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Analog Devices Inc./Maxim Integrated DS1236-5
- Part No.:
- DS1236-5
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
DS1236-5.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,944
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Product details
Overview
DS1236-5 from Maxim Integrated is a microprocessor supervisory IC providing precision 5% power supply monitoring (VCCTP = 4.75 V typical), dual active-high/active-low reset outputs, non-maskable interrupt for early power-fail warning, watchdog timer (400 ms typical timeout), and SRAM battery backup control via VCCO switching and CEO write-protection. It serves as a system-level power manager in embedded controllers requiring orderly shutdown and nonvolatile memory retention.
For engineers reviewing the DS1236-5 datasheet, DS1236-5 pinout, DS1236-5 application, or DS1236-5 equivalent, key selection criteria include its 5% VCC trip point accuracy, NMOS/CMOS mode selection via RC pin, dual RST polarity support, battery current < 100 nA at 25°C, and compatibility with 16-pin DIP/SOIC packages for legacy and space-constrained designs.
Technical Context
The DS1236-5 integrates a bandgap voltage reference and precision comparator to monitor +5 V supply (VCC) with a factory-trimmed 5% tolerance threshold (4.75 V typical). Its dual-reset architecture delivers simultaneous active-high and active-low RST signals, synchronized to VCCTP crossing with 40–175 μs propagation delay.
It implements a 400 ms typical watchdog timer triggered by ST input strobing, supports CMOS/NMOS processor modes via RC pin configuration, and provides early-warning NMI generation when IN pin voltage falls below 2.54 V - enabling controlled entry into low-power "stop mode" before full power collapse.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Trip Point | 4.75 V typical (5% option); ensures reset activation before critical microprocessor brownout. |
| Reset Active Time | 25 ms minimum after VCCTP reached; guarantees stable power-up sequencing for 5 V systems. | Watchdog Timeout | 400 ms typical (max 600 ms); prevents runaway code by forcing reset if ST is not strobed. |
| NMI Pulse Width | 200–500 μs; provides deterministic early warning window for software-initiated shutdown. |
| Battery Current | < 100 nA at 25°C; enables multi-year data retention in battery-backed SRAM applications. |
| VCCO Output Capability | 100 mA at VCC−0.3 V; powers external SRAM during main supply operation. |
| IN Trip Voltage | 2.54 V ±0.04 V; sets precise early-warning threshold for user-defined voltage divider networks. |
Pinout & Package
DS1236-5 is available in 16-pin DIP (300-mil) and 16-pin SOIC (300-mil) packages. Both share identical pin mapping and electrical behavior.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VBAT | +3 V battery input | Provides nonvolatile operation of internal logic and VCCO switching during VCC loss. |
| VCCO | Switched SRAM supply output | Delivers higher-of-VCC/VBAT to SRAM; enables seamless battery backup without external diodes. |
| VCC | +5 V primary supply input | Main power source; monitored for out-of-tolerance condition triggering RST/PF/NMI. |
| GND | Ground reference | Common return for all analog and digital circuitry; required for accurate voltage comparison. |
| PF / PF | Power-fail indicators (active high/low) | Drive external MOSFETs or PMICs to switch load between VCC and VBAT during power transitions. |
| WC/SC | Wake-up/Sleep control | Disables comparators and enters ultra-low-power sleep mode; reduces ICC to 20 μA. |
| RC | Reset control input | Selects NMOS (RC=GND) or CMOS (RC=VCCO) timing/level behavior for RST/NMI outputs. |
| IN | Early warning input | User-configurable sense point (via resistor divider) for NMI generation prior to VCCTP crossing. |
| NMI | Non-maskable interrupt output | Pulsed low for ≥200 μs upon IN falling below 2.54 V; signals impending power failure to CPU. |
| ST | Strobe input | Resets watchdog timer on high-to-low transition; must be strobed ≤100 ms to prevent timeout. |
| CEO / CEI | Chip enable output/input | CEO goes high during VCC fail to unconditionally write-protect SRAM; CEI enables normal access. |
| PBRST | Pushbutton reset input | Debounced active-low input; forces 25 ms minimum RST pulse on button release. |
| RST / RST | Reset outputs (active low/high) | Dual-polarity reset signals synchronized to VCCTP; drive microprocessor reset inputs directly. |
Key Features
| Feature | Design Value |
|---|---|
| 5% precision VCC monitoring | Factory-trimmed 4.75 V trip point (4.62 V typical) enables tighter system margin than standard 10% variants. |
| Dual-polarity reset outputs | Simultaneous RST (active low) and RST (active high) eliminate need for external inverters in mixed-logic systems. |
| Configurable processor mode | RC pin selects NMOS (continuous reset hold) or CMOS (NMI-only wake-up) behavior - matching actual processor architecture. |
| Ultra-low battery drain | <100 nA quiescent current preserves coin-cell life for >10 years in nonvolatile SRAM retention. |
| Integrated SRAM power switching | VCCO output automatically selects higher-of-VCC/VBAT, removing need for external OR-ing diodes or ideal diode controllers. |
Applications
| Industrial PLC Controller | Medical Infusion Pump |
|---|---|
Use Scenario: Maintains real-time control logic and calibration data during AC mains interruption or battery swap. IC Role / Device Role / Timing Role: DS1236-5 monitors 5 V rail, asserts RST to halt CPU before brownout, pulses NMI to trigger EEPROM save, and switches SRAM to VBAT via VCCO. Use Value: Prevents data corruption and ensures deterministic restart within 100 ms of power restoration. | Use Scenario: Preserves drug delivery history and safety-critical parameters during brief power dips or battery transition. IC Role / Device Role / Timing Role: DS1236-5 uses IN pin to detect 12 V supply decay at 9.0 V (via R1/R2 divider), issues NMI 200 μs before VCCTP, then holds RST active until VCC stabilizes. Use Value: Guarantees uninterrupted therapy delivery by enabling firmware to complete current dose before entering safe shutdown. |
