TC1232EOA - Processor Supervisor w/ Watchdog | Microchip
MPN: TC1232EOA ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.27 | $1.27 |
| 10 | $1.14 | $11.40 |
| 100 | $0.98 | $98.00 |
| 500 | $0.87 | $435.00 |
| 1,000 | $0.76 | $760.00 |
TC1232EOA Overview
What is a microprocessor supervisor? A microprocessor supervisor (also called a voltage supervisor or reset IC) is a dedicated power management IC that protects a microprocessor or microcontroller from undervoltage, brownout, and code-execution faults. It sits in the power management hierarchy between the DC-DC converter or LDO (which provides the rail) and the MCU itself, forming the third tier of protection after voltage regulation and input protection. Supervisors are essential where deterministic boot behavior and watchdog enforcement are required, distinguishing them from simple comparators or POL converters.
Key features of the TC1232EOA include an adjustable watchdog timebase of 150 ms, 600 ms, or 1200 ms selectable via the TD pin, no requirement for external timing components, and a low quiescent supply current that minimizes battery drain. The PBRST input allows an external push-button or system controller to force a manual reset without an additional debounce circuit. The wide operating supply range of 1.2 V to 5.5 V makes it compatible with both 3.3 V and 5 V microprocessor families.
Technically, the TC1232EOA uses a precision bandgap reference combined with a comparator to detect undervoltage conditions with tight threshold accuracy across the full industrial temperature range. The internal watchdog state machine expects a negative-going edge on the ST input within the selected timeout window; if no edge arrives, /RESET is asserted. The watchdog is fully disabled by tying TD to VCC, simplifying BOM on boards that do not require watchdog supervision.
Typical applications include embedded MCU reset control, industrial PLC and sensor node brownout protection, automotive body controller watchdog supervision, point-of-sale terminal power supervision, and any battery-powered system that requires deterministic start-up after cold-boot or brownout recovery.
Design consideration: choose the watchdog timeout based on the longest legitimate loop iteration in your firmware; setting it too short triggers spurious resets while setting it too long delays fault detection. Place the supervisor close to the MCU reset pin and use a 10 kohm pull-up on the open-drain reset line.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for TC1232EOA — 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:
TC1232COA
✅ Drop-In📋 Reference alternative (not in catalog)
TC1232EPA
✅ Drop-In📋 Reference alternative (not in catalog)
ADM1232ARNZ
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1232ESA
✅ Drop-In📋 Reference alternative (not in catalog)
DS1232LP+
✅ Drop-In📋 Reference alternative (not in catalog)
TC1232EOA Maximum Ratings & Electrical Characteristics
| Function | Microprocessor Supervisor (Reset + Watchdog) |
| Monitored Voltage | 4.5 V to 4.75 V |
| Undervoltage Threshold | 4.5 V (4.25 V, 4.5 V, 4.75 V options in family) |
| Number of Voltages Monitored | 1 |
| Output Type | Open Drain or Open Collector |
| Reset Pulse Width (min) | 250 ms |
| Watchdog Timeout | 150 ms / 600 ms / 1200 ms (selectable) |
| Operating Supply Voltage | 1.2 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial E suffix) |
| External Reset Input (PBRST) | Yes, manual push-button reset |
| Watchdog Input (ST) | Yes, edge-triggered |
| Watchdog Disable | Yes, tie TD to VCC |
| Package | 8-pin SOIC (SO) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (per Microchip SOIC package profile) |
| RoHS Status | Compliant |
| Pbfree / Lead-Free | Yes |
TC1232EOA Pin Configuration
| Pin 1 | /RESET — Active-low reset output (open-drain) |
| Pin 2 | VCC — Supply voltage |
| Pin 3 | GND — Ground |
| Pin 4 | PBRST — Push-button reset input |
| Pin 5 | ST — Watchdog strobe input |
| Pin 6 | TD — Watchdog timebase select |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
Typical Applications
TC1232EOA is suitable for 7 applications: Embedded MCU Reset Supervision, Industrial PLC Brownout Protection, IoT Sensor Node Brownout Recovery, Point-of-Sale Terminal Power Supervision, Automotive Body Controller Watchdog, Battery-Powered Medical Device Supervisor, Datacenter Server BMC Watchdog.
Embedded MCU Reset Supervision
The TC1232EOA supplies a deterministic 250 ms /RESET pulse to an MCU on cold-boot and brownout, preventing code execution from corrupted memory when VCC dips below 4.75 V. Its open-drain /RESET output drives the MCU's reset pin through a 10 kohm pull-up and accepts wired-OR connection with other system reset sources. The 1.2 V to 5.5 V supply range lets it monitor both 3.3 V ARM Cortex-M and 5 V 8051 MCUs from the same footprint. Compared to an internal MCU BOR circuit, the TC1232EOA offers tighter threshold accuracy and a guaranteed minimum reset pulse width, critical for systems requiring UL or IEC 60730 functional safety certification.
Recommended
Industrial PLC Brownout Protection
In a 24 V industrial PLC backplane, the TC1232EOA sits downstream of a 5 V LDO and supervises the MCU rail with a 4.75 V undervoltage threshold, asserting /RESET whenever the rail sags below spec during motor inrush or relay switching. The integrated watchdog timer (selectable 150/600/1200 ms) catches firmware hang-up conditions on the PLC's scan loop, escalating to a clean reset rather than a fault latch. The SO-8 footprint and -40C to +85C rating suit sealed control cabinets, and the wide supply tolerance tolerates the PLC's noisy 5 V backplane without false resets.
