# CH348L

**WCH Jiangsu Qin Heng** · USB Converters · LQFP-100(14x14)

CH348L from WCH Jiangsu Qin Heng, in a LQFP-100(14x14). 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 | DCD5/GPIO40 | bidirectional | UART5 MODEM carrier-detect input, active low, also general-purpose GPIO40; the input is 5V tolerant (FT). |
| 2 | RI5/GPIO41 | bidirectional | UART5 MODEM ring-indicator input, active low, also general-purpose GPIO41; the input is 5V tolerant (FT). |
| 3 | DSR1/GPIO27 | bidirectional | UART1 MODEM data-set-ready input, active low, also general-purpose GPIO27; the input is 5V tolerant (FT). |
| 4 | DCD1/GPIO28 | bidirectional | UART1 MODEM carrier-detect input, active low, also general-purpose GPIO28; the input is 5V tolerant (FT). |
| 5 | RI1/GPIO29 | bidirectional | UART1 MODEM ring-indicator input, active low, also general-purpose GPIO29; the input is 5V tolerant (FT). |
| 6 | NC | unconnected | No-connect pin; must be left floating. |
| 7 | CFG | input | Configuration pin selecting whether all DTRx/TNOWx pins (unified) or individual pins (via pull-down resistors) use the TNOW or DTR function, sampled at power-on. |
| 8 | NC | unconnected | No-connect pin; must be left floating. |
| 9 | NC | unconnected | No-connect pin; must be left floating. |
| 10 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 11 | VCC | power_in | Main 3.3V supply input (3.0V to 3.6V); requires an external decoupling capacitor of about 0.1uF to GND. |
| 12 | XI | input | Crystal oscillator input; an 8MHz crystal with about 22pF load capacitors to GND is required between XI and XO. |
| 13 | XO | output | Crystal oscillator inverting output; connect the 8MHz crystal between XI and XO with about 22pF to GND. |
| 14 | RESET | input | External reset input, active low, with an internal pull-up resistor (RPU about 40K typical). |
| 15 | TXD5 | output | UART5 serial data output, idle high. |
| 16 | RXD5 | input | UART5 serial data input with internal pull-up. |
| 17 | TXD6 | output | UART6 serial data output, idle high. |
| 18 | RXD6 | input | UART6 serial data input with internal pull-up. |
| 19 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 20 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 21 | VIO | power_in | I/O port supply input for the serial and MODEM pins, supporting 1.8V, 2.5V or 3.3V (1.7V to 3.6V); requires an external decoupling capacitor. |
| 22 | VIO | power_in | I/O port supply input for the serial and MODEM pins, supporting 1.8V, 2.5V or 3.3V (1.7V to 3.6V); requires an external decoupling capacitor. |
| 23 | CTS1/GPIO2 | bidirectional | UART1 MODEM clear-to-send input, active low, also general-purpose GPIO2. |
| 24 | RTS1/GPIO3 | bidirectional | UART1 MODEM request-to-send output, active low, also general-purpose GPIO3. |
| 25 | TXD1 | output | UART1 serial data output, idle high. |
| 26 | RXD1 | input | UART1 serial data input with internal pull-up. |
| 27 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 28 | VCC | power_in | Main 3.3V supply input (3.0V to 3.6V); requires an external decoupling capacitor of about 0.1uF to GND. |
| 29 | ACT | output | USB configuration-complete status output, active low. |
| 30 | DTR1/TNOW1/GPIO9 | bidirectional | UART1 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO9, selected by CFG at power-on. |
| 31 | CTS6/GPIO16 | bidirectional | UART6 MODEM clear-to-send input, active low, also general-purpose GPIO16. |
| 32 | RTS6/GPIO17 | bidirectional | UART6 MODEM request-to-send output, active low, also general-purpose GPIO17. |
| 33 | TXD7 | output | UART7 serial data output, idle high. |
