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

STMicroelectronics M40Z300WMH6E

Name: M40Z300WMH6E
Brand: STMicroelectronics
SKU: M40Z300WMH6E
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M40Z300WMH6E

Manufacturer:: STMicroelectronics

Category:: Supervisors

Package:: 28-SOIC (0.350", 8.89mm Width) with SNAPHAT Sockets

Datasheet:: M40Z300WMH6E.pdf

Description:: IC SUPERVISOR 1 CHANNEL 28SOH

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Product details

Overview

M40Z300WMH6E from STMicroelectronics is a 3.0 V to 3.6 V non-volatile RAM (NVRAM) supervisor IC that converts low-power SRAMs into battery-backed memory by managing power-fail detection, automatic write-protection, and seamless VCC-to-battery switchover. It supports up to eight SRAMs via dual-device parallel decoding, features open-drain RST and BL outputs, and delivers ≤12 ns chip enable propagation delay at 5.0 V. Used in industrial data loggers for persistent parameter storage during mains loss.

For engineers reviewing the M40Z300WMH6E datasheet, M40Z300WMH6E pinout, M40Z300WMH6E application, or M40Z300WMH6E equivalent, key selection criteria include VPFD threshold select (THS), VSO switchover voltage (2.5 V min), battery low monitoring interval (≥24 h), and SNAPHAT®-compatible 16-pin SOIC packaging with dedicated B+ and B– terminals.

Technical Context

The M40Z300WMH6E integrates a precision voltage reference and comparator to monitor VCC against factory-trimmed VPFD thresholds (2.5 V–2.7 V when THS = VOUT; 2.8 V–3.0 V when THS = VSS). Upon out-of-tolerance detection, it forces E1CON–E4CON inactive within tWPT (≤10 µs) to write-protect attached SRAMs before VCC falls below retention voltage.

It implements a dual-path power switch: during normal operation, VCC feeds VOUT via a <0.3 V drop switch; during power failure, it disconnects VCC and connects the lithium battery (via B+ and B–) to VOUT at VSO (2.5 V typ). The BL pin performs periodic battery voltage checks only under valid VCC, asserting low if VBATT < ~2.5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	2.7 V to 3.6 V - Supports 3.3 V systems with margin for brownout tolerance.
VPFD Threshold	2.5 V–2.7 V (THS = VOUT) or 2.8 V–3.0 V (THS = VSS) - Configurable power-fail detection window for reliable SRAM write-protection timing.
VSO Switchover	2.5 V (typ) - Voltage at which internal switch transfers SRAM supply from VCC to battery, ensuring uninterrupted data retention.
Chip Enable Delay	≤12 ns (at 5.0 V) - Minimal propagation delay from E to E1CON–E4CON preserves SRAM access timing integrity.
BL Monitoring Interval	≥24 hours - Factory-programmed periodic battery health check under nominal VCC, enabling predictive replacement.
RST Pulse Width	tREC = 120 ms (max) - Guaranteed reset hold time after VCC recovery, allowing microprocessor stabilization.
Supply Current	2 mA (typ), 4 mA (max) - Low quiescent draw extends battery life during long-term backup mode.

Pinout & Package

Package: 16-lead SOIC (SO16-MQ), body width 150 mils, RoHS-compliant lead-free finish. Designed for surface-mount assembly with post-reflow SNAPHAT® battery top attachment.