Recommended
IoT Sensor Node Brownout Recovery
Battery-powered wireless sensor nodes rely on the TC1232EOA to recover from undervoltage events when a depleted battery's voltage collapses under transmit-current load. Its 4.75 V threshold cleanly detects end-of-discharge on a 4-cell AA battery stack (with LDO regulation), holding the MCU in reset until VCC stabilizes above the threshold for the full 250 ms window. The selectable watchdog timebase lets the firmware team tune the supervisor to the LoRaWAN or Zigbee transmit duty cycle, ensuring spurious resets do not disrupt node commissioning. Quiescent current below 50 microamps preserves battery life during sleep intervals.
Recommended
Point-of-Sale Terminal Power Supervision
POS terminals and payment processors require deterministic reset behavior during hot-swap of battery packs or AC line drops. The TC1232EOA's 4.75 V threshold and 250 ms minimum reset pulse guarantee the secure element and display controller boot from a known state, satisfying PCI PTS smart-card reader stability requirements. Its watchdog timer can be enabled in firmware-debug builds to detect application deadlock during certification, and disabled in shipping firmware. The PBRST pin accepts a front-panel push-button for clean operator-initiated reboot without an external debounce IC.
Recommended
Automotive Body Controller Watchdog
Although not AEC-Q100 qualified in the -E suffix, the TC1232EOA architecture is referenced in non-safety automotive body controllers such as RKE receivers, mirror controllers, and seat-position modules. The watchdog timer enforces a periodic firmware heartbeat, resetting the MCU if the CAN stack task overruns during diagnostic events. The /RESET open-drain output supports parallel connection to an external voltage supervisor for fail-safe redundancy. Industrial temperature rating handles under-dash thermal environments.
Recommended
Battery-Powered Medical Device Supervisor
Portable medical devices such as blood-pressure monitors and glucose meters use the TC1232EOA as the primary brownout detector on a regulated 5 V rail. The precise 4.75 V threshold and 250 ms reset pulse ensure the measurement MCU never executes code with marginal VCC, preventing miscalibrated readings that could affect diagnostic decisions. The push-button reset (PBRST) input provides a clean, debounced manual reset that medical-grade ergonomic buttons require. Pairing the TC1232EOA with a downstream LDO keeps noise-sensitive ADC references isolated from the reset supervisor.
Recommended
Datacenter Server BMC Watchdog
Baseboard management controllers (BMCs) in rack-mount servers use the TC1232EOA equivalent architecture to supervise the host CPU's reset domain, asserting /RESET when the BMC firmware detects a critical thermal or power fault. While the EOA variant targets 5 V rails, its pin-compatibility with lower-threshold family members allows the same PCB footprint to serve 3.3 V and 5 V BMC implementations. The watchdog timer enforces periodic BMC-firmware liveness heartbeats, preventing hung management planes that block remote KVM access during outage response.
Recommended
Recommended Products Summary
Engineering reference data for TC1232EOA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TC1232COA | TC1232EPA | ADM1232ARNZ | MAX1232ESA | DS1232LP+ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Analog Devices | Analog Devices | Analog Devices (Dallas) |
| Package | 8-pin SOIC | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same |
| Reset Threshold | 4.75 V | 4.5 V | 4.25 V | 4.5 V | 4.5 V | 4.5 V |
| Watchdog Timebase | 150/600/1200 ms | 150/600/1200 ms | 150/600/1200 ms | 150/600/1200 ms | 150/600/1200 ms | 150/300/600 ms |
| Reset Output Type | Open Drain | Open Drain | Open Drain | Open Drain | Open Drain | Open Drain |
| Operating Supply Voltage | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 4.5 V to 5.5 V |
| Manual Reset Input (PBRST) | Yes | Yes | Yes | Yes | Yes | Yes |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | 0C to +70C (commercial) |
Key Differentiators
- Highest reset threshold in TC1232 SO-8 family (vs TC1232COA)
- Three-option watchdog timebase selection (vs DS1232LP+)
- Lower unit cost at volume (vs ADM1232ARNZ)
- Industrial temperature range with 5.5 V absolute max (vs DS1232LP+)
Design Notes
Place the TC1232EOA within 25 mm of the MCU's reset pin to minimize the inductance of the /RESET trace - a 10 mm trace at 1 nH/inch can couple switching transients from adjacent DC-DC lines into the reset signal. Use a 10 kohm pull-up resistor on the open-drain /RESET line tied to VCC, not to a separate rail, to avoid phantom reset events during MCU warm-up.
The TC1232EOA's SO-8 package places VCC on pin 2 and GND on pin 3 adjacent to each other, allowing you to place a 100 nF decoupling capacitor on the VCC pin with the GND side sharing the same plane via. The NC pins (7 and 8) should be left floating or tied to GND through a guard ring for improved thermal dissipation in high-noise environments.
Do not connect the PBRST input directly to a mechanical switch without debouncing - even though the TC1232EOA has internal debouncing, long-button-hold events paired with VCC brownout can re-enter reset cycles. Add a 1 kohm series resistor and 100 nF capacitor to ground for robust manual reset, and ensure PBRST is not pulled above VCC + 0.3 V during any transient.
The watchdog ST input expects a clean negative-going edge within the selected timebase window. Asymmetric drive - such as slowly rising edges from an open-drain I/O with weak pull-up - can cause the watchdog to count cycle slips. Drive ST from a strong CMOS output with a 10 kohm pull-up to ensure sub-microsecond fall times.
Compliance Information
RoHS compliant per Microchip product page. E suffix is industrial temperature (-40C to +85C), not automotive grade. For AEC-Q100 qualified supervisors, consult Microchip's automotive-grade portfolio.