| 34 | RXD7 | input | UART7 serial data input with internal pull-up; the input is 5V tolerant (FT). |
| 35 | CTS7/GPIO18 | bidirectional | UART7 MODEM clear-to-send input, active low, also general-purpose GPIO18. |
| 36 | RTS7/GPIO19 | bidirectional | UART7 MODEM request-to-send output, active low, also general-purpose GPIO19. |
| 37 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 38 | DSR7/GPIO45 | bidirectional | UART7 MODEM data-set-ready input, active low, also general-purpose GPIO45; the input is 5V tolerant (FT). |
| 39 | DCD7/GPIO46 | bidirectional | UART7 MODEM carrier-detect input, active low, also general-purpose GPIO46; the input is 5V tolerant (FT). |
| 40 | RI7/GPIO47 | bidirectional | UART7 MODEM ring-indicator input, active low, also general-purpose GPIO47; the input is 5V tolerant (FT). |
| 41 | DSR6/GPIO42 | bidirectional | UART6 MODEM data-set-ready input, active low, also general-purpose GPIO42; the input is 5V tolerant (FT). |
| 42 | DCD6/GPIO43 | bidirectional | UART6 MODEM carrier-detect input, active low, also general-purpose GPIO43; the input is 5V tolerant (FT). |
| 43 | RI6/GPIO44 | bidirectional | UART6 MODEM ring-indicator input, active low, also general-purpose GPIO44; the input is 5V tolerant (FT). |
| 44 | DSR3/GPIO33 | bidirectional | UART3 MODEM data-set-ready input, active low, also general-purpose GPIO33; the input is 5V tolerant (FT). |
| 45 | DCD3/GPIO34 | bidirectional | UART3 MODEM carrier-detect input, active low, also general-purpose GPIO34; the input is 5V tolerant (FT). |
| 46 | RI3/GPIO35 | bidirectional | UART3 MODEM ring-indicator input, active low, also general-purpose GPIO35; the input is 5V tolerant (FT). |
| 47 | TXD2 | output | UART2 serial data output, idle high. |
| 48 | RXD2 | input | UART2 serial data input with internal pull-up; the input is 5V tolerant (FT). |
| 49 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 50 | VIO | power_in | I/O port supply input for the serial and MODEM pins, supporting 1.8V, 2.5V or 3.3V (1.7V to 3.6V); requires an external decoupling capacitor. |
| 51 | CTS3/GPIO6 | bidirectional | UART3 MODEM clear-to-send input, active low, also general-purpose GPIO6; the input is 5V tolerant (FT). |
| 52 | CTS2/GPIO4 | bidirectional | UART2 MODEM clear-to-send input, active low, also general-purpose GPIO4; the input is 5V tolerant (FT). |
| 53 | RTS2/GPIO5 | bidirectional | UART2 MODEM request-to-send output, active low, also general-purpose GPIO5. |
| 54 | RTS3/GPIO7 | bidirectional | UART3 MODEM request-to-send output, active low, also general-purpose GPIO7. |
| 55 | DSR2/GPIO30 | bidirectional | UART2 MODEM data-set-ready input, active low, also general-purpose GPIO30; the input is 5V tolerant (FT). |
| 56 | DCD2/GPIO31 | bidirectional | UART2 MODEM carrier-detect input, active low, also general-purpose GPIO31; the input is 5V tolerant (FT). |
| 57 | RI2/GPIO32 | bidirectional | UART2 MODEM ring-indicator input, active low, also general-purpose GPIO32; the input is 5V tolerant (FT). |
| 58 | NC | unconnected | No-connect pin; must be left floating. |
| 59 | NC | unconnected | No-connect pin; must be left floating. |
| 60 | DSR0/GPIO24 | bidirectional | UART0 MODEM data-set-ready input, active low, also general-purpose GPIO24; the input is 5V tolerant (FT). |
| 61 | DCD0/GPIO26 | bidirectional | UART0 MODEM carrier-detect input, active low, also general-purpose GPIO26; the input is 5V tolerant (FT). |
| 62 | RI0/GPIO25 | bidirectional | UART0 MODEM ring-indicator input, active low, also general-purpose GPIO25; the input is 5V tolerant (FT). |
