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Ray ba3121f-e2: specified limits as data (metadata.characteristics, 14 rows from the datasheet) 5ef8b62 1mo ago

BA3121F-E2

ROHM · Audio Power OpAmps · SOP-8

BA3121F-E2 from ROHM, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	OUT1	output	Channel 1 audio output. Drives the power amplifier through a coupling capacitor (typ. 4.7 µF electrolytic). Ground-isolated version of the IN1 signal.
2	VM1	passive	Channel 1 common-mode rejection setting/decoupling node. External capacitor to ground (typ. 22 µF) sets the CMRR performance for amplifier 1-A. Larger capacitance improves low-frequency CMRR.
3	IN1	input	Channel 1 audio input from the source (tape deck / tuner). AC-coupled via an external 4.7 µF capacitor. Typical input resistance 55 kΩ.
4	GND	power_in	Ground reference (car body ground on the source side). All internal circuitry is referenced to this pin.
5	IN2	input	Channel 2 audio input from the source (tape deck / tuner). AC-coupled via an external 4.7 µF capacitor. Typical input resistance 55 kΩ.
6	VM2	passive	Channel 2 common-mode rejection setting/decoupling node, shared with the reference divider. External capacitor to ground (typ. 10 µF) sets CMRR performance for amplifier 2-A.
7	OUT2	output	Channel 2 audio output. Drives the power amplifier through a coupling capacitor (typ. 4.7 µF electrolytic). Ground-isolated version of the IN2 signal.
8	VCC	power_in	Positive power supply. Recommended operating range 4 V to 18 V (typ. 12 V), absolute maximum 18 V. Quiescent current ~9.0 mA typ.

Key specifications

Parameter	Value
Manufacturer	ROHM
Package	SOP-8
Category	Op-amp/Cmp
Pins	8

Ordering variants

BA3121F-E2

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Power Supply Voltage	VCC	4	12	18	V	Ta = 25C	2
Quiescent Current	IQ	5.6	9	14	mA	VIN=0Vrms	2
Output Noise Voltage	VNO		3.5	8	μVrms	BPF=20Hz-20kHz	2
Voltage Gain	GV	-1.5	-0.04	1.5	dB	VOUT=-10dBm, Rg=0Ω	2
Maximum Output Voltage	VOM	1.8	2		Vrms	THD=0.1%, VCC=8V	2
Total Harmonic Distortion	THD		0.002	0.02	%	VOUT=0.7Vrms	2
Common-mode Rejection Ratio	CMRR	41	57		dB		2
Common-mode Voltage	VCM	2.5	3.75		Vrms	VCC=8V, CMRR=40dB	2
Ripple Rejection Ratio	RR	72	80		dB	fRR=100Hz, VRR=-10dBm, Rg=0Ω	2
Input Resistance	RIN	44	55	66	kΩ		2
Power Supply Voltage	VCC			18	V	Ta = 25C	2
Power Dissipation	Pd			0.45	W	Ta = 25C; reduced by 4.5mW in Ta of 1°C over 25°C (Note 1)	2
Operation Temperature	Topr	-30		85	°C		2
Storage Temperature	Tstg	-55		125	°C		2

CAD (KiCad official)

Symbol: BA3121F-E2
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOP-8 (KiCad packages3D, STEP)
3D model files: ba3121f-e2-etched.step / ba3121f-e2-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); ba3121f-e2.step / ba3121f-e2.glb are the bare package body.

