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Analog Devices Inc./Maxim Integrated MAX16021LTEM+
- Part No.:
- MAX16021LTEM+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
MAX16021LTEM+.pdf
- Description:
- IC SUPERVISOR PP 4.428V 16TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,356
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Product details
Overview
MAX16021LTEM+ from Maxim Integrated is a low-power microprocessor supervisory circuit with integrated battery-backup switchover, chip-enable (CE) gating, and multi-threshold power monitoring. It provides active-low reset output, 145ms minimum reset timeout, 1.2µA supply current (0.25µA in battery-backup mode), and supports 1.53V–5.5V VCC operation with fixed 3.100V typical reset threshold. It is used to protect SRAM/RTC data integrity during brownout in portable industrial GPS systems.
For engineers reviewing the MAX16021LTEM+ datasheet, MAX16021LTEM+ pinout, MAX16021LTEM+ application, or MAX16021LTEM+ equivalent, key selection criteria include its 16-pin TQFN package, push-pull reset output (denoted by 'L'), 3.100V reset threshold (suffix 'T'), CEIN/CEOUT propagation delay of 1.5ns, and battery-OK/battery-on indicator support for fail-safe RTC backup control.
Technical Context
The MAX16021LTEM+ implements a dual-path power-switching architecture: internal MOSFETs route either VCC or BATT to OUT based on real-time comparison of VCC against reset threshold and VBATT. Its CE gating logic locks CEIN transitions during reset assertion, holding CEOUT low for 12µs if CEIN is low at reset onset-ensuring write protection for CMOS memory before power collapse.
It integrates five independent supervisory functions: reset generation (with 20µs VCC-fall delay), watchdog timer (1.235s typical timeout), power-fail comparator (0.590V PFI threshold), low-line warning (LL asserted 2.5% above reset threshold), and battery health monitoring (BATTOK at 2.60V, BATT_TEST pulse every 24h).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.100V (typical), fixed threshold per suffix 'T' - ensures reliable µP reset at 3.3V system brownout |
| Reset Timeout Period | 145ms (min), 215ms (typ), 285ms (max) - guarantees sufficient hold time for µP initialization |
| Supply Current | 3.4µA (typ) at VCC = 5.5V; 0.25µA in battery-backup mode - enables multi-year RTC/SRAM retention on coin cell |
| VCC to OUT On-Resistance | 2.6Ω (typ) at VCC = 1.91V, IOUT = 10mA - minimizes voltage drop during main power delivery to memory |
| CEIN to CEOUT Propagation Delay | 1.5ns (typ), 7ns (max) - supports high-speed µP/DSP CE timing without external buffering |
| Watchdog Timeout | 0.83s (min), 1.235s (typ), 1.64s (max) - provides deterministic software hang detection for embedded firmware |
| Battery Switchover Threshold | VCC falling: 0mV offset vs VBATT - enables seamless transition to backup power at exact brownout point |
Pinout & Package
MAX16021LTEM+ uses a 16-pin 4mm × 4mm TQFN-EP package with exposed pad (EP) internally connected to GND. Thermal resistance θJA = 40°C/W enables operation at full spec over -40°C to +85°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 BATT | Backup battery input | Connects to coin cell; enables automatic switchover when VCC falls below reset threshold and VBATT > VCC |
| 2 MR | Active-low manual reset input | Internally pulled up to VCC (30kΩ); asserts reset on logic-low; debounced - no external RC needed |
| 3 PFI | Power-fail comparator input | Monitors scaled VCC via resistor divider; triggers PFO at 0.590V internal threshold with 30mV hysteresis |
| 4 WDI | Watchdog timer input | Rising/falling edge clears timer; timeout (1.235s typ) asserts WDO - disable by leaving floating or high-Z |
| 5 LL | Active-low low-line output | Asserts 2.5% above reset threshold (≈3.178V) - provides early NMI for orderly shutdown before reset |
| 6 RESET | Active-high reset output | Push-pull output (suffix 'L'); asserts high during VCC brownout or MR low - directly drives µP RESET# with no pull-up |
| 7 BATTOK | Battery-OK status indicator | Open-drain output; pulls low when VBATT < 2.60V - signals degraded backup power before failure |
| 8 BATTON | Battery-On status indicator | Active-high push-pull output; goes high only in battery-backup mode - confirms switchover completion |
| 9 WDO | Active-low watchdog output | Asserts low on WDI timeout; cleared on next WDI edge or reset - enables independent watchdog fault signaling |
| 10 PFO | Active-low power-fail output | Asserts low when PFI < 0.590V - indicates primary supply failure before reset initiation |