| 63 | DTR4/TNOW4/GPIO20 | bidirectional | UART4 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO20; the pin is powered from VCC at 3.3V signal level. |
| 64 | DTR5/TNOW5/GPIO21 | bidirectional | UART5 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO21; the pin is powered from VCC at 3.3V signal level. |
| 65 | DTR6/TNOW6/GPIO22 | bidirectional | UART6 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO22; the pin is powered from VCC at 3.3V signal level. |
| 66 | DTR7/TNOW7/GPIO23 | bidirectional | UART7 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO23; the pin is powered from VCC at 3.3V signal level. |
| 67 | DTR2/TNOW2/GPIO10 | bidirectional | UART2 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO10; the input is 5V tolerant (FT). |
| 68 | TXD0 | output | UART0 serial data output, idle high. |
| 69 | RXD0 | input | UART0 serial data input with internal pull-up; the input is 5V tolerant (FT). |
| 70 | CTS0/GPIO0 | bidirectional | UART0 MODEM clear-to-send input, active low, also general-purpose GPIO0; the input is 5V tolerant (FT). |
| 71 | RTS0/GPIO1 | bidirectional | UART0 MODEM request-to-send output, active low, also general-purpose GPIO1; if a pull-down is detected on this pin at power-on, the internal EEPROM configuration is disabled and default parameters are used. |
| 72 | DTR0/TNOW0/GPIO8 | bidirectional | UART0 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO8; the input is 5V tolerant (FT). |
| 73 | NC | unconnected | No-connect pin; must be left floating. |
| 74 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 75 | VCC | power_in | Main 3.3V supply input (3.0V to 3.6V); requires an external decoupling capacitor of about 0.1uF to GND. |
| 76 | TX_S | output | Serial transmit status output; pulses with a 200ms period while any UART is transmitting data. |
| 77 | RX_S | output | Serial receive status output; pulses with a 200ms period while any UART is receiving data. |
| 78 | TXD3 | output | UART3 serial data output, idle high. |
| 79 | RXD3 | input | UART3 serial data input with internal pull-up. |
| 80 | TXD4 | output | UART4 serial data output, idle high. |
| 81 | NC | unconnected | No-connect pin; must be left floating. |
| 82 | NC | unconnected | No-connect pin; must be left floating. |
| 83 | RXD4 | input | UART4 serial data input with internal pull-up; the input is 5V tolerant (FT). |
| 84 | NC | unconnected | No-connect pin; must be left floating. |
| 85 | NC | unconnected | No-connect pin; must be left floating. |
| 86 | DSR4/GPIO36 | bidirectional | UART4 MODEM data-set-ready input, active low, also general-purpose GPIO36; the input is 5V tolerant (FT). |
| 87 | DCD4/GPIO37 | bidirectional | UART4 MODEM carrier-detect input, active low, also general-purpose GPIO37; the input is 5V tolerant (FT). |
| 88 | RI4/GPIO38 | bidirectional | UART4 MODEM ring-indicator input, active low, also general-purpose GPIO38; the input is 5V tolerant (FT). |
| 89 | DTR3/TNOW3/GPIO11 | bidirectional | UART3 MODEM data-terminal-ready output, active low, or RS485 TNOW transmit-status output, also general-purpose GPIO11; the input is 5V tolerant (FT). |
| 90 | CTS4/GPIO12 | bidirectional | UART4 MODEM clear-to-send input, active low, also general-purpose GPIO12; the input is 5V tolerant (FT). |
| 91 | RTS4/GPIO13 | bidirectional | UART4 MODEM request-to-send output, active low, also general-purpose GPIO13. |
| 92 | UD- | bidirectional | USB D- data line, connected directly to the USB bus with no series resistor allowed. |
| 93 | UD+ | bidirectional | USB D+ data line, connected directly to the USB bus with no series resistor allowed. |
