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Analog Devices Inc./Maxim Integrated MAX690TESA
- Part No.:
- MAX690TESA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690TESA.pdf
- Description:
- IC SUPERVISOR MAX690 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:3,783
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Product details
Overview
MAX690TESA from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-low RESET output, 3.075V reset threshold (T-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover. It monitors VCC for brownout detection, asserts reset during power-up/down, and switches VOUT to VBATT when VCC falls below 2.40V - used in battery-backed embedded controllers requiring reliable power sequencing and RAM retention.
For engineers reviewing the MAX690TESA datasheet, MAX690TESA pinout, MAX690TESA application, or MAX690TESA equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed operating conditions (0°C to +70°C), and real-world use cases in portable instrumentation and critical µP systems where supply-voltage monitoring and fail-safe reset timing are essential.
Technical Context
The MAX690TESA integrates a precision reset comparator with ±4% threshold tolerance, a non-disableable 1.6s watchdog timer cleared by WDI edges, and a dual-path power-switching circuit: VCC-to-VOUT via a 3Ω PMOS switch and VBATT-to-VOUT via a 140Ω switch activated at VSW = 2.40V. Its PFI/PFO pair provides independent power-fail detection referenced to 1.237V with 10mV hysteresis.
It operates across VCC = 3.17V–5.5V (T-version), supports battery voltage exceeding VCC, guarantees RESET assertion down to VCC = 1V, and features 40µA VCC supply current (typ) and 1µA VBATT leakage (max) - enabling long-term backup operation without compromising system quiescent power.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (VCC falling), ±4% tolerance - ensures reset triggers before 3.3V supply drops below 3.0V system margin. |
| Reset Timeout Period | 200ms (typ), 140–280ms range - provides sufficient deassertion delay for µP initialization after stable VCC recovery. |
| Watchdog Timeout | 1.6s (typ), 1.12–2.24s range - detects µP lockup without requiring software intervention or external timing components. |
| VCC Supply Current | 40µA (typ) at VCC < 3.6V - enables low-power operation in always-on battery-backed systems. |
| Battery Leakage Current | 0.01–0.5µA (max) - preserves lithium cell life over multi-year standby periods. |
| VBATT Switch Threshold | VSW = 2.40V (rising), 65mV hysteresis - initiates battery switchover early enough to maintain CMOS RAM above 2.0V minimum. |
| PFO Input Threshold | 1.237V ±25mV - allows accurate external supply monitoring via resistor divider without calibration. |
Pinout & Package
MAX690TESA is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with 1.27mm pitch and standard JEDEC MS-012AC outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch) based on VCC/VBATT comparison - maintains RAM voltage during brownout. |
| VCC | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and defines reset comparator reference; accepts 3.17–5.5V range. |
| GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC or VBATT. |
| PFI | Power-fail input | Monitors external supply via resistor divider; triggers PFO low when voltage falls below 1.237V - enables secondary supply monitoring. |
| PFO | Power-fail output | Open-drain active-low signal indicating PFI undervoltage or VCC < VSW - can be wired to MR for cascaded reset initiation. |
| WDI | Watchdog input | Edge-sensitive input (rising/falling); clears 1.6s timer on transition - requires periodic µP toggling to prevent watchdog reset. |
| RESET | Active-low reset output | Push-pull output asserted low during power-up, brownout, or watchdog timeout; guaranteed valid down to VCC = 1V. |
| VBATT | Backup-battery input | Accepts up to 6.0V; connects to VOUT when VCC falls below VSW; enables lithium cells (e.g., 3.6V) to exceed VCC without diode loss. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures reliable reset signaling even during deep brownout, preventing µP execution from corrupted memory. |
| Battery-backup switchover with VCC > VBATT support | Eliminates need for external diode or MOSFET, reducing BOM count and forward-voltage drop in RAM backup path. |
| 200ms reset timeout with restart-on-brownout | Provides deterministic reset hold time while automatically extending assertion if VCC dips again - avoids spurious release. |
| 1.237V PFI threshold with 10mV hysteresis | Enables precise, noise-immune monitoring of auxiliary supplies (e.g., 5V, -12V) using simple resistor dividers. |
| Non-disableable watchdog timer | Prevents accidental firmware disable of safety-critical supervision - mandatory for industrial and medical applications. |
Applications
| Battery-Powered Embedded Controller | Critical µP Power Monitoring |
|---|---|
|
Use Scenario: Portable data logger with SRAM retention during main power interruption. IC Role / Device Role / Timing Role: Supervisory IC providing VCC brownout detection, automatic VBATT switchover to VOUT, and 200ms RESET hold to ensure µP reset completion. Use Value: Preserves RAM contents for >10 years using 3.6V lithium coin cell; eliminates external diode and timing capacitor. |
Use Scenario: Industrial PLC module requiring fail-safe startup and runtime watchdog supervision. IC Role / Device Role / Timing Role: Dual-role supervisor: reset generator during power-up and watchdog monitor during operation via WDI toggling. Use Value: Prevents runaway code execution; guarantees µP enters known state on any supply anomaly - meets IEC 61508 SIL-2 requirements. |
| Intelligent Instrumentation | Portable Medical Device |
|
Use Scenario: Handheld multimeter with EEPROM configuration storage and real-time clock backup. IC Role / Device Role / Timing Role: Precision voltage monitor (3.075V threshold) and PFI-based power-fail warning for graceful shutdown sequence. Use Value: Triggers PFO-driven interrupt to save settings before VCC collapse; 1.237V PFI reference enables accurate 5V rail monitoring. |
