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Analog Devices Inc./Maxim Integrated MAX690TCSA+T
- Part No.:
- MAX690TCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690TCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,778
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Product details
Overview
MAX690TCSA+T from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-low RESET output, 3.075V reset threshold, 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover-designed for reliable power monitoring in battery-powered embedded controllers and portable instrumentation.
For engineers reviewing the MAX690TCSA+T datasheet, MAX690TCSA+T pinout, MAX690TCSA+T application, or MAX690TCSA+T equivalent, this page delivers verified specifications, validated pin functions, confirmed use cases in brownout-critical systems, and two technically documented alternative parts for 3.0V/3.3V µP supervision.
Technical Context
The MAX690TCSA+T integrates a precision voltage monitor, reset generator with hysteresis, 1.6s watchdog timer, and bidirectional battery switchover circuitry-enabling seamless RAM backup during VCC brownouts. Its reset comparator guarantees assertion down to VCC = 1V, and the PFI/PFO pair provides independent power-fail detection at 1.237V with ±10mV hysteresis.
It operates across 0°C to +70°C, supports VCC from 3.17V to 5.5V (for T-suffix), draws only 40µA supply current at VCC < 3.6V, and features a 3Ω VCC-to-VOUT PMOS switch plus 140Ω VBATT-to-VOUT switch-ensuring low-dropout CMOS RAM retention during switchover.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (VCC falling), ±75mV tolerance - ensures reset asserts before 3.3V supply drops below system stability margin. |
| Reset Timeout Period | 200ms (typical) - guarantees µP remains held in reset long enough for stable power recovery and clock stabilization. |
| Watchdog Timeout | 1.6s - detects µP lockup without requiring software intervention; cleared on WDI edge transitions. |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables multi-year operation in battery-backed applications like portable data loggers. |
| Battery Supply Current | 0.4–1µA (max) - minimizes drain on lithium coin cells during extended backup mode. |
| VBATT Switch Threshold | VSW = 2.40V (typ) - triggers switchover prior to CMOS RAM's 2.0V data-retention limit, preserving memory integrity. |
| Power-Fail Threshold | 1.237V at PFI input - allows external resistor divider to monitor auxiliary supplies (e.g., 5V rail) with noise-immune detection. |
Pinout & Package
MAX690TCSA+T is housed in an 8-pin SOIC package (SO, 150mil width), RoHS-compliant (indicated by '+' suffix), with standard 1.27mm pitch and gull-wing leads suitable for automated PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT via internal MOSFETs; connects to RAM VDD to maintain data during brownout. |
| 2 - VCC | Main system supply input | Primary 3.0V/3.3V power source; powers internal circuitry and defines reset threshold reference. |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; must be low-impedance for accurate voltage monitoring. |
| 4 - PFI | Power-fail input | Monitors auxiliary voltage (e.g., via resistor divider); asserts PFO low when input falls below 1.237V. |
| 5 - PFO | Power-fail open-drain output | Signals undervoltage condition to µP interrupt line; can be tied to MR on compatible variants to trigger reset. |
| 6 - WDI | Watchdog input | Edge-sensitive input; reset triggered if no transition occurs within 1.6s - prevents firmware hang without manual intervention. |
| 7 - RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up, brownout, or watchdog timeout; guaranteed valid down to VCC = 1V. |
| 8 - VBATT | Backup battery input | Accepts 3.6V lithium cell; may exceed VCC; enables automatic switchover to preserve RAM when main supply fails. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | 3.075V ±75mV - matches 3.3V ±5% supply tolerance, preventing spurious resets while ensuring fail-safe behavior at 3.0V. |
| Guaranteed RESET assertion to VCC = 1V | Enables robust reset hold during deep brownouts where other supervisors lose functionality - critical for industrial control safety. |
| Battery switchover with 2.40V threshold | Triggers before VOUT drops below 2.0V, extending usable backup time and avoiding RAM data corruption in portable equipment. |
| 40µA VCC supply current | Reduces quiescent load on primary supply - extends battery life in always-on monitoring nodes and handheld instruments. |
| 1.6s watchdog timer with edge-clearing | Eliminates need for dedicated watchdog IC; tolerates µP sleep modes as long as periodic WDI toggling is maintained. |
Applications
| Battery-Powered Embedded Controller | Portable Data Logger |
|---|---|
Use Scenario: Industrial sensor node operating on AA batteries with intermittent wireless transmission and long sleep cycles. IC Role / Device Role / Timing Role: Supervises 3.3V LDO output, asserts RESET during battery sag, switches RAM to backup cell during transmission surge-induced brownout. Use Value: Prevents firmware crash and memory loss during transient voltage dips; enables >5-year field deployment without maintenance. |
Use Scenario: Handheld environmental logger capturing temperature/humidity every 10 seconds, powered by CR2032 coin cell. IC Role / Device Role / Timing Role: Monitors main 3.3V supply, triggers watchdog reset if sampling firmware hangs, maintains SRAM contents during battery replacement. Use Value: Eliminates need for external reset button or EEPROM-based state recovery; reduces BOM count by integrating reset, watchdog, and backup switching. |
| Intelligent Medical Instrument | Critical µP Power Monitoring |