Pin/Terminal	Circuit Role	Design Meaning
1 (A)	Decoder input A	Binary address bit for 2-to-4 decode of E1CON–E4CON; enables control of up to four SRAMs per device.
2 (RST)	Open-drain reset output	Asserts low for ≥120 ms after VCC recovery to ensure microcontroller reset stability; requires external pull-up.
3 (B)	Battery positive connection	Direct anode connection point for external lithium cell; must be wired to B+ terminal of SNAPHAT® housing.
4 (E1CON)	Conditioned chip enable output 1	Active-low output mirroring E input during normal operation; forced high during power fail to write-protect SRAM 1.
5 (E)	Chip enable input	Primary enable signal from host processor; drives all conditioned outputs (E1CON–E4CON) with propagation delay ≤12 ns.
6 (E2CON)	Conditioned chip enable output 2	Second decoded output for independent SRAM control; synchronized with E1CON timing and fail-safe behavior.
7 (B+)	Battery positive terminal	Pin 7 is B+ for M40Z300W - dedicated anode pad for SNAPHAT® battery top; not internally connected to pin 3 (B).
8 (VSS)	Ground	Reference node for all analog comparators and digital logic; must be low-impedance to minimize noise on VPFD sensing.
9 (BL)	Open-drain battery low output	Asserts low when VBATT < ~2.5 V; requires external pull-up to VCC; indicates end-of-life battery requiring replacement.
10 (THS)	Threshold select input	Configures VPFD range: tied to VSS selects 2.8–3.0 V; tied to VOUT selects 2.5–2.7 V - determines switchover sensitivity.
11 (E3CON)	Conditioned chip enable output 3	Third decoded output; enables simultaneous write-protection of third SRAM during power failure events.
12 (E4CON)	Conditioned chip enable output 4	Fourth decoded output; completes 2-to-4 decode set for full four-SRAM control per device.
13 (VOUT)	Regulated output supply	Provides switched VCC or battery voltage to SRAM VCC pin; sourced from internal low-drop switch or B+ during backup.
14 (VCC)	Main supply input	Primary 2.7–3.6 V system rail; powers internal circuitry and feeds VOUT until switchover threshold is reached.
15 (NC)	No connect	Internally unconnected; must remain floating or grounded per layout best practice - no functional role.
16 (B–)	Battery negative terminal	Cathode connection for external lithium cell; must be wired to B– of SNAPHAT® housing - not connected to VSS.

Key Features

Feature	Design Value
Configurable VPFD threshold	Two selectable ranges (2.5–2.7 V or 2.8–3.0 V) via THS pin, enabling precise match to system brownout requirements.
Automatic SRAM write-protection	Forces E1CON–E4CON inactive within ≤10 µs of VPFD violation, preventing corruption during power collapse.
Dual-path power switching	Seamless transition from VCC to battery at VSO (2.5 V typ), maintaining VOUT > 2.0 V to sustain SRAM data retention.
Periodic battery health monitoring	Factory-programmed ≥24-hour BL self-test cycle under valid VCC, enabling predictive maintenance without host intervention.
SNAPHAT®-ready 16-pin SOIC	Dedicated B+ and B– pins (pins 7 and 16) with keyed mechanical interface for post-reflow battery top installation.

Applications

Industrial Data Logger

Medical Device Parameter Storage

Use Scenario: Continuous recording of sensor readings (temperature, pressure) in standalone field instruments with intermittent mains power.

IC Role / Device Role / Timing Role: NVRAM supervisor providing autonomous power-fail detection, SRAM write-protection, and battery-backed retention during grid outages.

Use Value: Guarantees data integrity for >10 years using 120 mAh SNAPHAT® battery and low-I_RET SRAM, eliminating need for EEPROM wear leveling.

Use Scenario: Storing calibration coefficients, usage logs, and fault history in portable diagnostic equipment operating on rechargeable batteries.

IC Role / Device Role / Timing Role: Battery-monitoring supervisor triggering BL alert before critical data loss, while maintaining SRAM contents during deep discharge cycles.

Use Value: Enables scheduled battery replacement based on BL assertion, avoiding unexpected data loss during clinical use.

Programmable Logic Controller (PLC)

Smart Meter Firmware Cache

Use Scenario: Preserving I/O configuration and runtime variables across AC power interruptions in factory-floor PLCs.

IC Role / Device Role / Timing Role: Dual-device parallel decoding (up to 8 SRAMs) provides scalable non-volatile storage for multiple memory banks.

Use Value: Eliminates boot-time reinitialization delays by retaining full context; supports deterministic restart within 120 ms (tREC).

Use Scenario: Caching firmware update payloads and billing registers in utility meters exposed to frequent grid fluctuations.

IC Role / Device Role / Timing Role: Precision VPFD threshold (2.5–2.7 V) aligns with meter MCU brownout detection, ensuring coordinated write-protection.