| 11 GND | Ground reference | Primary return path; EP must be soldered to large ground plane for thermal management (θJC = 6°C/W) |
| 12 RESET | Active-low reset output | Dual-reset pin configuration: second RESET is active-low variant - supports mixed µP interface requirements |
| 13 OUT | Switched output | Delivers VCC or BATT to memory; bypass with ≥0.1µF capacitor - powers SRAM/RTC during main power loss |
| 14 CEOUT | Active-low chip-enable output | Gated version of CEIN; held low for 12µs after reset onset if CEIN was low - prevents partial writes during brownout |
| 15 CEIN | Chip-enable input | Directly connects to µP CE#; passes through to CEOUT unless reset asserted - enables transparent memory access |
| 16 VCC | Main supply input | 1.53V–5.5V operation; bypass with 0.1µF capacitor - powers all internal circuits except battery-monitoring blocks |
Key Features
| Feature | Design Value |
|---|---|
| Integrated CE signal gating | 1.5ns CEIN→CEOUT propagation delay with 12µs reset hold - eliminates need for external latch in µP memory interfaces |
| Battery-freshness seal | 20nA max BATT leakage at VBATT = 5.5V - preserves shelf life of backup cells for >10 years |
| Low-line warning (LL) | 2.5% higher threshold than reset (3.178V typ) - delivers nonmaskable interrupt 10–100ms before reset for controlled firmware shutdown |
| UL® certification | IEC 60950-1 certified - meets safety requirements for industrial and medical equipment without additional isolation |
| Debounced manual reset | 120ns MR→RESET delay with internal 30kΩ pullup - supports direct switch-to-GND connection with no external components |
Applications
| GPS Tracking Units | Industrial PLC Memory Modules |
|---|---|
|
Use Scenario: Maintaining RTC and configuration SRAM during vehicle ignition cycling or antenna signal loss-induced brownouts. IC Role / Device Role / Timing Role: Supervisory controller providing VCC/BATT switchover, CE gating, and early low-line warning to trigger GPS position save before reset. Use Value: Prevents loss of last-known position and calibration data; enables cold-start recovery within 200ms of power restoration. |
Use Scenario: Protecting ladder-logic program storage in programmable logic controllers during factory line voltage sags. IC Role / Device Role / Timing Role: Dual-reset supervisor (active-high and active-low outputs) with CE lockout ensures atomic write cycles to nonvolatile memory during AC dropout. Use Value: Eliminates corrupted rungs or lost I/O state; supports 100% deterministic restart after 20ms–500ms interruptions. |
| Point-of-Sale Terminals | Portable Medical Monitors |
|
Use Scenario: Securing transaction logs and encryption keys in handheld POS devices during battery swap or USB power disconnect. IC Role / Device Role / Timing Role: Battery-OK (BATTOK) and Battery-On (BATTON) indicators coordinate with host MCU to initiate secure log flush before backup power depletion. Use Value: Guarantees PCI-DSS-compliant audit trail persistence; reduces risk of financial data loss during hot-swap events. |
Use Scenario: Preserving patient vital sign buffers and alarm history in battery-powered ECG monitors during AC adapter removal. IC Role / Device Role / Timing Role: Watchdog timer (1.235s timeout) and BATT_TEST pulse (1.3s every 24h) enable predictive battery health management without MCU intervention. Use Value: Extends clinical uptime by >15% via preemptive battery replacement alerts; maintains FDA 21 CFR Part 11 data integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisory circuit applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX16020LTEM+ | Identical pinout and electrical specs, but lacks BATT_TEST output - no periodic battery self-test pulse | Suitable where continuous battery health monitoring is not required; lower test overhead in firmware | Select MAX16020LTEM+ when BATT_TEST functionality is unnecessary and cost optimization is prioritized |
| TPS3808G33DBVR | Single-supply reset IC only (no battery switchover, no CE gating, no BATTOK/BATTON); 3.3V fixed threshold; SOT-23-6 package | Limited to basic reset generation in space-constrained designs without backup power or memory protection needs | Choose TPS3808G33DBVR only for simple 3.3V µP reset where battery backup and CE control are handled externally |
Compared with MAX16020LTEM+, MAX16021LTEM+ adds BATT_TEST for autonomous battery diagnostics; compared with TPS3808G33DBVR, it delivers full power-fail supervision, dual reset outputs, and integrated memory write protection - making it uniquely suited for battery-backed SRAM/RTC systems requiring zero-data-loss reliability.
