UM621 series automotive-grade multi-system dual-frequency GNSS combination navigation and positioning module is a high-performance, low-power GNSS module that supports multiple satellite navigation systems such as GPS, Beidou, GLONASS, Galileo and QZSS. The module adopts advanced GNSS chips and algorithms, and has the characteristics of high sensitivity, high precision and strong anti-interference ability. UM621 series modules are widely used in automobiles, autonomous driving, surveying and mapping, navigation, positioning and other fields.
This hardware reference design manual from Unicore Communications covers the UM621 series automotive-grade multi-system dual-frequency GNSS combination navigation and positioning module. Revision R2.0, dated September 2023, expands the document's scope and includes antenna circuit and power supply guidance for hardware designers.
The manual gives reference circuits for active and passive antennas, including 50-ohm RF line matching and LNA placement for passive antennas. It also details the VCC and V_BCKP power requirements, power-up waveform conditions, odometer pulse requirements, and a main component selection table listing a TI RS-232 transceiver and a MAXSCEND LNA. This manual is written in Chinese.
| Main supply voltage VCC | 2.7 V to 3.6 V |
|---|---|
| Backup supply voltage V_BCKP | 1.7 V to 3.6 V |
| RF line impedance | 50 ohm |
| Odometer pulse width | ≥100 μs |
| Odometer pulse frequency | ≤5 kHz |
| VCC power-up start level | Below 0.4 V |
| VCC rise time, 10% to 90% | 100 μs to 10 ms |
| VCC undershoot and ringing | Less than 5% VCC |
| VCC power-up interval after below 0.4 V | Recommended greater than 500 ms |
The module main power VCC operating voltage range is 2.7 V to 3.6 V.
A low-noise amplifier should be added between the passive antenna and the module RF_IN, with 50-ohm impedance matching.
The pulse width must be at least 100 μs and the frequency must be no more than 5 kHz.
An independent power rail is recommended for the antenna feed to reduce the risk of module damage.