RT9718 - 30V Overvoltage Protection IC | Richtek
MPN: RT9718 ✓ Hoạt độngRT9718 Tóm tắt
An overvoltage protection IC is a battery management semiconductor that disconnects the load or charging path when the input or battery voltage exceeds a preset safe threshold, preventing damage to downstream components and the cell itself. Overvoltage protection ICs sit beneath supervisors and reset ICs in the power management hierarchy, and above discrete Zener-diode clamping solutions, delivering higher accuracy and programmable thresholds.
Key specifications of the RT9718 include a wide input voltage range up to 30V maximum, internal overvoltage threshold detection, low quiescent current consumption, and integrated MOSFET control for high-side switching. The IC operates from typical 1-cell Li-ion/Li-poly battery voltages (nominally 3.0V to 4.4V) while tolerating abnormal charger insertion up to 30V without damage.
The RT9718 uses a precision bandgap reference and comparator architecture to detect overvoltage conditions with millivolt-level accuracy. According to the manufacturer datasheet DS9718-05, the device latches off the internal pass element when the input voltage exceeds the programmed threshold, protecting downstream USB controllers, PMICs, and battery cells. The integrated current-sense path also monitors charging current against an externally programmable limit.
Typical applications include single-cell Li-ion battery packs, USB charger front-end protection, mobile phone power-path management, handheld portable devices, and any 1S battery-powered system exposed to faulty or non-compliant adapters. The device is widely used as a discrete replacement for protection FETs combined with a separate supervisor IC.
When designing with the RT9718, observe the absolute maximum input voltage of 30V and select external sense resistors to set the desired overvoltage and overcurrent trip thresholds. Place input decoupling capacitors as close to the IN pin as possible to suppress transient events.
This page synthesizes distributor pricing, drop-in package-compatible alternatives, application circuit guidance, and detailed design notes that complement the Richtek datasheet for engineers evaluating the RT9718 for new designs or as a second-source part.
Bộ thay thế dễ dàng lắp đặt cho RT9718 — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
RT9715BGQW
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
RT9712BGQW
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
RT9742CGQW
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
RT9748CGQW
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
RT8971CGQW
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
RT9718 Thông số kỹ thuật
| Product Type | Overvoltage Protection IC |
| Chức năng | Battery / Input Overvoltage Protection with Charging Current Monitor |
| Phạm vi điện áp đầu vào | Up to 30V (abnormal transient) |
| Normal Operating Battery Voltage | 1-cell Li-ion / Li-poly (3.0 V to 4.4 V nominal) |
| Maximum Continuous Input Voltage | 30 V |
| Monitored Parameters | Input voltage, battery voltage, charging current |
| Hộp | 8-WDFN (2x2 mm), suffix BGQW / CGQW |
| Kiểu lắp đặt | Surface Mount |
| Charging Current Sense | External sense resistor programmable |
| Internal MOSFET | Integrated high-side switch |
| Compliance | RoHS compliant (per Richtek product page) |
| Manufacturer Document | DS9718-05 |
Cấu hình chân RT9718
| Chân 1 | IN — Input voltage / charger VBUS sense |
| Chân 2 | IN — Input voltage (continued) |
| Chân 3 | CS — Current sense (to external sense resistor) |
| Chân 4 | GND — Ground reference |
| Chân 5 | BAT — Battery voltage monitor |
| Chân 6 | OUT — Switched output to system load |
| Chân 7 | OUT — Switched output (continued) |
| Chân 8 | EP — Exposed pad (thermal / ground) |
Ứng dụng tiêu biểu
RT9718 phù hợp cho 6 Áp dụngs: 1-Cell Li-ion Battery Pack Protection, USB Type-C / PD Charger Front-End Protection, Mobile Phone and Smartphone Power Path, Handheld Portable Devices and Wearables, USB Power Bank and Power Stick Designs, Industrial Handheld Scanner and POS Terminals.
1-Cell Li-ion Battery Pack Protection
The RT9718 provides primary overvoltage, undervoltage, and overcurrent protection for single-cell Li-ion/Li-poly battery packs, with 30V input tolerance absorbing faulty charger transients that would otherwise damage the cell. Its integrated high-side MOSFET replaces discrete protection FETs, cutting BOM count by 3-4 parts. According to Richtek datasheet DS9718-05, the device's battery voltage monitor prevents overcharge above 4.4V, extending cell cycle life and preventing thermal runaway in consumer battery packs.
Được đề xuất
USB Type-C / PD Charger Front-End Protection
In USB Type-C and Power Delivery systems, the RT9718 sits between the VBUS input and the system PMIC to disconnect the rail when a misconfigured PD adapter injects 12V or 20V into a 5V-only subsystem. Its 30V absolute maximum withstands USB-PD's highest 20V profile plus inductive ringing. Per Richtek datasheet DS9718-05, the integrated OVP comparator trips within microseconds, faster than typical software-based protection, shielding downstream PMICs, chargers, and battery cells from overvoltage events.
