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Analog Devices Inc./Maxim Integrated MAX921CUA+
- Part No.:
- MAX921CUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Comparators
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX921CUA+.pdf
- Description:
- IC COMPARATOR 1 W/VOLT REF 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:115
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Product details
Overview
The MAX921CUA+ from Maxim Integrated is a single-channel, ultra-low-power voltage comparator with integrated 1.182V ±1% bandgap reference, programmable hysteresis via HYST pin, and TTL/CMOS-compatible output capable of sourcing up to 40mA. It operates from +2.5V to +11V single supply (or ±1.25V to ±5.5V dual supply), features 4μA max quiescent current over 0°C to +70°C, and supports rail-to-rail input common-mode range down to V− and within 1.3V of V+. It is used in battery-powered threshold detection where low standby power and internal reference simplify design.
For engineers reviewing the MAX921CUA+ datasheet, MAX921CUA+ pinout, MAX921CUA+ application, or MAX921CUA+ equivalent, key selection criteria include guaranteed 4μA supply current at +70°C, internal reference accuracy (±1%), hysteresis configurability without external feedback, 12μs propagation delay at 10mV overdrive, and μMAX-8 package compatibility with space-constrained portable systems.
Technical Context
The MAX921CUA+ integrates a micropower comparator core and a precision 1.182V bandgap reference referenced to V−, not GND. Its unique output stage eliminates crowbar current during transitions, minimizing supply-line parasitic feedback and enabling stable operation without strict layout constraints.
Input common-mode range extends from V− to (V+ − 1.3V); inputs tolerate −0.3V to (V+ + 0.3V). The HYST pin accepts 1.132V–1.182V (REF − 50mV to REF) to set symmetric hysteresis bands up to 100mV, with hysteresis applied directly to the comparator's internal threshold without external resistive networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +2.5V to +11V single supply (or ±1.25V to ±5.5V dual supply) - enables direct use in 3V/5V systems and bipolar signal monitoring. |
| Quiescent Supply Current | ≤4μA over 0°C to +70°C - ensures multi-year battery life in always-on sensor nodes and portable instruments. |
| Reference Voltage | 1.182V ±1% (0°C to +70°C) referenced to V− - provides stable, factory-trimmed threshold without external components. |
| Propagation Delay | 12μs at 10mV overdrive - supports reliable timing-critical window detection and oscillator circuits up to ~10kHz. |
| Output Drive Capability | Sources ≥40mA continuously (V+ = 5V); sinks ≥1.8mA - directly drives LEDs, small relays, or logic inputs without buffer stages. |
| Input Offset Voltage | ±10mV - defines minimum detectable differential for precision thresholding in low-voltage analog sensing. |
| Input Common-Mode Range | V− to (V+ − 1.3V) - allows full-rail input operation in single-supply configurations, e.g., detecting 0–3.3V signals with 3.3V supply. |
Pinout & Package
Package: 8-pin μMAX (3mm × 3mm, 0.5mm pitch), thermally enhanced, lead-free, RoHS-compliant surface-mount package optimized for high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | GND | Ground reference; connects to V− for single-supply operation; output swings from V+ to GND. |
| 2 | V− | Negative supply rail; tied to GND in single-supply mode; reference and comparator bias referenced to this node. |
| 3 | IN+ | Noninverting input; accepts signals from V− to (V+ − 1.3V); high-impedance (±0.01nA leakage). |
| 4 | IN− | Inverting input; same voltage range and leakage as IN+; forms differential pair with IN+. |
| 5 | HYST | Hysteresis control input; voltage between REF − 50mV and REF sets hysteresis band (up to 100mV). |
| 6 | REF | 1.182V ±1% reference output referenced to V−; sources up to 25μA (TA = +25°C); must not be bypassed. |
| 7 | V+ | Positive supply rail; supports up to +11V; powers comparator core and output stage. |
| 8 | OUT | Push-pull output; sinks and sources current; swings fully from V+ to GND; TTL/CMOS compatible at +5V supply. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 4μA max over 0°C to +70°C - enables >10-year battery life in coin-cell–powered IoT sensors. |
| Integrated precision reference | 1.182V ±1% (0°C to +70°C), referenced to V− - eliminates need for external voltage reference IC or resistor divider. |
| Programmable hysteresis | Hysteresis band up to 100mV set via HYST pin voltage (REF − 50mV to REF) - avoids instability in noisy environments without feedback resistors. |
| No crowbar switching current | Eliminates supply-line glitches during output transitions - prevents false triggering in shared power domains and simplifies decoupling. |
| High-output drive capability | 40mA continuous source current - directly interfaces with LEDs, optocouplers, or logic gates without external drivers. |
Applications
| Battery-Powered Threshold Detector | Auto-Off Power Switch |
|---|---|
|
Use Scenario: Detecting low battery voltage in handheld medical devices to trigger shutdown before critical brownout. IC Role / Device Role / Timing Role: Single comparator compares battery voltage against internal 1.182V reference scaled by resistor divider; HYST pin adds 50mV hysteresis to prevent chatter near cutoff. Use Value: Eliminates external reference and hysteresis resistors, reducing BOM count by 3–4 components while maintaining <±1% trip accuracy across temperature. |
Use Scenario: Enabling timed auto-shutdown in portable test equipment after user inactivity. IC Role / Device Role / Timing Role: MAX921CUA+ output drives MOSFET gate; RC network on HYST pin sets 92-second timeout window before power removal. Use Value: Achieves 3.5μA total system quiescent current using only one IC and two passive components - extends shelf life of sealed battery packs. |
| LED Bar-Graph Level Indicator | Single-Supply Level Shifter |
|
Use Scenario: Visual battery charge level indication in rechargeable power tools using four discrete LED segments. IC Role / Device Role / Timing Role: Four identical MAX921CUA+ comparators (one per LED) compare scaled battery voltage against stepped reference thresholds derived from REF. Use Value: Each MAX921CUA+ sources 20mA directly into LED anodes - no current-limiting transistors or driver ICs required, saving 8–12 mm² PCB area per channel. |
Use Scenario: Converting ±5V analog sensor outputs (e.g., strain gauge bridge) to 0V/5V logic levels for microcontroller ADC input. IC Role / Device Role / Timing Role: Comparator compares bipolar input against 0V (GND) with REF used as stable 1.182V offset to define zero-crossing point. Use Value: Internal reference replaces external op-amp level-shifting circuitry; single-supply operation avoids dual-rail power design complexity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV331IDBVR | No internal reference; requires external 1.2V reference; 55μA supply current; rail-to-rail input; 150ns propagation delay. | Higher power consumption limits use in multi-year battery applications; lacks integrated hysteresis control. | Select when faster response (<200ns) is required and external reference is already present in system. |
| LMV331M5X | No internal reference; 100μA supply current; open-drain output; no hysteresis pin; 200ns propagation delay. | Cannot source current - requires pull-up resistor; unsuitable for direct LED driving or auto-off switch loads. | Select for cost-sensitive, non-battery applications where open-drain interface matches existing logic bus architecture. |
Compared with TLV331IDBVR and LMV331M5X, the MAX921CUA+ uniquely combines ultra-low 4μA supply current, integrated ±1% reference, and programmable hysteresis in a single μMAX-8 package - making it the only option that simultaneously satisfies multi-year battery life, component count reduction, and noise-immune threshold detection.
