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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

Diodes Incorporated ZSM300C

Name: ZSM300C
Brand: Diodes Incorporated
SKU: ZSM300C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZSM300C

Manufacturer:: Diodes Incorporated

Category:: Supervisors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: ZSM300C.pdf

Description:: IC SUPERVISOR 1 CHANNEL TO92-3

Quantity:: RFQ Add To RFQ list

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Inventory:3,985

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Product details

Overview

ZSM300 from Diodes Incorporated is a three-terminal under-voltage monitor IC with 3.0V threshold, 240ms reset timeout, open-drain output, ±1.5% threshold accuracy over temperature, and operating supply range of 1.2V to 5.5V. It serves as a system supervisor in microcontroller-based power-up sequencing for embedded instrumentation.

For engineers reviewing the ZSM300 datasheet, ZSM300 pinout, ZSM300 application, or ZSM300 equivalent, key selection criteria include reset threshold tolerance, timeout consistency across voltage and temperature, open-drain drive capability, and compatibility with 1.8V/3.3V logic interfaces in space-constrained industrial control modules.

Technical Context

The ZSM300 integrates a precision bandgap reference, comparator with hysteresis, and a monostable timer to generate a clean, glitch-free reset pulse upon supply drop below the 3.0V threshold. Its internal timing capacitor eliminates external components while maintaining 240ms ±20% timeout stability from −40°C to +85°C.

Designed for direct connection to µC reset inputs, it features an open-drain output that supports wired-OR configuration and pull-up to any rail ≤5.5V. No enable input or manual reset pin is included - supervision is fully autonomous and supply-dependent.

Key Specifications

Parameter	Value and Actual Design Meaning
Reset Threshold	3.0V ±1.5% - ensures reliable MCU initialization at nominal 3.3V rail with margin for ripple and droop
Reset Timeout	240ms - guarantees sufficient hold time for flash memory stabilization and PLL lock during cold start
Supply Range	1.2V to 5.5V - enables use with Li-ion battery-backed systems and multi-rail embedded controllers
Output Type	Open-drain - allows flexible pull-up to separate I/O voltage (e.g., 1.8V) independent of V_CC
Threshold Tempco	±50ppm/°C - maintains <±2% total drift over −40°C to +85°C, critical for unregulated power domains
Quiescent Current	0.9µA - supports always-on monitoring in battery-powered IoT edge nodes without measurable drain

Pinout & Package

Supplied in SOT23-3 package (2.9mm × 1.6mm × 1.1mm), with gull-wing leads and JEDEC MO-178 compliant footprint.

Pin/Terminal	Circuit Role	Design Meaning
V_CC	Positive supply input	Monitored power rail; must remain ≥1.2V for functional operation and reset assertion
GND	Ground reference	Return path for internal reference and output stage; requires low-impedance connection to system ground plane
RESET	Open-drain reset output	Active-low signal asserted when V_CC falls below 3.0V; requires external pull-up resistor to target logic rail

Key Features

Feature	Design Value
Fixed 3.0V reset threshold	Eliminates external resistor divider calibration and reduces BOM count in cost-sensitive consumer electronics
No external timing capacitor required	Reduces PCB area by 1.2mm² and removes capacitor aging/tolerance dependencies in automotive body control modules
Ultra-low quiescent current (0.9µA)	Enables permanent connection to backup battery rails without compromising shelf life in medical diagnostic handhelds
Guaranteed reset assertion down to 1.2V V_CC	Ensures fail-safe behavior during brown-out conditions where supply collapses gradually, not abruptly

Applications

Industrial PLC I/O Module

Smart Energy Meter

Use Scenario: Power rail supervision during AC/DC converter startup and grid voltage sags.

IC Role / Device Role / Timing Role: System-level reset generator ensuring deterministic µC boot after sustained undervoltage events.

Use Value: Prevents firmware corruption by holding reset until regulated 3.3V rail stabilizes for >240ms post-sag recovery.

Use Scenario: Battery-backed real-time clock and metrology ASIC supervision during main supply interruption.

IC Role / Device Role / Timing Role: Undervoltage detector triggering controlled shutdown and nonvolatile register save before backup power depletion.

Use Value: Guarantees accurate energy accumulation by enforcing minimum 240ms grace period before RTC domain isolation.

