Bill of Materials
This section lists all components required to assemble the Ma Bell Gateway. Values, part numbers, and notes are included for clarity.
Ref. Des. |
Description |
Value / Rating |
Manufacturer / Part # |
Notes |
|---|---|---|---|---|
U1 |
ESP32-WROVER-IE Module |
– |
Espressif ESP32-WROVER-IE |
Main MCU |
U2 |
SLIC, Line Interface IC |
HC-5504B (DIP-24) |
Intersil / Renesas HC-5504B-5 |
Subscriber Line Interface Circuit |
U3 |
DAC (Digital-to-Analog Converter) |
PCM5100PWR |
Texas Instruments |
TSSOP-20, I2S audio output |
U4 |
ADC (Analog-to-Digital Converter) |
PCM1808PWR |
Texas Instruments |
TSSOP-20, I2S audio input |
C_AUDIO1, C_AUDIO2 |
AC Coupling Capacitors (Audio) |
10µF, 16V+ |
Generic / Film or X7R MLCC |
Non-polarized, between codec and SLIC |
C_DAC1 |
Decoupling Capacitor (DAC) |
0.1µF ceramic |
Generic / X7R |
Near PCM5100 VDD pin |
C_DAC2 |
Bulk Capacitor (DAC) |
10µF tantalum/MLCC |
Generic / Low ESR |
Near PCM5100 VDD pin |
C_ADC1 |
Decoupling Capacitor (ADC) |
0.1µF ceramic |
Generic / X7R |
Near PCM1808 VDD pin |
C_ADC2 |
Bulk Capacitor (ADC) |
10µF tantalum/MLCC |
Generic / Low ESR |
Near PCM1808 VDD pin |
R_XSMT |
Pull-up Resistor (DAC Mute) |
10kΩ, 1% |
Generic / Metal film |
PCM5100 XSMT pin to 3.3V |
R_BIAS |
Input Bias Resistor (ADC) |
10kΩ, 1% |
Generic / Metal film |
PCM1808 VINL to AGND |
J1 |
RJ11 Jack |
6P4C or 6P2C |
Amphenol or equivalent |
Phone line output |
J2 |
Power Connector |
Barrel Jack, 5.5x2.1mm |
CUI PJ-102A or equivalent |
For 48V DC supply input (60W recommended) |
U5 |
Ring Generator IC |
LT1684 |
Analog Devices LT1684CN (DIP-16) |
Telephone ring tone generator |
K1 |
Ring Relay |
DPDT, 12V coil |
Omron G5V-2-H1-DC12 |
Switches line between -48V and ring generator |
Q1 |
Relay Driver Transistor |
2N2222A |
Generic / ON Semi PN2222A |
Drives ring relay coil from SLIC RD pin |
D1 |
Flyback Diode |
1N4148 |
Generic |
Across relay coil |
R_LED1, R_LED2 |
LED Current Limiting Resistors |
330Ω, 1/4W |
Generic / Metal film |
For 3.3V status LEDs (GPIO 2, 18) |
LED1, LED2 |
Status LEDs |
3mm or 5mm |
Generic (any color) |
Power/status indicators |
R_BASE |
Relay Driver Base Resistor |
1kΩ, 1/4W |
Generic / Metal film |
Q1 base current limiting |
C_DEC1-4 |
IC Decoupling Capacitors |
0.1µF ceramic |
Generic / X7R |
Near each IC VDD pin |
PS1 |
48V to 12V Buck Converter |
48V→12V, 1.5A |
DROK (Amazon) or LM2596HV module |
SLIC VB+ power |
PS2 |
12V to 3.3V Buck Converter |
12V→3.3V, 1A |
LM2596 module (3.3V fixed output) |
ESP32 and codec power |
PS3 |
-48V DC-DC Converter |
48V→-48V isolated |
TBD (see power-supply.rst) |
SLIC VB- loop voltage (deferred) |
Misc. |
PCB, hardware, headers, jumpers |
– |
– |
Enclosure, standoffs, screws, etc. |