Use Scenario: Wearable ECG monitor powered by rechargeable Li-ion with SRAM-based waveform buffer. IC Role / Device Role / Timing Role: Battery switchover controller and watchdog enforcer ensuring continuous data capture during charging interruptions. Use Value: 40µA quiescent current extends battery runtime; 1µA VBATT leakage prevents cell discharge during 6-month shelf life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TESA | Identical pinout, same 3.075V reset threshold and 200ms timeout, but adds manual reset (MR) input with 70µA pull-up. | Required where hardware-initiated reset (e.g., front-panel button) is needed alongside power supervision. | Select MAX704TESA if MR functionality is required; otherwise MAX690TESA offers simpler interface and identical core supervision. |
| MAX802TESA | Tighter reset threshold tolerance (±2% vs. ±4%) and improved PFI accuracy (±2% vs. ±4%), same 3.075V nominal threshold. | Suitable for high-precision 3.3V systems where supply margin is constrained (e.g., FPGA-based designs with tight VCCINT specs). | Choose MAX802TESA when tighter voltage monitoring is mandated; MAX690TESA remains optimal for cost-sensitive, general-purpose µP supervision. |
Compared with MAX704TESA and MAX802TESA, the MAX690TESA provides foundational supervision (reset, watchdog, battery switchover) without MR or enhanced accuracy - making it ideal for space-constrained, low-cost embedded systems where those extended features are unnecessary.
Availability
MAX690TESA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instrumentation, and critical µP power monitoring requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX690TESA 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 MAX690 series was designed specifically for 3.0V/3.3V microprocessor systems needing integrated reset generation, watchdog supervision, and seamless battery-backup switchover - targeting portable, embedded, and instrumentation markets.
FAQ
What is the reset threshold voltage for MAX690TESA?
The MAX690TESA has a nominal reset threshold of 3.075V (VCC falling), with ±4% tolerance (3.00V to 3.15V). This value is fixed by the 'T' suffix and optimized for 3.3V systems with ±5% supply tolerance. The threshold is guaranteed to assert reset before VCC falls below 3.0V and remains valid down to VCC = 1V, ensuring robust brownout protection across the full operating temperature range (0°C to +70°C).
Does MAX690TESA support battery voltage higher than VCC?
Yes, MAX690TESA explicitly supports VBATT exceeding VCC - a key design feature enabling direct connection of 3.6V lithium batteries without external diodes. The internal battery switchover circuit activates when VCC falls below VSW = 2.40V (with 65mV hysteresis), connecting VBATT to VOUT through a 140Ω switch. This architecture eliminates forward-voltage drop and simplifies backup power design in portable equipment using MAX690TESA.
How does the watchdog timer function in MAX690TESA?
The MAX690TESA watchdog timer has a fixed 1.6s timeout (1.12–2.24s range) and cannot be disabled. It resets the internal counter on any rising or falling edge at the WDI pin. If WDI remains static (high or low) beyond the timeout, RESET is asserted. During RESET assertion, the timer is held cleared. This behavior ensures continuous µP activity monitoring in safety-critical applications using MAX690TESA, with no software or configuration dependency.
Can MAX690TESA operate without a backup battery?
Yes, MAX690TESA can operate without a backup battery: connect both VBATT and VOUT pins directly to VCC. In this configuration, the device retains full reset supervision, watchdog, and power-fail monitoring functions. However, battery switchover and RAM backup capability are disabled. For pure supervision-only applications without backup needs, MAX690TESA remains fully functional and electrically stable - no additional components are required beyond decoupling capacitors.
What is the purpose of the PFI and PFO pins on MAX690TESA?
The PFI (Power-Fail Input) and PFO (Power-Fail Output) pins on MAX690TESA provide an independent voltage-monitoring channel referenced to 1.237V ±25mV. PFI accepts external divided voltages (e.g., from 5V or -12V rails); when PFI falls below threshold, PFO goes low. PFO can drive interrupts or be connected to MR on compatible parts (e.g., MAX704) to trigger reset. This dual-function block extends MAX690TESA's utility beyond primary VCC monitoring into multi-rail system supervision.
MAX690TESA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX690TESA FAQ
1.How can I place an order for MAX690TESA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690TESA 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 MAX690TESA reliable?
The price and inventory of MAX690TESA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690TESA is usually 5 days.
3.What payment methods are accepted for MAX690TESA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690TESA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690TESA?
MAX690TESA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690TESA 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 MAX690TESA?
For technical support, including MAX690TESA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690TESA requirements.
6.How does Aetrix verify that MAX690TESA is sourced from the original manufacturer or authorized distributors?
All MAX690TESA 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 MAX690TESA meets industry standards.
7.What is the process for return or replacement of MAX690TESA?
All MAX690TESA units undergo pre-shipment inspection (PSI). If there is an issue with MAX690TESA, 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 MAX690TESA part is unused and in its original packaging.
Return procedure for MAX690TESA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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