Được đề xuất
Mobile Phone and Smartphone Power Path
Smartphones use the RT9718 as the overvoltage gate at the charging port, ensuring that a defective wall adapter cannot push unsafe voltages into the phone's charging IC and battery. The WDFN-8 (2x2 mm) footprint fits easily on the already-crowded main board near the USB connector. With a programmable OCP threshold via external sense resistor, designers tune the protection level to match the phone's fast-charging current envelope without nuisance tripping.
Được đề xuất
Handheld Portable Devices and Wearables
Wearable devices and handheld electronics benefit from the RT9718's tiny 2x2 mm WDFN-8 footprint and integrated protection, eliminating the discrete FET-plus-supervisor solution that would not fit on a small flex PCB. The device's low quiescent current minimizes parasitic drain on the small wearable battery, extending standby time. Designers place the RT9718 directly at the charging input, providing the first line of defense before the main PMIC.
Được đề xuất
USB Power Bank and Power Stick Designs
Power banks and USB power sticks use the RT9718 to safeguard the 1S Li-ion cell from charger-induced overvoltage and to provide load-side overcurrent protection during discharge. The integrated current sense eliminates the need for an external current-sense amplifier, reducing PCB area and BOM cost. Per Richtek datasheet DS9718-05, the device's latch-off behavior after an OVP event ensures the fault is not cleared until the user power-cycles the device, satisfying USB battery pack safety certifications.
Được đề xuất
Industrial Handheld Scanner and POS Terminals
Industrial handheld scanners and point-of-sale terminals deployed in field environments are exposed to unpredictable charger quality and ESD events, making the RT9718's 30V input tolerance critical for long-term reliability. The device prevents system damage when maintenance staff plug in a non-standard 12V or 24V power supply. Its integrated OVP+OCP+Battery monitor function replaces multiple discrete protection components, simplifying the ruggedized enclosure's internal cabling and connectors.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho RT9718 — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | RT9715BGQW | RT9712BGQW | RT9742CGQW |
|---|---|---|---|---|
| Brand | Richtek Technology | Richtek Technology | Richtek Technology | Richtek Technology |
| Package | WDFN-8 (2x2 mm) | WDFN-8 (2x2 mm) - same | WDFN-8 (2x2 mm) - same | WDFN-8 (2x2 mm) - same |
| Maximum Input Voltage | 30 V | ~6 V | ~6 V | 30 V |
| Battery Chemistry | 1S Li-ion / Li-poly | 1S Li-ion / Li-poly | 1S Li-ion / Li-poly | USB load / no battery monitor |
| OVP Function | Yes (integrated) | Yes | Yes | Yes (load switch with OVP) |
| OCP Function | Yes (external sense) | Yes | Yes | Yes |
| Battery Voltage Monitor | Yes | Yes | Yes | No |
Bảo phân biệt quan trọng
- 30V input tolerance for USB-PD and faulty-adapter protection (vsRT9715BGQW)
- Integrated 1S battery voltage monitor in same package (vsRT9742CGQW)
- WDFN-8 (2x2 mm) footprint shared with multiple Richtek OVP ICs (vsDiscrete protection FET + supervisor solution)
Ghi chú thiết kế
Estimated: at a continuous load current of 1.5A and a 5V input, the RT9718's internal high-side MOSFET dissipates approximately P = I^2 x Rds(on). With Rds(on) in the 50-100 mΩ range, dissipation is 0.11W to 0.23W, well within the WDFN-8's thermal capability. The exposed pad must be soldered to a sufficient copper pour (at least 10 mm^2) to maintain the rated SOA. For continuous loads above 2A, verify junction temperature rise against the layout's thermal resistance.
Place input decoupling (1 µF X7R ceramic minimum) directly at the IN pin and the BAT pin to suppress transient voltage spikes that could cause false OVP triggering. Route the sense resistor traces as a Kelvin connection to the CS pin to avoid ground-loop errors in the overcurrent measurement. The exposed pad on the WDFN-8 package should be soldered to a continuous ground plane for both thermal dissipation and low-impedance grounding.
Do not operate the RT9718 above 30V on the IN pin - even though the absolute maximum rating is 30V, transients above this will permanently damage the device. When the OVP trips, the part latches off; the system must power-cycle IN to recover, which is intentional but can surprise engineers expecting auto-retry. Select the external sense resistor with a 1% tolerance and adequate power rating (typically 250 mW minimum for portable applications) to ensure OCP threshold accuracy.
Keep the high-current path (IN to OUT through the internal MOSFET) short and wide to minimize parasitic inductance that could cause voltage ringing during load transients. Per Richtek datasheet DS9718-05, the GND pin and exposed pad should tie directly to the system ground plane with multiple vias for thermal relief. Avoid routing sensitive analog signals (such as audio or RF) directly under the WDFN-8 package, as the switching node can inject noise into nearby traces.
Thông tin tuân thủ
RoHS and lead-free status confirmed via Richtek product page. REACH, halogen-free, and conflict-minerals declarations should be confirmed by requesting the latest Richtek material declaration sheet for the RT9718 part family.
