TTP224 4-channel touch sensor: specs and pinout
A four-pad capacitive touch module built around the TonTek TTP224 touch pad detector IC. It gives four direct output pins, one per pad.
Specs
| Spec | Value | Source |
|---|---|---|
| Operating voltage | 2.4 V to 5.5 V | source General description and features (p.1) |
| Operating current at VDD 3 V, no load | Low power mode 2.5 uA typ; fast mode 9.0 uA typ | source Features (p.1) |
| Response time at VDD 3 V | TTP224: about 100 ms (fast mode), 200 ms (low power); TTP224N: about 60 ms and 160 ms | source Features (p.1) |
| Touch pads and outputs | 4 touch pads with 4 direct output pins | source General description (p.1) |
| Output options | Direct or toggle mode; CMOS or open drain; active high or active low (pad options TOG, OD, AHLB) | source Features (p.1); option table (p.3) |
| Sensitivity adjustment | External capacitor 0 to 50 pF per pad (smaller value gives higher sensitivity) | source Features (p.1); notes 4 (p.3) |
| Maximum key-on time options | 120 s, 64 s, 16 s or infinite (pads MOT1, MOT0) | source Features (p.1); option table (p.3) |
| Power-on stable time | About 0.5 s; do not touch the pads during this time | source Features (p.1) |
| Auto re-calibration period | About 4.0 s when no key has been touched | source Features (p.1) |
Power
| Value | Source | |
|---|---|---|
| Supply | 2.4-5.5 V (chip) | source Features (p.1) |
| Current | 2.5 uA typ (low power) / 9.0 uA typ (fast mode) at 3 V, no load | source Features (p.1) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
The pin list is for the bare TTP224 IC from the TonTek sheet. The module board's header order, option jumpers and regulator are not covered by an official document.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 3 TP2 | Touch pad input | source Application circuit / option table (pp.2-3) | ||
| 4 TP3 | Touch pad input | Can be disabled by tying DIS13 to VSS. | source Application circuit / option table (pp.2-3) | |
| 5 AHLB | Option pad: output active level (open: active high, VDD: active low) | source Application circuit / option table (pp.2-3) | ||
| 6 VDD | Positive supply | A capacitor C1 between VDD and VSS is required, routed with short tracks. | source Application circuit / option table (pp.2-3) | |
| 7 VREG | Regulator pin | source Application circuit / option table (pp.2-3) | ||
| 8 TOG | Option pad: toggle mode (VDD) or direct mode (open) | source Application circuit / option table (pp.2-3) | ||
| 9 LPMB | Option pad: fast mode (VDD) or low power mode (open) | source Application circuit / option table (pp.2-3) | ||
| 10 MOT1 | Option pad: maximum on time select | source Application circuit / option table (pp.2-3) | ||
| 11 MOT0 | Option pad: maximum on time select | source Application circuit / option table (pp.2-3) | ||
| 12 VSS | Ground | source Application circuit / option table (pp.2-3) | ||
| 13 DIS13 | Option pad: input keys number (VSS disables TP1 and TP3) | source Application circuit / option table (pp.2-3) | ||
| 14 REGEN | Internal regulator enable | source Application circuit / option table (pp.2-3) | ||
| 15 OD | Option pad: open drain (VSS) or CMOS output (open) | source Application circuit / option table (pp.2-3) | ||
| 16 SM | Option pad: single key mode (VSS) or multi-key mode (open) | source Application circuit / option table (pp.2-3) | ||
| 17 TPQ3 | Output for pad 3 | source Application circuit / option table (pp.2-3) | ||
| 18 TPQ2 | Output for pad 2 | source Application circuit / option table (pp.2-3) | ||
| TP0, TP1, TPQ0, TPQ1, TPQ0D, TPQ2D | Touch pad inputs TP0 and TP1; outputs TPQ0 and TPQ1; TPQ0D and TPQ2D are open drain active low outputs without diode protection | Pin numbers for these are not read from the diagram. | source Application circuit / option table (pp.2-3) |
Build with it
Project ideas for the TTP224 4-channel touch sensor. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Four-key touch pad with LEDs: Each pad drives its own output, so the ESP32 can read four inputs and light four LEDs through resistors. Power the module from 3.3 V (chip range 2.4-5.5 V) so its outputs sit at 3.3 V logic; check the output polarity of your module.
- A touch menu with an ESP32, a TTP224 touch sensor module and a 0.96 inch OLED: Use the four pads as up, down, select and back for an OLED menu. Keep your fingers off the pads for the first half second after power-up.
- Four-note touch instrument: Each pad plays one tone on the passive buzzer, which needs a square wave from the ESP32. The chip's 100 ms response time (fast mode) sets how quick the keys feel.
Common mistakes
- Touching the pads at power-up: for about 0.5 s the chip is calibrating and the function is disabled (source: link, Features p.1)
- Expecting a steady output from a held touch: the maximum on time option can switch a held key off after 120 s, 64 s or 16 s (source: link, option table p.3)
- Assuming the output polarity: active high or low and direct or toggle mode are set by option pads, which on a module are board or jumper settings that this sheet does not describe (source: link, option table p.3)
Not covered by the official source
- Chip sheet only; module board option settings, header and regulator are not covered.
- Pin numbers for TP0, TP1 and the TPQ0/TPQ1/TPQ0D/TPQ2D pads were not read from the diagram.
- The sheet is marked Preliminary.
Sources
- link (TonTek TTP224/TTP224N TonTouch 4 key touch pad detector IC datasheet, Preliminary, Ver 2.0, 2009/8/25; copy hosted by Elecrow)