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Analog Devices Inc./Maxim Integrated MAX692ACSA+
- Part No.:
- MAX692ACSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX692ACSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,360
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Product details
Overview
The MAX692ACSA+ from Maxim Integrated is a microprocessor supervisory circuit providing precision reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts active-low RESET during power-up (VCC ≥ 1V), brownout (VCC < 4.40V), and watchdog timeout (1.6s), while delivering VOUT from VCC or VBATT with 5Ω/80Ω PMOS switching and consuming only 200μA quiescent current. It is used in battery-powered controllers requiring reliable μP initialization and RAM retention during supply interruption.
For engineers reviewing the MAX692ACSA+ datasheet, MAX692ACSA+ pinout, MAX692ACSA+ application, or MAX692ACSA+ equivalent, key selection criteria include its 4.40V reset threshold, 200ms reset pulse width, guaranteed RESET assertion down to VCC = 1V, battery-switching hysteresis of 40mV, and compatibility with lithium backup batteries up to 4.55V.
Technical Context
The MAX692ACSA+ integrates four independent functional blocks: a precision voltage monitor with 4.40V ±2% reset threshold, a 1.6s watchdog timer cleared by WDI edges or RESET assertion, a power-fail comparator referenced to 1.25V with 400ns response time, and a dual-path battery switchover circuit that connects VOUT to VCC (5Ω) above threshold or VBATT (80Ω) below threshold with 20mV switchover hysteresis.
Its RESET output remains low for 200ms after VCC rises above 4.40V and stays asserted as long as VCC remains below 1V; the PFO output goes low when PFI falls below 1.25V; and the WDI input accepts 50ns pulses with internal 35% VCC bias and 50kΩ impedance - all operating across 0°C to +70°C in 8-pin SO package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±2% - triggers RESET when VCC drops below this level; optimized for +5V ±10% supplies. |
| Reset Pulse Width | 200ms - ensures μP completes full reset sequence before releasing control; minimum 140ms guaranteed. |
| Watchdog Timeout | 1.6s - detects software lockup; timer clears on WDI edge, RESET assertion, or WDI high-impedance state. |
| Quiescent Current | 200μA - enables long-term operation from primary supply without excessive loading. |
| Battery-Backup Current | 50nA - draws negligible current from VBATT when VCC is valid, preserving battery life. |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path) - limits voltage drop under load; supports ≤50mA VOUT sourcing. |
| Power-Fail Comparator Threshold | 1.25V - fixed internal reference for PFI; enables accurate undervoltage warning for non-5V rails. |
Pinout & Package
MAX692ACSA+ is housed in an 8-pin SO (Small Outline) package with gull-wing leads, JEDEC MS-012AC compliant, 3.9mm body width, 1.75mm height, and 1.27mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (5Ω) and VBATT (80Ω); maintains RAM power during brownout. |
| 2 - VCC | +5V main supply input | Primary power source; monitored for reset generation and switchover control. |
| 3 - GND | Circuit ground reference | Common return for all analog and digital functions; must be low-impedance. |
| 4 - PFI | Power-fail comparator input | Compares external voltage to 1.25V reference; drives PFO low when input < 1.25V. |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating supply degradation; requires external pull-up. |
| 6 - WDI | Watchdog timer input | Edge-sensitive; floating or high-Z disables watchdog; 50ns minimum pulse width accepted. |
| 7 - RESET | Active-low reset output | Push-pull output; guaranteed low down to VCC = 1V; 200ms pulse on all reset events. |
| 8 - VBATT | Backup battery input | Accepts 2.8V–4.55V lithium cells; enables switchover only when VCC < reset threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | 4.40V ±2% - eliminates need for external resistor divider; supports tight tolerance +5V systems. |
| Guaranteed RESET at low VCC | Asserts logic-low RESET down to VCC = 1V - ensures μP remains held in reset during deep brownout. |
| Low-power battery mode | 50nA quiescent current when VCC = 0V and VBATT = 2.8V - extends lithium battery life to >10 years. |
| Fast power-fail response | 400ns propagation delay from PFI transition to PFO output - enables timely system shutdown. |
| Controlled switchover hysteresis | 40mV hysteresis prevents oscillation during slow VCC decay - avoids repeated RAM supply toggling. |
Applications
| Battery-Powered Controllers | Intelligent Instruments |
|---|---|
Use Scenario: Portable data loggers powered by coin-cell batteries require uninterrupted RAM retention during AC power loss or battery swap. IC Role / Device Role / Timing Role: MAX692ACSA+ monitors VCC, switches VOUT to VBATT within microseconds upon brownout, and holds μP in RESET until stable supply returns. Use Value: Prevents RAM corruption and firmware crash; enables hot-swap capability without system reset. |
Use Scenario: Handheld multimeters with real-time clock and calibration memory must retain settings during brief battery replacement. IC Role / Device Role / Timing Role: MAX692ACSA+ provides 200ms RESET pulse on power-up and guarantees VOUT continuity from VBATT during VCC interruption. Use Value: Eliminates need for supercapacitors or complex backup regulators; reduces BOM count by 3+ components. |
| Critical μP Power Monitoring | Industrial Remote Sensors |
Use Scenario: PLC I/O modules deployed in factory environments experience voltage sags due to motor startup transients. IC Role / Device Role / Timing Role: MAX692ACSA+ detects 4.40V brownout, asserts RESET for 200ms, and disables peripheral clocks via PFO interrupt before supply collapse. Use Value: Avoids spurious I/O writes and communication errors; meets IEC 61000-4-11 immunity requirements. |
Use Scenario: Wireless sensor nodes in oil-field telemetry operate on primary Li-SOCl₂ batteries with 10-year lifetime expectations. IC Role / Device Role / Timing Role: MAX692ACSA+ uses 50nA battery mode and 4.55V max VBATT rating to maximize energy efficiency and prevent overvoltage damage. Use Value: Extends field deployment interval; eliminates premature battery drain from supervisory leakage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802MCSA | Identical reset threshold (4.40V), same 200ms reset width, but specified for 0°C to +70°C with ±2% power-fail accuracy guarantee. | Designed for cost-sensitive industrial controls where PFI accuracy is critical for predictive shutdown. | Select MAX802MCSA if ±2% PFI accuracy is required; MAX692ACSA+ offers identical core functionality with broader legacy support. |
| MAX706RCSA+ | Lower reset threshold (2.93V), no battery switchover, no PFI/PFO, but adds manual reset input and watchdog output. | Suitable for 3.3V systems or designs needing external reset button integration without backup power. | Choose MAX706RCSA+ only for 3.3V μP systems without battery backup; MAX692ACSA+ is not functionally substitutable due to missing manual reset and different voltage domain. |
Compared with MAX802MCSA and MAX706RCSA+, the MAX692ACSA+ uniquely combines 4.40V reset, battery switchover, and PFI/PFO in one 8-pin SO device - making it irreplaceable in +5V battery-backed μP applications requiring all three functions.
