EM6151V55SO8B+ - 5.5V Windowed Watchdog Supervisor | EM Microelectronic
MPN: EM6151V55SO8B+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
EM6151V55SO8B+ Overview
A watchdog supervisor (also called a system supervisor or reset IC) is a dedicated integrated circuit that monitors a microprocessor or microcontroller's activity and forces a reset if the firmware fails to service the watchdog within a defined time window. Watchdog supervisors belong to the broader category of power management ICs, specifically within supervisors and reset circuits. They sit alongside voltage supervisors, battery monitors, and sequencers, providing mission-critical housekeeping functions that software alone cannot guarantee.
Key features include a windowed watchdog timer that detects both premature and missing service pulses, a manual reset input, sleep mode for ultra-low quiescent current, and a single-channel open-drain reset output. The windowed watchdog ensures the host processor services the watchdog within a bounded time interval, catching both stalled code (no service) and runaway code (too-frequent service). The reset output remains asserted for a defined pulse width, allowing the system clock and supply rails to stabilize.
The EM6151 architecture combines a precision voltage reference, a windowed watchdog timer block, and a low-power comparator for VCC monitoring. The 5.5V threshold variant is one of several fixed thresholds offered in the EM6151 family, selected by part number suffix. The device is designed for low quiescent current during sleep mode, enabling battery-powered applications to maintain supervision with minimal drain.
Typical applications include microcontroller reset supervision in industrial controllers, embedded IoT endpoints, automotive body electronics (when paired with an automotive-qualified equivalent), and battery-powered portable instrumentation. The combination of voltage monitoring and windowed watchdog in a single 8-pin SOIC reduces BOM count and PCB footprint.
When designing with this part, ensure the WDI (watchdog input) service pulse timing falls within the watchdog window, and place the decoupling capacitor close to VCC. The sleep mode requires careful sequencing to avoid unintended system lock-up.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, providing engineers with an at-a-glance reference for system supervision design.
Drop-in alternatives for EM6151V55SO8B+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
EM6151V50SO8B+
✅ Drop-In📋 Reference alternative (not in catalog)
EM6151V33SO8B+
✅ Drop-In📋 Reference alternative (not in catalog)
EM6151V30SO8B+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX6754KAUTI+T
✅ Drop-In📋 Reference alternative (not in catalog)
TPS3823-50DBVR
✅ Drop-In📋 Reference alternative (not in catalog)
EM6151V55SO8B+ Specifications
| Function | Windowed Watchdog Supervisor with Reset and Sleep Mode |
| Number of Supervisors | 1 |
| Reset Output Type | Open Drain or Open Collector |
| Watchdog Type | Windowed |
| Voltage Threshold | 5.5 V |
| Manual Reset Input | Yes |
| Sleep Mode | Yes |
| Package | 8-SOIC |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead Free | Yes |
EM6151V55SO8B+ Pin Configuration
| Pin 1 | VCC — Supply voltage input (monitored for brownout) |
| Pin 2 | GND — Ground |
| Pin 3 | RESET — Open-drain reset output |
| Pin 4 | MR — Manual reset input (active low) |
| Pin 5 | WDI — Watchdog input - service pulse from host MCU |
| Pin 6 | SLEEP — Sleep mode control |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
Typical Applications
EM6151V55SO8B+ is suitable for 6 applications: Microcontroller Reset Supervision, Battery-Powered IoT Endpoint, Automotive Body Electronics, Industrial Sensor Hub, Medical Monitoring Device, Point-of-Sale Terminal.
Microcontroller Reset Supervision
The EM6151V55SO8B+ provides hardware reset supervision for 5V microcontrollers in industrial controllers, PLCs, and embedded control boards. The 5.5V threshold matches typical 5V MCU supply rails, triggering RESET when VCC sags during brownout events or power-up. The windowed watchdog catches firmware stalls - if the WDI service pulse is missing or arrives too soon, the EM6151 forces a clean reset and re-initializes the MCU. This dual protection (voltage + firmware) is critical in unattended industrial systems where firmware corruption could cause unsafe actuator states. Recommended companion MPNs: PIC18F46K22, STM32F103.
Recommended
Battery-Powered IoT Endpoint
The EM6151V55SO8B+ enables reliable firmware supervision in battery-powered IoT sensors and remote monitoring nodes. Its sleep mode reduces quiescent current during idle periods, allowing the supervisor to remain active while the host MCU sleeps - the supervisor wakes the host on watchdog timeout to refresh sensor readings. The 5.5V threshold suits 1S Li-ion charger output ranges (3.0V-4.2V) when paired with appropriate voltage scaling, or 5V USB-powered IoT devices. Recommended companion MPNs: ESP32, nRF52840.