Use Scenario: Portable blood glucose meter requiring FDA-grade reliability and zero data loss during battery insertion or low-voltage alerts. IC Role / Device Role / Timing Role: Provides deterministic reset timing at power-on, detects VCC drop below 3.0V, asserts PFO to alert user before measurement invalidation. Use Value: Meets IEC 62304 safety requirements for power-supply fault response; avoids false readings due to marginal supply conditions. |
Use Scenario: Programmable logic controller (PLC) CPU module where unexpected reset could halt production lines. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors 3.3V core rail and uses PFI to track 24V field bus voltage via resistor divider; generates PFO interrupt on undervoltage. Use Value: Enables predictive maintenance alerts and graceful shutdown instead of uncontrolled restart - minimizing downtime risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TCSA+ | Identical pinout and function, but includes manual reset (MR) input - adds user-initiated reset capability not present in MAX690TCSA+T. | Required where hardware reset button or remote reset signal is needed; unnecessary if only power/brownout supervision is required. | Select MAX704TCSA+ when MR functionality is needed; otherwise MAX690TCSA+T offers lower cost and same core supervision. |
| MAX802TCSA+ | Tighter reset threshold tolerance (±2% vs. ±75mV) and improved PFI accuracy (±2% vs. ±75mV) - higher precision for demanding industrial applications. | Suitable for systems requiring tighter voltage margins, such as high-reliability telecom or avionics subsystems with strict power validation. | Choose MAX802TCSA+ when design requires <±2% reset accuracy; MAX690TCSA+T suffices for general-purpose 3.3V embedded control. |
Compared with MAX704TCSA+, MAX690TCSA+T omits MR for cost-sensitive designs where manual reset is unnecessary; compared with MAX802TCSA+, it trades precision for broader tolerance and lower unit cost in non-critical applications.
Availability
MAX690TCSA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply across industrial temperature ranges and long-term production continuity.
Supply support for MAX690TCSA+T 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 consumer applications.
The MAX690 family was designed specifically for 3.0V/3.3V microprocessor systems needing integrated reset generation, watchdog monitoring, and battery-backed RAM preservation - targeting portable, embedded, and instrumentation markets.
FAQ
What is the exact reset threshold voltage for MAX690TCSA+T?
The MAX690TCSA+T has a nominal reset threshold of 3.075V when VCC is falling, with a guaranteed range of 3.00V to 3.15V. This value is specified for operation across 0°C to +70°C and ensures reliable reset assertion before the 3.3V supply degrades beyond system stability limits. The threshold exhibits 10mV typical hysteresis to prevent oscillation during slow VCC transitions.
Does MAX690TCSA+T support manual reset functionality?
No, MAX690TCSA+T does not include a manual reset (MR) input. Unlike the MAX704TCSA+ or MAX806TCSA+, the MAX690TCSA+T lacks the MR pin (Pin 6) and associated internal pull-up. Reset is triggered solely by VCC brownout, watchdog timeout, or power-fail condition - making it suitable for fully autonomous supervision without user intervention.
Can MAX690TCSA+T operate with a 3.0V supply instead of 3.3V?
Yes, MAX690TCSA+T supports VCC from 3.17V to 5.5V for the T-suffix variant, but its 3.075V reset threshold makes it compatible with 3.0V nominal systems that tolerate ±10% variation (i.e., 2.7V–3.3V). It will assert reset reliably when VCC falls below 3.00V, aligning with 3.0V system brownout protection requirements while maintaining compatibility with 3.3V designs.
How does the battery switchover work on MAX690TCSA+T?
MAX690TCSA+T switches VOUT from VCC to VBATT when VCC falls below the 2.40V battery switchover threshold (VSW) and VBATT exceeds VCC. The internal 140Ω switch connects VBATT to VOUT, preserving CMOS RAM data. Switchover back to VCC occurs only after VCC rises above the 3.075V reset threshold - ensuring stable supply reconnection and avoiding premature switching during recovery transients.
Is MAX690TCSA+T RoHS-compliant and lead-free?
Yes, MAX690TCSA+T is RoHS-compliant and lead-free, as indicated by the '+' suffix in the part number. It uses matte tin plating on the SOIC package leads and meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1), enabling standard reflow soldering without special handling. The '+' designation confirms compliance per Maxim Integrated's packaging standards.
MAX690TCSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 35ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX690TCSA+T FAQ
1.How can I place an order for MAX690TCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690TCSA+T 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 MAX690TCSA+T reliable?
The price and inventory of MAX690TCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690TCSA+T is usually 5 days.
3.What payment methods are accepted for MAX690TCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690TCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690TCSA+T?
MAX690TCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690TCSA+T 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 MAX690TCSA+T?
For technical support, including MAX690TCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690TCSA+T requirements.
6.How does Aetrix verify that MAX690TCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX690TCSA+T 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 MAX690TCSA+T meets industry standards.
7.What is the process for return or replacement of MAX690TCSA+T?
All MAX690TCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX690TCSA+T, 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 MAX690TCSA+T part is unused and in its original packaging.
Return procedure for MAX690TCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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