outputs.

ES1869

CMR

47 µF

.1 µF

ES1869

FOUT_L

CIN_L

.22 µF

FOUT_R

CIN_R

680 pF