Use Value: Prevents partial writes during voltage sag, maintaining atomicity of tariff tables and consumption counters.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NVRAM supervisor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6900	Single 3.3 V supply; no THS-selectable VPFD; fixed 2.63 V threshold; no built-in decoder.	Limited to one SRAM; requires external logic for multi-SRAM control; lacks periodic BL monitoring.	Select when only basic power-fail reset and single-memory backup are needed; lower pin count but reduced integration.
DS1230Y	5 V-only operation; integrated lithium battery; no THS pin; fixed 4.75 V VPFD; 28-pin DIP package.	Not suitable for 3.3 V systems; battery soldered-in (no SNAPHAT®); incompatible with surface-mount manufacturing flow.	Choose only for legacy 5 V designs requiring drop-in replacement; unsuitable for new 3.3 V SMT production.

Compared with MAX6900 and DS1230Y, M40Z300WMH6E uniquely combines 3.3 V compatibility, configurable VPFD, 2-to-4 decoding, and SNAPHAT®-enabled post-reflow battery integration - making it the only option supporting scalable, manufacturable, and maintainable NVRAM in modern industrial SMT designs.

Availability

M40Z300WMH6E is available at Aetrix Electronics and suitable for industrial data loggers, medical device parameter storage, and programmable logic controllers requiring stable component supply amid obsolescence transitions.

Supply support for M40Z300WMH6E 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

M40Z300WMH6E belongs to ST's legacy NVRAM supervisor product line, engineered specifically to convert standard LP-SRAMs into robust, battery-backed memory subsystems for mission-critical data retention in harsh power environments.

FAQ

What is the function of the THS pin on M40Z300WMH6E?

The THS (Threshold Select) pin configures the power-fail detection voltage (VPFD) range: when tied to VSS, VPFD is 2.8 V–3.0 V; when tied to VOUT, VPFD is 2.5 V–2.7 V. This allows precise alignment with system brownout thresholds and ensures write-protection triggers before SRAM data retention fails. THS must be hard-wired to either VSS or VOUT - floating is undefined.

Can M40Z300WMH6E support more than four SRAMs?

Yes - two M40Z300WMH6E devices can operate in parallel using shared A/B decoder inputs and separate E1CON–E4CON outputs, enabling control of up to eight SRAMs. Each device independently monitors VCC and asserts its own conditioned outputs, ensuring fail-safe write-protection across all eight memories during a single power event.

How does the BL (Battery Low) pin behave during extended battery backup?

The BL pin performs battery voltage checks only when VCC is present and valid (≥2.7 V); it does not monitor during pure battery backup mode. If BL asserts low, it means VBATT has dropped below ~2.5 V, indicating imminent end-of-life. Data integrity remains intact during backup, but replacement must occur under powered conditions to re-enable monitoring.

Is SNAPHAT® battery top included with M40Z300WMH6E purchase?

No - the SNAPHAT® battery housing (e.g., M4ZXX-BR00SH) is ordered separately. M40Z300WMH6E's 16-pin SOIC includes dedicated B+ and B– pads and mechanical keying for mating with SH-series housings containing 48 mAh or 120 mAh lithium cells. The top is installed post-reflow to avoid thermal damage to the battery.

M40Z300WMH6E Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 28-SOIC (0.350", 8.89mm Width) with SNAPHAT Sockets

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Simple Reset/Power-On Reset

Number of Voltages Monitored:: 1

Voltage - Threshold:: 2.6V

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-SOH

M40Z300WMH6E FAQ

1.How can I place an order for M40Z300WMH6E through Aetrix?

Please submit a Request for Quotation (RFQ) for M40Z300WMH6E 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 M40Z300WMH6E reliable?

The price and inventory of M40Z300WMH6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M40Z300WMH6E is usually 5 days.

3.What payment methods are accepted for M40Z300WMH6E?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M40Z300WMH6E transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M40Z300WMH6E?

M40Z300WMH6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M40Z300WMH6E 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 M40Z300WMH6E?

For technical support, including M40Z300WMH6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M40Z300WMH6E requirements.

6.How does Aetrix verify that M40Z300WMH6E is sourced from the original manufacturer or authorized distributors?

All M40Z300WMH6E 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 M40Z300WMH6E meets industry standards.

7.What is the process for return or replacement of M40Z300WMH6E?

All M40Z300WMH6E units undergo pre-shipment inspection (PSI). If there is an issue with M40Z300WMH6E, 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 M40Z300WMH6E part is unused and in its original packaging.

Return procedure for M40Z300WMH6E:

1.Submit a request within 90 days.

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

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