| Point-of-Sale Terminal | Smart Energy Meter |
Use Scenario: Secures transaction logs and encryption keys during unexpected power loss in retail environments. IC Role / Device Role / Timing Role: DS1236-5 configures RC=VCCO for CMOS mode, uses WC/SC to enter sleep on idle, and wakes on PBRST or ST timeout to resume secure boot. Use Value: Reduces average system current to <50 μA while retaining full cryptographic state across power cycles. | Use Scenario: Retains time-of-use billing data and tamper logs during grid outages lasting hours or days. IC Role / Device Role / Timing Role: DS1236-5 monitors 5 V DC-DC output, drives PF to switch meter MCU and RTC to supercapacitor, and asserts CEO to lock flash writes during VCC collapse. Use Value: Eliminates external power-fail supervisor and SRAM controller ICs - reducing BOM count by 2 components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690T | 5% VCC threshold (4.75 V), but lacks dual RST outputs and NMI; no VCCO switching or CEO write-protection. | Suitable only for basic reset generation - cannot replace DS1236-5 in SRAM backup or early-warning shutdown systems. | Select MAX690T only if application requires only reset assertion and has separate SRAM backup circuitry. |
| TPS3823-50 | Fixed 5.0 V threshold (±1.5%), no NMI, no VCCO output, no CEO, no watchdog; single active-low reset only. | Designed for simple power-on reset in cost-sensitive consumer devices - no nonvolatile memory support. | Choose TPS3823-50 only for new designs where SRAM backup and early warning are unnecessary. |
Compared with MAX690T and TPS3823-50, DS1236-5 uniquely integrates 5% precision monitoring, dual-polarity reset, NMI-based predictive shutdown, and hardware-controlled SRAM write protection - making it irreplaceable in systems requiring guaranteed data integrity during power transients.
Availability
DS1236-5 is available at Aetrix Electronics and suitable for industrial automation, medical device, point-of-sale terminal, and smart meter applications requiring stable component supply and long-term lifecycle support.
Supply support for DS1236-5 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
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The DS1236 product line was designed specifically for microprocessor-based systems needing integrated power supervision, nonvolatile memory backup, and orderly shutdown - targeting legacy and reliability-critical embedded platforms.
FAQ
What is the exact VCC trip point specification for DS1236-5?
The DS1236-5 has a factory-set 5% power supply monitoring threshold with a typical VCCTP of 4.62 V and a guaranteed range of 4.50 V to 4.75 V at 25°C. This tighter tolerance versus the standard 10% DS1236 variant (4.37 V typical) allows earlier, more deterministic reset assertion in systems with narrow 5 V supply margins.
How does DS1236-5 support both NMOS and CMOS microprocessors?
DS1236-5 uses the RC pin to configure operation mode: tied to GND for NMOS systems (continuous RST hold during power loss), or to VCCO for CMOS systems (NMI-only early warning, no forced reset until VCC drops below VBAT). This eliminates external logic and matches actual processor power architecture - ensuring correct reset timing and battery conservation.
Can DS1236-5 directly back up SRAM without external components?
Yes. DS1236-5 provides VCCO output that automatically sources power from the higher of VCC or VBAT, and CEO output that unconditionally disables SRAM writes when VCC falls below VCCTP. Together, they form a complete nonvolatile SRAM subsystem - requiring no external diodes, MOSFETs, or glue logic to retain data during power loss.
What is the role of the IN pin in DS1236-5, and how is it configured?
The IN pin on DS1236-5 is a high-impedance input referenced to a 2.54 V internal threshold. It accepts a user-defined voltage (e.g., from a resistor divider off a 12 V rail) to generate an NMI pulse before VCC reaches VCCTP. Configuration requires selecting R1/R2 values per the equation VSENSE = R2/(R1+R2) × 2.54 V - enabling system-specific early-warning points.
Does DS1236-5 include a watchdog timer, and how is it enabled or disabled?
Yes, DS1236-5 includes a 400 ms typical watchdog timer triggered by ST input strobing. It is enabled by default and resets on each high-to-low ST transition. To disable: ground IN pin in CMOS mode (RC=VCCO), or leave ST open in either mode. Disabling is confirmed by absence of RST assertion after ST inactivity exceeding 600 ms.
DS1236-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- MicroManager
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.62V
- Output:
- Open Drain, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 25ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
DS1236-5 FAQ
1.How can I place an order for DS1236-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1236-5 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 DS1236-5 reliable?
The price and inventory of DS1236-5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1236-5 is usually 5 days.
3.What payment methods are accepted for DS1236-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1236-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1236-5?
DS1236-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1236-5 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 DS1236-5?
For technical support, including DS1236-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1236-5 requirements.
6.How does Aetrix verify that DS1236-5 is sourced from the original manufacturer or authorized distributors?
All DS1236-5 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 DS1236-5 meets industry standards.
7.What is the process for return or replacement of DS1236-5?
All DS1236-5 units undergo pre-shipment inspection (PSI). If there is an issue with DS1236-5, 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 DS1236-5 part is unused and in its original packaging.
Return procedure for DS1236-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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