Availability
MAX16021LTEM+ is available at Aetrix Electronics and suitable for GPS tracking units, industrial PLC memory modules, point-of-sale terminals, and portable medical monitors requiring stable component supply across extended product lifecycles.
Supply support for MAX16021LTEM+ 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) designs precision analog and mixed-signal ICs for industrial, automotive, and computing applications, with emphasis on power efficiency and system-level integration.
The MAX16021LTEM+ belongs to Maxim's µP supervisory family, engineered specifically for fail-safe data retention in battery-backed memory systems - combining reset, watchdog, power-fail detection, and CE gating in one compact TQFN package.
FAQ
What is the reset threshold voltage of the MAX16021LTEM+?
The MAX16021LTEM+ has a fixed reset threshold of 3.100V (typical), with min/max values of 3.010V and 3.190V respectively, as defined by the 'T' suffix in its ordering code. This threshold is factory-trimmed and guaranteed over -40°C to +85°C, enabling precise brownout detection in 3.3V systems without external resistor dividers.
Does the MAX16021LTEM+ support both active-high and active-low reset outputs?
Yes, the MAX16021LTEM+ provides dual reset outputs: pin 6 is an active-high RESET (push-pull, denoted by 'L' in the part number), and pin 12 is an active-low RESET. This allows simultaneous interfacing with µPs requiring either polarity, eliminating level-shifting components in mixed-architecture designs.
How does the CE gating function work in the MAX16021LTEM+?
In the MAX16021LTEM+, CEIN (pin 15) connects directly to CEOUT (pin 14) during normal operation. When reset asserts, CEOUT is held low for 12µs if CEIN was low at assertion time - ensuring memory write completion. After 12µs, CEOUT is actively pulled up to OUT, blocking further CE transitions until reset deasserts.
What is the purpose of the BATT_TEST output on the MAX16021LTEM+?
The BATT_TEST output (pin 6 on MAX16021, not present on MAX16020) pulses low for 1.3 seconds every 24 hours to activate an external load for battery voltage testing. If VBATT drops below 2.6V during this test, BATTOK deasserts - enabling predictive battery replacement before backup failure in mission-critical applications.
Can the MAX16021LTEM+ operate with a 1.8V main supply?
Yes, the MAX16021LTEM+ operates from 1.53V to 5.5V VCC, fully supporting 1.8V systems. Its reset threshold is fixed at 3.100V, so for 1.8V rails, it monitors a derived voltage (e.g., from a resistor divider off a higher auxiliary rail) rather than VCC directly - a common practice in low-voltage µP supervision.
MAX16021LTEM+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-WQFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.428V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High/Active Low
- Reset Timeout:
- 145ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TQFN (4x4)
MAX16021LTEM+ FAQ
1.How can I place an order for MAX16021LTEM+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX16021LTEM+ 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 MAX16021LTEM+ reliable?
The price and inventory of MAX16021LTEM+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX16021LTEM+ is usually 5 days.
3.What payment methods are accepted for MAX16021LTEM+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX16021LTEM+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX16021LTEM+?
MAX16021LTEM+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX16021LTEM+ 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 MAX16021LTEM+?
For technical support, including MAX16021LTEM+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX16021LTEM+ requirements.
6.How does Aetrix verify that MAX16021LTEM+ is sourced from the original manufacturer or authorized distributors?
All MAX16021LTEM+ 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 MAX16021LTEM+ meets industry standards.
7.What is the process for return or replacement of MAX16021LTEM+?
All MAX16021LTEM+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX16021LTEM+, 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 MAX16021LTEM+ part is unused and in its original packaging.
Return procedure for MAX16021LTEM+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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