component
MC34018G-S28-R
Public Made by Adomby adom
UTC(Unisonic Tech) Audio Power OpAmps, SOIC-28-300mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
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Datasheet
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README
markdownMC34018G-S28-R
UTC(Unisonic Tech) · Audio Power OpAmps · SOIC-28-300mil
MC34018G-S28-R from UTC(Unisonic Tech), in a SOIC-28-300mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | RR | passive | A resistor to ground provides a reference current for the transmit and receive attenuators. |
| 2 | RTX | passive | A resistor to ground sets the nominal transmit attenuator gain, which is inversely proportional to the RTX resistance. |
| 3 | TXI | input | Transmit attenuator input with nominal input resistance of 5.0kΩ. |
| 4 | TXO | output | Transmit attenuator output that drives the transmit level detector input and the external circuit driving the telephone line. |
| 5 | TLI | input | Transmit level detector input; an ac-coupled external resistor sets the detection level, and a smaller resistor increases sensitivity to transmit channel signals. |
| 6 | TLO | output | Transmit level detector output; external resistor and capacitor set the time the comparator holds transmit mode after speech ceases. |
| 7 | RLI | input | Receive level detector input; an ac-coupled external resistor sets the detection level, and a smaller resistor increases sensitivity to receive channel signals. |
| 8 | RLO | output | Receive level detector output; external resistor and capacitor set the time the comparator holds receive mode after speech ceases. |
| 9 | MCI | input | Microphone amplifier input with nominal input impedance of 10kΩ and dc bias approximately equal to VB. |
| 10 | MCO | output | Microphone amplifier output with internally set gain of 34dB (50V/V). |
| 11 | CP1 | passive | A parallel resistor and capacitor to VCC holds a voltage corresponding to the background noise level, which the transmit detector compares with the CP2 speech signal. |
| 12 | CP2 | passive | A capacitor at this pin peak detects speech signals for comparison with the background noise level held at CP1. |
| 13 | XDI | input | Input to the transmit detector system, ac coupled from the microphone amplifier output through an external resistor. |
| 14 | SKG | power_in | High current ground pin for the speaker amplifier output stage, to be within 10mV of the ground voltage at pin 22. |
| 15 | SKO | output | Speaker amplifier output that sources and sinks up to 100mA when ac coupled to the speaker, with internally set gain of 34dB (50V/V). |
| 16 | V+ | power_in | Input DC supply voltage, required 6.0V to 11V (7.5V nominal) at 7.0mA, which can be powered from Tip and Ring via an ac decoupling inductor. |
| 17 | AGC | passive | A capacitor to VB stabilizes the speaker amplifier gain control loop and sets its attack and decay time, with nominal internal resistance of 110kΩ. |
| 18 | CS | input | Digital chip select input: logic 0 (<0.7V) enables the VCC regulator, logic 1 (>1.6V) selects standby drawing 0.5mA, open is logic 0, input impedance about 140kΩ, and input must not exceed 11V. |
| 19 | SKI | input | Speaker amplifier input with nominal input impedance of 20kΩ. |
| 20 | VCC | power_out | 5.4V regulated output powering all circuits except the speaker amplifier output stage, up to 3.0mA for external circuitry, requires a filter capacitor. |
| 21 | VB | power_out | Output of approximately VCC/2 serving as analog ground, sourcing up to 1.5mA with 250 ohm output impedance, requires a filter capacitor. |
| 22 | GND | power_in | Ground pin for the IC except the speaker amplifier. |
| 23 | XDC | passive | Transmit detector output; a resistor and capacitor hold transmit mode during pauses, with nominal internal resistor of 2.6k ohms. |
| 24 | VLC | input | Volume control input for receive mode volume control from a variable resistor slider; voltage should be less than or equal to VB. |
| 25 | ACF | passive | Attenuator control filter; a capacitor here reduces noise transients when the attenuator switches attenuation level. |
| 26 | RXO | output | Receive attenuator output, normally ac coupled to the speaker amplifier input. |
| 27 | RXI | input | Receive attenuator input with nominal input resistance of 5.0kΩ. |
| 28 | RRX | passive | A resistor to ground sets the nominal receive attenuator gain, which is directly proportional to the RRX resistance. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | UTC(Unisonic Tech) |
| Package | SOIC-28-300mil |
| Category | Amplifiers |