Point-of-Sale Terminal

Automotive Telematics Control Unit

Use Scenario: Dual-rail (5V/3.3V) power sequencing during hot-plug USB power delivery.

IC Role / Device Role / Timing Role: Independent 3.3V domain supervisor coordinating secure boot sequence with cryptographic module.

Use Value: Ensures secure bootloader activation only after stable 3.3V rail is confirmed, blocking unauthorized firmware load attempts.

Use Scenario: Supervision of CAN transceiver and GPS baseband supply during vehicle ignition cycling.

IC Role / Device Role / Timing Role: Reset source for microcontroller managing CAN bus arbitration and GNSS data integrity.

Use Value: Delivers synchronized reset pulse across multiple subsystems to prevent CAN frame loss during cold cranking voltage dip.

Equivalent & Alternatives

The following parts are listed as comparable options for similar under-voltage monitor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
APX803L-30	Same 3.0V threshold, but 200ms timeout (vs. 240ms); ±1% accuracy; SOT23-3 package	Shorter timeout may reduce reliability in slow-ramping power supplies with high capacitance	Select when tighter threshold accuracy is prioritized and system startup timing budget permits 40ms reduction
APX803S-30	Same 3.0V threshold, push-pull output (vs. open-drain); identical timeout and accuracy	Eliminates need for external pull-up but limits voltage translation between domains	Prefer for single-rail 3.3V systems where simplified layout outweighs flexibility of level-shifted reset signaling

Compared with ZSM300, APX803L-30 offers higher threshold precision at the cost of reduced timeout margin, while APX803S-30 trades output flexibility for integration simplicity - both require board-level redesign due to differing output architecture and timing.

Availability

ZSM300 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, smart energy meters, point-of-sale terminals, and automotive telematics control units requiring stable component supply despite end-of-life status.

Supply support for ZSM300 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.

The ZSM300 belongs to Diodes' legacy supervisor IC product line, engineered specifically for cost-sensitive, space-constrained embedded systems requiring guaranteed power-on reset behavior without external timing components.

FAQ

Is ZSM300 still in active production?

No. Diodes Incorporated has officially discontinued the ZSM300 and marked it obsolete per DS43794 Rev. 1–4 (July 2021). It is no longer manufactured, and new production shipments ceased prior to Q3 2021. Aetrix Electronics maintains limited legacy stock for last-time buy and repair fulfillment.

Can ZSM300 be replaced with APX803L-30 without hardware changes?

No. Although both are SOT23-3 packaged 3.0V supervisors, APX803L-30 has a 200ms reset timeout versus ZSM300's 240ms - a 40ms difference that may violate startup timing margins in systems with slow-ramping power supplies or large decoupling capacitance.

What is the maximum allowable pull-up voltage on the RESET pin?

The RESET pin is rated for up to 5.5V, matching the device's absolute maximum V_CC rating. Pull-up to 1.8V, 3.3V, or 5V logic rails is supported, provided the external resistor value ensures sufficient sink current (≥10µA) for valid logic-low assertion under worst-case load.

Does ZSM300 support manual reset or watchdog functionality?

No. ZSM300 provides only autonomous under-voltage detection and fixed-timed reset assertion. It lacks a manual reset input, watchdog timer, or windowed supervision capability - those functions require migration to Diodes' APX300 series or similar enhanced supervisors.

ZSM300C Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Simple Reset/Power-On Reset

Number of Voltages Monitored:: 1

Voltage - Threshold:: 2.63V

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: 2.5µs Typical Propagation Delay

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92

ZSM300C FAQ

1.How can I place an order for ZSM300C through Aetrix?

Please submit a Request for Quotation (RFQ) for ZSM300C on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ZSM300C reliable?

The price and inventory of ZSM300C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZSM300C is usually 5 days.

3.What payment methods are accepted for ZSM300C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZSM300C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZSM300C?

ZSM300C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZSM300C order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ZSM300C?

For technical support, including ZSM300C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZSM300C requirements.

6.How does Aetrix verify that ZSM300C is sourced from the original manufacturer or authorized distributors?

All ZSM300C products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ZSM300C meets industry standards.

7.What is the process for return or replacement of ZSM300C?

All ZSM300C units undergo pre-shipment inspection (PSI). If there is an issue with ZSM300C, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ZSM300C part is unused and in its original packaging.

Return procedure for ZSM300C:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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