Recommended
Automotive Body Electronics
The EM6151V55SO8B+ supports automotive body controllers, instrument cluster MCUs, and HVAC control modules where 5V logic rails are still prevalent. The windowed watchdog detects firmware malfunctions that could leave a body control module in an undefined state (e.g., stuck door lock relay, runaway HVAC actuator). Note that the EM6151V55SO8B+ is industrial-grade; for full AEC-Q100 automotive qualification, verify availability of the EM6151 automotive part variant or substitute an AEC-Q100 device. Recommended companion MPNs: PIC16F1939, S9S12GN48F0CLF.
Recommended
Industrial Sensor Hub
The EM6151V55SO8B+ supervises industrial 4-20mA sensor hubs, RTU (remote terminal unit) controllers, and SCADA node electronics operating from 24V industrial bus rails stepped down to 5V. The windowed watchdog prevents a runaway RTU from flooding the SCADA network with stale or corrupt telemetry - on watchdog timeout, the EM6151 forces a clean restart. The 8-SOIC package fits densely populated sensor hub PCBs where board space is at a premium. Recommended companion MPNs: STM32L073, MSP430FR5969.
Recommended
Medical Monitoring Device
The EM6151V55SO8B+ provides redundant safety supervision in non-life-critical medical monitoring devices such as blood pressure monitors, pulse oximeters, and portable ECG recorders. The windowed watchdog ensures the measurement firmware cannot get stuck in an infinite loop, which would prevent the device from updating its display or alarming the patient. The 5.5V threshold suits mains-powered medical devices with regulated 5V internal rails. For IEC 60601-1 medical certification paths, document the supervisor behavior in the risk management file. Recommended companion MPNs: MSP430F5528, PIC24FJ256GB210.
Recommended
Point-of-Sale Terminal
The EM6151V55SO8B+ supervises POS (point-of-sale) terminals, payment kiosks, and self-checkout electronics where firmware hangs would prevent transaction completion and revenue loss. The windowed watchdog catches both stuck and runaway firmware states, ensuring the terminal can recover from transient software faults without requiring a service technician visit. The 5.5V threshold matches typical 5V logic rails in POS mainboards. The 8-SOIC footprint integrates easily above the main SoC. Recommended companion MPNs: i.MX6ULL, SAMA5D27.
Recommended
Recommended Products Summary
Engineering reference data for EM6151V55SO8B+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | EM6151V50SO8B+ | EM6151V33SO8B+ | EM6151V30SO8B+ | MAX6754KAUTI+T | TPS3823-50DBVR |
|---|---|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | SOT-23-6 | SOT-23-5 |
| Brand | EM Microelectronic | EM Microelectronic | EM Microelectronic | EM Microelectronic | Analog Devices | Texas Instruments |
| Reset Threshold | 5.5 V | 5.0 V | 3.3 V | 3.0 V | 5.0 V | 5.0 V |
| Watchdog Type | Windowed | Windowed | Windowed | Windowed | Windowed | Simple (non-windowed) |
| Reset Output Type | Open Drain | Open Drain | Open Drain | Open Drain | Push-Pull | Push-Pull |
| Manual Reset | Yes | Yes | Yes | Yes | Yes | Yes |
| Sleep Mode | Yes | Yes | Yes | Yes | No | No |
| RoHS Compliant | Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Higher voltage threshold variant of the EM6151 family (vs EM6151V50SO8B+)
- Windowed watchdog architecture (vs TPS3823-50DBVR)
- Sleep mode for ultra-low-power operation (vs MAX6754KAUTI+T)
Design Notes
The WDI (watchdog input) service pulse must arrive within the windowed watchdog's defined timing window - both too-frequent and too-infrequent pulses will trigger a reset. According to the EM6151 datasheet, the window timing is factory-set; consult the datasheet timing diagrams to program your host MCU's WDI toggle rate accordingly. A common pitfall is treating the EM6151 like a simple (non-windowed) watchdog and toggling WDI on every loop iteration - this triggers an immediate reset. Recommended: issue the WDI service pulse only after a defined task completion.
Place a 0.1uF decoupling capacitor as close as possible to the VCC pin (pin 1) of the 8-SOIC package. The EM6151 monitors VCC for brownout events, and any supply noise or ringing on VCC could cause spurious resets. For noisy industrial environments, add a 10uF bulk capacitor in parallel. Keep the RESET trace short and away from switching converter switching nodes to avoid capacitive coupling of noise into the reset line.
Estimated: The EM6151V55SO8B+ typically draws [DATA_NEEDED] uA quiescent current in sleep mode, but verify the exact figure from the manufacturer datasheet before sizing your battery. The open-drain RESET output requires an external pull-up resistor (typically 10k to 100k ohms) tied to the host MCU's logic rail. If the host MCU operates at a lower voltage than the EM6151's VCC, ensure the pull-up is tied to the host's logic rail, not VCC, to prevent damage to the MCU's GPIO pins.
Compliance Information
RoHS and lead-free compliant per '+' suffix designation and DigiKey listing. AEC-Q100 not qualified for the standard variant - consult EM Microelectronic for automotive-grade alternatives. REACH compliance per EU regulatory framework.