Availability
MAX921CUA+ is available at Aetrix Electronics and suitable for battery-powered instrumentation, portable medical monitors, and industrial sensor nodes requiring stable component supply with long-term lifecycle support.
Supply support for MAX921CUA+ 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 power, sensing, and interface applications in industrial, automotive, and communications markets.
The MAX921CUA+ belongs to the MAX921–MAX924 family of ultra-low-power comparators engineered specifically for energy-constrained systems needing integrated references and robust noise immunity without external components.
FAQ
What is the maximum operating supply voltage for the MAX921CUA+?
The MAX921CUA+ supports a single-supply voltage range of +2.5V to +11V. When operated from dual supplies, it accepts ±1.25V to ±5.5V. Absolute maximum ratings specify V+ to V− ≤ +12V and V+ to GND ≤ +12V. Exceeding these may cause permanent damage. The MAX921CUA+ is rated for commercial temperature range (0°C to +70°C) and is not specified for operation above +11V.
Does the MAX921CUA+ require external hysteresis components?
No - the MAX921CUA+ includes a dedicated HYST pin that accepts a voltage between REF − 50mV and REF to configure hysteresis without external feedback resistors. Connecting HYST to REF disables hysteresis. This feature eliminates the need for positive-feedback networks, reduces component count, and avoids stability issues associated with high-impedance external hysteresis paths.
Can the MAX921CUA+ drive an LED directly?
Yes - the MAX921CUA+ output can source up to 40mA continuously (at V+ = 5V), which is sufficient to drive standard 20mA LEDs directly. For example, with a 5V supply and red LED (VF ≈ 1.8V), a 150Ω series resistor limits current to ~21mA. No external transistor or driver IC is needed, simplifying board layout and reducing BOM cost.
Is the internal reference of the MAX921CUA+ referenced to GND or V−?
The internal 1.182V reference of the MAX921CUA+ is referenced to V−, not GND. In single-supply operation where V− = GND, REF = 1.182V relative to GND. In dual-supply operation (e.g., V+ = +5V, V− = −5V), REF = −5V + 1.182V = −3.818V relative to GND. This design ensures consistent reference behavior across both supply configurations.
What is the typical propagation delay of the MAX921CUA+ at 10mV overdrive?
The MAX921CUA+ exhibits a typical propagation delay of 12μs when driven with 10mV overdrive (i.e., input differential exceeds threshold by 10mV), measured under standard conditions (V+ = 5V, V− = GND, TA = +25°C, 100pF load). This value is confirmed in the Electrical Characteristics table and Typical Operating Characteristics plots of the official MAX921–MAX924 datasheet.
MAX921CUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- with Voltage Reference
- Number of Elements:
- 1
- Output Type:
- CMOS, TTL
- Voltage - Supply, Single/Dual (±):
- 2.5V ~ 11V, ±1.25V ~ 5.5V
- :
- 10mV @ 5V
- Voltage - Input Offset (Max):
- -
- Current - Input Bias (Max):
- 50mA
- Current - Output (Typ):
- 5µA
- Current - Quiescent (Max):
- 80dB CMRR, 80dB PSRR
- CMRR, PSRR (Typ):
- 12µs
- Propagation Delay (Max):
- 50mV
- Hysteresis:
- 0°C ~ 70°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 8-uMAX/uSOP
MAX921CUA+ FAQ
1.How can I place an order for MAX921CUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX921CUA+ 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 MAX921CUA+ reliable?
The price and inventory of MAX921CUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX921CUA+ is usually 5 days.
3.What payment methods are accepted for MAX921CUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX921CUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX921CUA+?
MAX921CUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX921CUA+ 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 MAX921CUA+?
For technical support, including MAX921CUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX921CUA+ requirements.
6.How does Aetrix verify that MAX921CUA+ is sourced from the original manufacturer or authorized distributors?
All MAX921CUA+ 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 MAX921CUA+ meets industry standards.
7.What is the process for return or replacement of MAX921CUA+?
All MAX921CUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX921CUA+, 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 MAX921CUA+ part is unused and in its original packaging.
Return procedure for MAX921CUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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