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ba3121f-e2.step`	122 KB	You want the bare part, or you mark your own boards.
`ba3121f-e2-etched.step`	1.8 MB	You want the part with `BA3121F-E2` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 474 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: ROHM datasheet (15 pp, sha256 a0c13e55a1f7debc, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF

# BA3121F-E2

**ROHM** · Audio Power OpAmps · SOP-8

BA3121F-E2 from ROHM, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | OUT1 | output | Channel 1 audio output. Drives the power amplifier through a coupling capacitor (typ. 4.7 µF electrolytic). Ground-isolated version of the IN1 signal. |
| 2 | VM1 | passive | Channel 1 common-mode rejection setting/decoupling node. External capacitor to ground (typ. 22 µF) sets the CMRR performance for amplifier 1-A. Larger capacitance improves low-frequency CMRR. |
| 3 | IN1 | input | Channel 1 audio input from the source (tape deck / tuner). AC-coupled via an external 4.7 µF capacitor. Typical input resistance 55 kΩ. |
| 4 | GND | power_in | Ground reference (car body ground on the source side). All internal circuitry is referenced to this pin. |
| 5 | IN2 | input | Channel 2 audio input from the source (tape deck / tuner). AC-coupled via an external 4.7 µF capacitor. Typical input resistance 55 kΩ. |
| 6 | VM2 | passive | Channel 2 common-mode rejection setting/decoupling node, shared with the reference divider. External capacitor to ground (typ. 10 µF) sets CMRR performance for amplifier 2-A. |
| 7 | OUT2 | output | Channel 2 audio output. Drives the power amplifier through a coupling capacitor (typ. 4.7 µF electrolytic). Ground-isolated version of the IN2 signal. |
| 8 | VCC | power_in | Positive power supply. Recommended operating range 4 V to 18 V (typ. 12 V), absolute maximum 18 V. Quiescent current ~9.0 mA typ. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | ROHM |
| Package | SOP-8 |
| Category | Op-amp/Cmp |
| Pins | 8 |

## Ordering variants

- `BA3121F-E2`

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Power Supply Voltage | VCC | 4 | 12 | 18 | V | Ta = 25C | 2 |
| Quiescent Current | IQ | 5.6 | 9 | 14 | mA | VIN=0Vrms | 2 |
| Output Noise Voltage | VNO |  | 3.5 | 8 | μVrms | BPF=20Hz-20kHz | 2 |
| Voltage Gain | GV | -1.5 | -0.04 | 1.5 | dB | VOUT=-10dBm, Rg=0Ω | 2 |
| Maximum Output Voltage | VOM | 1.8 | 2 |  | Vrms | THD=0.1%, VCC=8V | 2 |
| Total Harmonic Distortion | THD |  | 0.002 | 0.02 | % | VOUT=0.7Vrms | 2 |
| Common-mode Rejection Ratio | CMRR | 41 | 57 |  | dB |  | 2 |
| Common-mode Voltage | VCM | 2.5 | 3.75 |  | Vrms | VCC=8V, CMRR=40dB | 2 |
| Ripple Rejection Ratio | RR | 72 | 80 |  | dB | fRR=100Hz, VRR=-10dBm, Rg=0Ω | 2 |
| Input Resistance | RIN | 44 | 55 | 66 | kΩ |  | 2 |
| Power Supply Voltage | VCC |  |  | 18 | V | Ta = 25C | 2 |
| Power Dissipation | Pd |  |  | 0.45 | W | Ta = 25C; reduced by 4.5mW in Ta of 1°C over 25°C (Note 1) | 2 |
| Operation Temperature | Topr | -30 |  | 85 | °C |  | 2 |
| Storage Temperature | Tstg | -55 |  | 125 | °C |  | 2 |

## CAD (KiCad official)

- Symbol: `BA3121F-E2`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `ba3121f-e2-etched.step` / `ba3121f-e2-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ba3121f-e2.step` / `ba3121f-e2.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`ba3121f-e2.step`](ba3121f-e2.step) | 122 KB | You want the bare part, or you mark your own boards. |
| [`ba3121f-e2-etched.step`](ba3121f-e2-etched.step) | 1.8 MB | You want the part with `BA3121F-E2` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 474 faces against 147 in the bare model. It
survives export, section views, and rendering in any CAD tool, and it drops straight
into KiCad or Fusion with no extra setup.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [ROHM datasheet](docs/ba3121f-e2-datasheet.pdf) (15 pp, sha256 `a0c13e55a1f7debc`, retrieved 2026-08-17, tier: manufacturer)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/ba3121f-e2-datasheet.pdf)