# CD4541BNSR

**Texas Instruments** · Timers / Clock Oscillators · SOP-14-208mil

CD4541BNSR from Texas Instruments, in a SOP-14-208mil. 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 | RTC | passive | Oscillator timing resistor external connection; resistor value in combination with CTC capacitor sets oscillator frequency per f = 1/(2.3 × RTC × CTC). |
| 2 | CTC | passive | Oscillator timing capacitor external connection; capacitor value in combination with RTC resistor sets oscillator frequency per f = 1/(2.3 × RTC × CTC). |
| 3 | RS | input | External oscillator series resistor terminal or external clock input; can accept external clock signal applied to replace internal oscillator circuit. |
| 4 | NC | unconnected | No connection; internally unconnected pin. |
| 5 | AUTO RESET | input | Automatic power-on reset control input; logic 0 enables automatic reset circuit, logic 1 disables auto reset to reduce power dissipation. |
| 6 | MASTER RESET | input | Manual reset input; positive pulse resets all internal counters and latches and sets output to high state. |
| 7 | VSS | power_in | Ground and negative supply terminal reference. |
| 8 | OUTPUT | output | Timer output terminal; provides Q or Q output from selected counter stage (8th, 10th, 13th, or 16th stage selected by A and B inputs). |
| 9 | Q/Q SELECT | input | Output polarity selection input; determines whether output is normal Q or inverted Q from the selected counter stage. |
| 10 | MODE | input | Mode selection input; logic 1 selects recycle (frequency divider) mode for continuous square wave output, logic 0 selects single-transition timer mode. |
| 11 | NC | unconnected | No connection; internally unconnected pin. |
| 12 | A | input | Frequency selection input A; used with B input to select which counter stage (8th, 10th, 13th, or 16th) provides the output. |
| 13 | B | input | Frequency selection input B; used with A input to select which counter stage (8th, 10th, 13th, or 16th) provides the output. |
| 14 | VDD | power_in | Positive supply voltage terminal; device operates from 3V minimum to 20V maximum rated over -55°C to 125°C temperature range. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOP-14-208mil |
| Category | RTC/Clock Chip |
| Pins | 14 |

## CAD (KiCad official)

- Symbol: `CD4541BNSR`
- Footprint: `Package_SO:SOIC-14_3.9x8.7mm_P1.27mm`
- 3D model: SOP-14-208mil (KiCad packages3D, STEP)
- 3D model files: `cd4541bnsr-etched.step` / `cd4541bnsr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cd4541bnsr.step` / `cd4541bnsr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/cd4541b) (22 pp, sha256 `1c648629cd0ba6ed`, retrieved 2026-10-03, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-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).

[Datasheet PDF](docs/cd4541bnsr-datasheet.pdf)