WT2003H4-24SS-R Voice Recording Chip
TSSOP24 Voice Chip with 1‑Wire / 2‑Wire Control, 350KB Storage & Built‑in 0.5W Amplifier
The WT2003H4-24SS-R is a TSSOP24 recording and playback voice chip featuring a 32‑bit processor with 350KB of built‑in storage. It supports 1‑wire and 2‑wire serial control for flexible system integration, with 8‑level volume control, a built‑in 0.5W Class‑D amplifier, and support for external SPI‑Flash expansion up to 128Mbit. With deep sleep under 5µA, it is ideal for battery‑powered recording and playback applications.
- 350KB built‑in storage – up to 77s @ 8K recording
- 1‑wire / 2‑wire control – flexible integration
- Built‑in 0.5W amp – 8‑level volume control
- External Flash – up to 128Mbit expansion
- Deep sleep < 5µA – ultra‑low power
Recording Duration Reference
| Chip Type | Storage | Sample Rate | Duration (±30s) |
|---|---|---|---|
| WT2003H4-24SS | Built‑in 350KB | 8K | ~77 seconds |
| 12K | ~51 seconds | ||
| 16K | ~40 seconds | ||
| 24K | ~26 seconds |
Duration is approximate (±30s). Default recording sample rate is 24K. External Flash expansion provides longer durations.
WT2003H4-24SS-R Key Features
Key Commands (1‑Wire / 2‑Wire)
| Command | Function | Description |
|---|---|---|
| F0 | Auto Sleep | Enter sleep after playback ends (5s delay) |
| F1 | Exit Auto Sleep | Stay in standby after playback |
| E0–E7 | Volume Control | E0 = min, E7 = max (8 levels) |
| F2 | Loop Playback | Loop current voice segment |
| F3 + Address | Chain Playback | Play multiple addresses in sequence |
| F5 | Start Recording | Begin recording session |
| F6 | Play Recording | Play back recorded segment |
| F4 00 / F4 01 | Output Mode Switch | F4 00 → DAC, F4 01 → PWM |
| F4 02 / F4 03 | Sleep Mode | Deep sleep / Standby sleep |
| FE | Stop | Stop playback or recording |
| 00H–DFH | Play Address | Play corresponding voice segment (224 addresses) |
Technical Specifications
| Parameter | Value / Condition |
|---|---|
| Package | TSSOP24 |
| Processor | 32‑bit |
| Operating Voltage | 2.4V – 5.2V |
| Built‑in Storage | 350 KB |
| Recording Sampling Rates | 8K, 12K, 16K, 20K, 24K |
| Playback Bitrates | 8 kbps – 320 kbps |
| Audio Output | PWM (0.5W Class‑D) / DAC |
| Volume Levels | 8 (E0–E7) |
| External Flash | Up to 128 Mbit (SPI‑Flash) |
| Control Interfaces | 1‑wire, 2‑wire |
| Busy Indicator | High during recording/playback, low when idle |
| Power‑up Init Time | 200–300 ms |
| Deep Sleep Current | < 5 µA |
| Operating Temperature | ‑40°C ~ +85°C |
Pin Functions (TSSOP24)
| Pin | Name | Function |
|---|---|---|
| 11 | RXD / DATA1 / CLK2 | UART receive / 1‑wire data / 2‑wire clock |
| 12 | LED3 / KEY12 / ADC0 | Multi‑function I/O / MIC input |
| 13 | AGND | Analog ground |
| 14 | LED4 / KEY13 / DAC | DAC output |
| 15 | VOUT | External memory power (1µF cap to ground) |
| 16 | VCC | Power input (2.4–5.2V) |
| 17 | GND | Digital ground |
| 18 | PWM+ | Speaker positive |
| 19 | PWM− | Speaker negative |
| 20 | BUSY | Busy signal output (high during playback/recording) |
| 23 | TXD / DATA2 | UART transmit / 2‑wire data input |
COM and LED pins can be expanded for digital tube and key functions (contact Waytronic for custom firmware).
Application Scenarios
Why Choose WT2003H4-24SS-R
Frequently Asked Questions
What control interfaces does WT2003H4-24SS-R support?
WT2003H4-24SS-R supports 1-wire serial and 2-wire serial control. UART and key control are also available as customizable options.
What is the built-in voice storage capacity?
The WT2003H4-24SS-R provides 350KB of built-in storage, offering approximately 77 seconds at 8K, 51 seconds at 12K, 40 seconds at 16K, and 26 seconds at 24K sampling rates.
Can external Flash be added for extended storage?
Yes. WT2003H4-24SS-R supports external SPI-Flash expansion up to 128Mbit. Waytronic-branded Flash is recommended for guaranteed compatibility.
Does it have a built-in amplifier?
Yes. It features a built-in 0.5W Class-D amplifier with 8-level adjustable volume, capable of directly driving an 8Ω speaker.
What is the default output mode?
By default, PWM output (SPK) is used. DAC output can be enabled by connecting the DAC pin and sending the F4 00 command.
What is the standby current consumption?
The chip enters deep sleep mode after 5 seconds of power-on without playback, with standby current less than 5µA. The first command sent serves as a wake-up trigger.
What is the operating voltage range?
The chip operates from 2.4V to 5.2V, making it compatible with both 3.3V and 5V systems.
What is the power-up initialization time?
The power-on initialization time is 200–300ms. It is recommended to wait 200–300ms before sending control commands.
How do I start and stop recording?
Send the F5 command to start recording and FE to stop recording. The chip records a single segment per session. Use the F6 command to play back the recording.
What are the typical applications?
Voice recorders, interactive toys, security systems, industrial alarms, home appliances, voice prompts, and any application requiring voice recording and playback with low power consumption.
Important: The chip enters deep sleep 5 seconds after power‑on. The first command serves as a wake‑up trigger. For external Flash, Waytronic‑branded Flash is recommended for guaranteed compatibility. The chip is set to PWM output by default – send F4 00 to switch to DAC. The BUSY pin is high during playback/recording and low when idle. Recording circuit uses internal LDO 3.3V – for ultra‑low power (<5µA), alternative power supply through other IO ports is available (custom engineering).