| Pins | 28 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| V+ terminal voltage (pin 16) | V+ | -1 | 12 | V | TA=25C, referred to pin 22 | 5 | |
| CS (pin 18) voltage | CS | -1 | 12 | V | TA=25C, referred to pin 22 | 5 | |
| Speaker amplifier ground (pin 14) | SKG | -1 | 3 | V | TA=25C, referred to pin 22 | 5 | |
| VLC (pin 24) minimum voltage (maximum printed as +VCC) | VLC | -1 | V | TA=25C, referred to pin 22; upper limit +VCC | 5 | ||
| Storage temperature | TSTG | -65 | 150 | C | 5 | ||
| V+ terminal voltage (pin 16) | V+ | 6 | 11 | V | 5 | ||
| CS (pin 18) | CS | 0 | 11 | V | 5 | ||
| Receive signal (pin 27) | 0 | 250 | mVrms | 5 | |||
| Microphone signal (pin 9) | 0 | 5 | mVrms | 5 | |||
| Speaker amplifier ground (pin 14) | -10 | 10 | mVdc | 5 | |||
| ICC (pin 20) | ICC | 0 | 3 | mA | 5 | ||
| Ambient temperature | TA | -20 | 60 | C | 5 | ||
| VCC voltage | VCC | 4.9 | 5.4 | 5.9 | Vdc | V+=7.5V | 5 |
| Line regulation | VCCLN | 65 | 150 | mV | 6.5V<V+<11V | 5 | |
| Dropout voltage | VD | 80 | 300 | mV | V+=5.0V | 5 | |
| VB voltage | VB | 2.5 | 2.9 | 3.3 | Vdc | V+=7.5V | 5 |
| V+ supply current | IV+ | 9 | mA | V+=11V, Pin 18=0.7V | 5 | ||
| V+ supply current | IV+ | 800 | μA | V+=11V, Pin 18=1.6V | 5 | ||
| Output resistance | ROUT | 6 | 20 | Ω | ICC=3mA | 5 | |
| Receive attenuator gain | GRX | 2 | 6 | 10 | dB | 1.0kHz | 5 |
| Receive attenuator range (Rx to Tx modes) | GRX | 40 | 44 | 48 | dB | Rx Mode, Pin 24=VB, Pin 27=250mVrms | 5 |
| Receive attenuator idle mode gain | GRI | -20 | -16 | -12 | dB | Idle Mode, Pin 27=250mVrms | 5 |
| RXO voltage (Rx mode) | VRXO | 1.8 | 2.3 | 3.2 | mV | 6 | |
| Delta RXO voltage (switch from Rx to Tx mode) | VRXO | 100 | mV | 6 | |||
| RXO source current (Rx mode) | IROXH | 1 | 3 | mA | 6 | ||
| RXI input resistance | RRXI | 3.5 | 5 | 8 | kΩ | 6 | |
| Volume control range | VCR | 24.5 | 32.5 | dB | Rx Attenuator Gain, Rx Mode, 0.6VB<Pin 24<VB | 6 | |
| TXO voltage (Tx mode) | VTXO | 1.8 | 2.3 | 3.2 | Vdc | 6 | |
| Delta TXO voltage (switch from Tx to Rx mode) | VTXO | 100 | mV | 6 | |||
| Transmit attenuator gain | GTX | 4 | 6 | 8 | dB | 1.0kHz | 6 |
| Transmit attenuator range (Tx to Rx mode) | GTX | 40 | 44 | 48 | dB | Tx Mode, Pin 3=250mVrms | 6 |
| Transmit attenuator idle mode gain | GTXI | -16.5 | -13 | -8.5 | dB | Idle Mode, Pin 3=250mVrms | 6 |
| TXO source current (Tx mode) | ISOURCE | 1 | 3 | mA | 6 | ||
| TXO input resistance | RIN | 3.5 | 5 | 8 | kΩ | 6 | |
| Speaker amp gain | GSPK | 33 | 34 | 35 | dB | Pin 19=20mVrms | 6 |
| SKI input resistance | RIN | 15 | 22 | 37 | kΩ | 6 | |
| SKO voltage | VO(SKO) | 2.4 | 3 | 3.6 | Vdc | Pin 19=Cap couple to GND | 6 |
| SKO voltage high | VSKOH | 5.5 | Vdc | Pin 19=0.1V, -100mA Load at Pin 15 | 6 | ||
| SKO voltage low | VSKOL | 600 | mV | Pin 19=0.1V, +100mA Load at Pin 15 | 6 | ||
| Microphone amp gain | GMCI | 32.5 | 34 | 35 | dB | Pin 9=10mVrms, 1KHz | 6 |
| Microphone amp input resistance | RMCI | 6.5 | 10 | 16 | kΩ | 6 | |
| RLO leakage current | ILEAK | 2 | μA | Pin 8=VB+1.0V | 6 | ||
| TLO leakage current | ILEAK | 2 | μA | Pin 6=VB+1.0V | 6 | ||
| Transmit-receive switching threshold | ITH | 0.8 | 1.2 | Ratio of ITLI to IRLI at 20A to switch Tx-Rx comparator | 6 | ||
| CP2 current source | ICP2 | 5 | 10 | 13 | μA | 6 | |
| Distortion Rx mode, RXI to SKO | RXD | 1.5 | % | Pin 27=10mVrms, 1KHz | 6 | ||
| Distortion Tx mode, MCI to TXO | TXD | 2 | % | Pin 9=5mVrms, 1KHz | 6 | ||
| Output resistance (VB) | ROUT | 250 | Ω | IB=1.7mA | 5 | ||
| RXO sink current (Rx mode) | IRXOL | 75 | μA | 6 | |||
| TXO sink current (Tx mode) | ISINK | 75 | μA | 6 | |||
| ACF voltage Rx mode | VACF | 150 | mV | Rx Mode, VCC-Pin 25 voltage | 6 | ||
| ACF voltage Tx mode | VACF | 6 | mV | Tx Mode | 6 | ||
| ACF voltage Idle mode | VACF | 75 | mV | Idle Mode | 6 | ||
| XDC voltage idle mode | VXDC | 0 | Vdc | Idle Mode | 6 | ||
| XDC voltage Tx mode | VXDC | 4 | Vdc | Tx Mode | 6 | ||
| V+ supply current temperature change | -0.2 | %/C | -20 to +60C, V+ 11V, Pin 18=0.7V | 5 | |||
| V+ supply current temperature change | -0.4 | %/C | -20 to +60C, V+ 11V, Pin 18=1.6V | 5 | |||
| VCC voltage temperature change | 0.1 | %/C | -20 to +60C, V+=7.5V | 5 |
CAD (KiCad official)
- Symbol:
MC34018G-S28-R - Footprint:
Package_SO:SOIC-28W_7.5x17.9mm_P1.27mm - 3D model: SOIC-28-300mil (KiCad packages3D, STEP)
- 3D model files:
mc34018g-s28-r-etched.step/mc34018g-s28-r-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);mc34018g-s28-r.step/mc34018g-s28-r.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: UTC(Unisonic Tech) datasheet (8 pp, sha256
55ac3adfb572638e, retrieved 2026-10-22, tier: manufacturer) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).