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STC15W408AS-35I-TSSOP20

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by Ray

STC Micro Microcontrollers (MCU/MPU/SOC), TSSOP-20. Datasheet-verified pinout, KiCad symbol/footprint/3D.

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3D Model

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Symbol & Footprint

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Datasheet

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Contents

README

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STC15W408AS-35I-TSSOP20

STC Micro · Microcontrollers (MCU/MPU/SOC) · TSSOP-20

STC15W408AS-35I-TSSOP20 from STC Micro, in a TSSOP-20. 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 P1.2/ADC2/SS/ECI/CMPO bidirectional Standard I/O PORT1[2]. Muxed with ADC input channel 2, SPI slave-select (SS), CCP/PCA external clock input (ECI), and analog comparator output (CMPO).
2 P1.3/ADC3/MOSI bidirectional Standard I/O PORT1[3]. Muxed with ADC input channel 3 and SPI master-out/slave-in (MOSI).
3 P1.4/ADC4/MISO bidirectional Standard I/O PORT1[4]. Muxed with ADC input channel 4 and SPI master-in/slave-out (MISO).
4 P1.5/ADC5/SCLK bidirectional Standard I/O PORT1[5]. Muxed with ADC input channel 5 and SPI clock (SCLK).
5 P1.6/ADC6/RxD_3/XTAL2/SysClkO_2 bidirectional Standard I/O PORT1[6]. Muxed with ADC input channel 6, alternate UART receive (RxD_3), external-crystal output XTAL2, and secondary system-clock output (SysClkO_2 = SysClk/1, /2, or /4).
6 P1.7/ADC7/TxD_3/XTAL1 bidirectional Standard I/O PORT1[7]. Muxed with ADC input channel 7, alternate UART transmit (TxD_3), and external-crystal input XTAL1 (also external-clock input when a clock source is fed directly).
7 P5.4/RST/SysClkO/CMP- bidirectional Standard I/O PORT5[4]. Muxed with the active-high external reset input (RST), system-clock output (SysClkO = SysClk/1, /2, or /4), and comparator negative input (CMP-, set to high-impedance input when used).
8 VCC power_in Positive supply rail, 2.4 V to 5.5 V.
9 P5.5/CMP+ bidirectional Standard I/O PORT5[5]. Muxed with comparator positive input (CMP+, set to high-impedance input when used).
10 GND power_in Ground / negative supply rail.
11 P3.0/RxD/INT4/T2CLKO bidirectional Standard I/O PORT3[0]. Muxed with UART receive (RxD), external interrupt 4 (INT4, falling-edge only, power-down wake-up capable), and Timer 2 clock output (T2CLKO via INT_CLKO[2]/T2CLKO).
12 P3.1/TxD/T2 bidirectional Standard I/O PORT3[1]. Muxed with UART transmit (TxD) and Timer/Counter 2 external input (T2).
13 P3.2/INT0 bidirectional Standard I/O PORT3[2]. Muxed with external interrupt 0 (INT0). Rising- and falling-edge trigger both supported when IT0=0, falling-edge only when IT0=1. Power-down wake-up capable.
14 P3.3/INT1 bidirectional Standard I/O PORT3[3]. Muxed with external interrupt 1 (INT1). Rising- and falling-edge trigger both supported when IT1=0, falling-edge only when IT1=1. Power-down wake-up capable.
15 P3.4/T0/ECI_2 bidirectional Standard I/O PORT3[4]. Muxed with Timer/Counter 0 external input (T0) and CCP/PCA external pulse input alternate (ECI_2).
16 P3.5/T0CLKO/CCP0_2 bidirectional Standard I/O PORT3[5]. Muxed with Timer 0 clock output (T0CLKO, enabled via INT_CLKO[0]) and CCP0 alternate mapping (CCP0_2, capture/PWM channel 0).
17 P3.6/INT2/RxD_2/CCP1_2 bidirectional Standard I/O PORT3[6]. Muxed with external interrupt 2 (INT2, falling-edge only, power-down wake-up capable), alternate UART receive (RxD_2), and CCP1 alternate mapping (CCP1_2).
18 P3.7/INT3/TxD_2/CCP2/CCP2_2 bidirectional Standard I/O PORT3[7]. Muxed with external interrupt 3 (INT3, falling-edge only, power-down wake-up capable), alternate UART transmit (TxD_2), and CCP2 default/alternate mapping (CCP2 and CCP2_2 capture/PWM channel 2).
19 P1.0/ADC0/CCP1 bidirectional Standard I/O PORT1[0]. Muxed with ADC input channel 0 and CCP1 default mapping (capture/high-speed pulse output/PWM channel 1).
20 P1.1/ADC1/CCP0 bidirectional Standard I/O PORT1[1]. Muxed with ADC input channel 1 and CCP0 default mapping (capture/high-speed pulse output/PWM channel 0).

Key specifications

Parameter Value
Manufacturer STC Micro
Package TSSOP-20
Category MCU
Pins 20

Ordering variants

Same part, different packaging or reel option.

  • STC15W408AS-35I-TSSOP20
  • STC15W408AS-35I-SOP20
  • STC15W408AS-35I-DIP20
  • STC15W408AS-35I-SOP16
  • STC15W408AS-35I-DIP16
  • STC15W408AS-35I-SOP28
  • STC15W408AS-35I-TSSOP28
  • STC15W408AS-35I-SKDIP28
  • STC15W408AS-35I-QFN28

CAD (KiCad official)

  • Symbol: STC15W408AS-35I-TSSOP20
  • Footprint: Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm
  • 3D model: TSSOP-20 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File Size Use it when
stc15w408as-35i-tssop20.step 267 KB You want the bare part, or you mark your own boards.
stc15w408as-35i-tssop20-etched.step 5.0 MB You want the part with STC15W408AS-35I-TSSOP20 already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 1212 faces against 327 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: STC Micro datasheet (1219 pp, sha256 cc8c299c891646e0, retrieved 2026-08-17, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • 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