| 94 | TEST | input | Internal test pin; connect to ground through a pull-down of about 4.7K or directly to ground. |
| 95 | CTS5/GPIO14 | bidirectional | UART5 MODEM clear-to-send input, active low, also general-purpose GPIO14; the input is 5V tolerant (FT). |
| 96 | RTS5/GPIO15 | bidirectional | UART5 MODEM request-to-send output, active low, also general-purpose GPIO15. |
| 97 | NC | unconnected | No-connect pin; must be left floating. |
| 98 | DSR5/GPIO39 | bidirectional | UART5 MODEM data-set-ready input, active low, also general-purpose GPIO39; the input is 5V tolerant (FT). |
| 99 | GND | power_in | Common ground; must be connected to the USB bus ground. |
| 100 | VIO | power_in | I/O port supply input for the serial and MODEM pins, supporting 1.8V, 2.5V or 3.3V (1.7V to 3.6V); requires an external decoupling capacitor. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | WCH Jiangsu Qin Heng |
| Package | LQFP-100(14x14) |
| Category | Interface |
| Pins | 100 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Operating ambient temperature | TA | -40 |  | 85 | ℃ |  | 7 |
| Storage ambient temperature | TS | -40 |  | 125 | ℃ |  | 7 |
| Power supply voltage (VCC pin, GND grounded) | VCC | -0.3 |  | 4 | V |  | 7 |
| Serial I/O power supply voltage | VIO | -0.3 |  | 4 | V |  | 7 |
| Voltage on USB signal pins | VUSB | -0.5 |  | 3.8 | V |  | 7 |
| Voltage on 5V-tolerant serial pins | VIO5V | -0.5 |  | 5.6 | V |  | 7 |
| Power supply voltage (VCC pin) | VCC | 3 | 3.3 | 3.6 | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Serial I/O power supply voltage | VIO | 1.7 | 3.3 | 3.6 | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Operating supply current, chip normal working | ICC | 28 | 40 | 55 | mA | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Supply current, USB suspend | ISLP | 180 | 260 | 360 | uA | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Low-level input voltage | VIL | 0 |  | 0.8 | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| High-level input voltage | VIH | 2 |  |  | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| High-level input voltage, 5V-tolerant pins | VIH5 | 2 |  | 5 | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Output low voltage | VOL |  |  | 0.4 | V | Single pin sinks 8mA current; TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Built-in pull-up equivalent resistance | RPU | 30 | 40 | 60 | KΩ | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Power-on/power-down reset threshold voltage | VPOR | 1.9 | 2.2 | 2.5 | V | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| ESD withstand voltage (human body model, non-contact) | VESD | 4 |  |  | KV | TA=25℃, VCC=3.3V, excluding USB pins | 8 |
| Reset delay after power-on or external reset input | TRSTD | 15 | 30 | 40 | mS | TA=25℃, VCC=3.3V | 8 |
| USB auto-suspend detection time | TSUSP | 3 | 5 | 9 | mS | TA=25℃, VCC=3.3V | 8 |
| Wake-up completion time after sleep | TWAKE | 0.3 | 0.5 | 4 | mS | TA=25℃, VCC=3.3V | 8 |

## CAD (KiCad official)

- Symbol: `CH348L`
- Footprint: `Package_QFP:LQFP-100_14x14mm_P0.5mm`
- 3D model: LQFP-100(14x14) (KiCad packages3D, STEP)
- 3D model files: `ch348l-etched.step` / `ch348l-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ch348l.step` / `ch348l.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [WCH Jiangsu Qin Heng datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589835198642102272) (9 pp, sha256 `c3adc4a554e74be4`, retrieved 2026-10-18, 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:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (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/ch348l-datasheet.pdf)