Availability
MAX692ACSA+ is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, and critical μP power monitoring requiring stable component supply across industrial temperature ranges and long-lifecycle programs.
Supply support for MAX692ACSA+ 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 high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MAX692ACSA+ belongs to Maxim's microprocessor supervisory product line, designed specifically to replace discrete reset generators and backup power circuits in +5V μP systems with integrated, pin-compatible reliability.
FAQ
What is the guaranteed minimum VCC level at which MAX692ACSA+ asserts RESET?
The MAX692ACSA+ guarantees RESET assertion down to VCC = 1V. This ensures the microprocessor remains held in reset even during severe brownout conditions where supply voltage collapses below typical logic thresholds. The device continues asserting RESET until VCC rises above 4.40V and sustains the 200ms reset pulse width - a critical feature for preventing erratic μP behavior in unstable power environments. This specification is explicitly tested and guaranteed across the full 0°C to +70°C operating range for MAX692ACSA+.
Does MAX692ACSA+ support lithium backup batteries, and what is the maximum allowable VBATT voltage?
Yes, MAX692ACSA+ supports lithium backup batteries with an open-circuit voltage up to 4.55V - as confirmed in Table 2 of the datasheet. This limit prevents substrate diode conduction when VCC approaches the 4.40V reset threshold. The device draws only 50nA from VBATT in backup mode, enabling multi-year operation from standard CR2032 or BR2032 cells. Operation above 4.55V risks uncontrolled current flow into the substrate, potentially damaging the IC or depleting the battery prematurely.
How does the watchdog timer in MAX692ACSA+ behave when WDI is left unconnected?
When WDI is left floating or connected to a high-impedance (three-state) buffer, the internal watchdog timer in MAX692ACSA+ is disabled - as stated in the Pin Description section. The WDI pin has an internal 35% VCC bias and 50kΩ input impedance, placing it in a non-logic state that prevents timeout triggering. This behavior allows safe omission of watchdog servicing in applications where software supervision is unnecessary, without requiring external pull-up/down resistors. The timer only activates when WDI is actively driven high or low for >1.6s.
Can MAX692ACSA+ monitor a negative supply rail, and how is this implemented?
Yes, MAX692ACSA+ can monitor a negative supply rail using the PFI input and an external resistor network as shown in Figure 7 of the datasheet. A voltage divider referenced to ground converts the negative rail magnitude into a positive voltage applied to PFI. When the negative rail degrades (e.g., becomes less negative), the PFI voltage rises above 1.25V, causing PFO to go high - signaling supply failure. Accuracy depends on resistor tolerance and PFI input current (≤25nA), so 1% resistors are recommended. This technique enables single-supply monitoring of dual-rail systems without additional comparators.
What is the purpose of the 40mV hysteresis in the battery switchover circuit of MAX692ACSA+?
The 40mV hysteresis in the MAX692ACSA+ battery switchover circuit prevents rapid toggling of VOUT between VCC and VBATT when VCC decays slowly near the 4.40V reset threshold. Without hysteresis, small noise or ripple could cause repeated switching - inducing voltage glitches on RAM supply and increasing wear on the internal 80Ω PMOS switch. The hysteresis ensures VBATT engages only when VCC falls 20mV below threshold and disengages only when VCC rises 20mV above threshold, providing clean, glitch-free power transfer essential for data integrity in battery-backed memory systems.
MAX692ACSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.4V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX692ACSA+ FAQ
1.How can I place an order for MAX692ACSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX692ACSA+ 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 MAX692ACSA+ reliable?
The price and inventory of MAX692ACSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX692ACSA+ is usually 5 days.
3.What payment methods are accepted for MAX692ACSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX692ACSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX692ACSA+?
MAX692ACSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX692ACSA+ 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 MAX692ACSA+?
For technical support, including MAX692ACSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX692ACSA+ requirements.
6.How does Aetrix verify that MAX692ACSA+ is sourced from the original manufacturer or authorized distributors?
All MAX692ACSA+ 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 MAX692ACSA+ meets industry standards.
7.What is the process for return or replacement of MAX692ACSA+?
All MAX692ACSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX692ACSA+, 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 MAX692ACSA+ part is unused and in its original packaging.
Return procedure for MAX692ACSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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