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Analog Devices Inc./Maxim Integrated MAX861IUA+T
- Part No.:
- MAX861IUA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX861IUA+T.pdf
- Description:
- IC REG CHARG PUMP INV 50MA 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:9,995
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Product details
Overview
MAX861IUA+T from Maxim Integrated is a frequency-selectable, 50mA switched-capacitor voltage inverter/doubler IC designed for board-level DC-DC conversion without inductors. It operates from +1.5V to +5.5V (inverter) or +2.5V to +5.5V (doubler), delivers ≥87% efficiency at 50mA, features three user-selectable switching frequencies (13/100/250 kHz), and achieves 12Ω output resistance with 10µF low-ESR capacitors - ideal for portable medical instruments requiring compact, low-EMI negative rail generation.
For engineers reviewing the MAX861IUA+T datasheet, MAX861IUA+T pinout, MAX861IUA+T application, or MAX861IUA+T equivalent, key selection criteria include its 8-pin µMAX package, active-low shutdown (<1µA), LV pin configuration for mode selection, FC pin frequency control, and compatibility with legacy ICL7660/MAX660 footprints under modified biasing.
Technical Context
The MAX861IUA+T implements a BiCMOS charge-pump architecture with direct oscillator-to-switch coupling (no frequency division), enabling precise frequency control via the FC pin. Its internal switch resistance (RO ≈ 8Ω) combines with external capacitor ESR to define total output resistance (ROUT = RO + 4×ESRC1 + ESRC2 + 1/(fS×C1)).
Mode selection is determined by the LV pin: grounded for inverting operation (VOUT = –VIN), connected to OUT for doubling (VOUT = +2VIN). The active-low SHDN pin disables all internal circuitry, reducing supply current to <1µA while preserving reverse-current paths dependent on load topology.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 50mA continuous - supports op-amp bias rails and sensor analog front-ends without thermal derating in µMAX package. |
| Switching Frequencies | 13kHz / 100kHz / 250kHz - selectable via FC pin to optimize capacitor size (2.2–68µF) and minimize EMI in noise-sensitive signal chains. |
| Output Resistance | 12Ω typical - defines 600mV drop at 50mA load; enables predictable voltage regulation without feedback loop. |
| Quiescent Current | 200µA typical - ensures >90% efficiency across 1–50mA load range in battery-powered handheld instruments. |
| Shutdown Current | <1µA - allows system-level power gating without auxiliary circuitry; critical for low-duty-cycle medical sensors. |
| Input Voltage Range | +1.5V to +5.5V (inverter), +2.5V to +5.5V (doubler) - supports single-cell Li-ion, alkaline, and regulated 3.3V/5V rails. |
| Package | 8-pin µMAX (U8-1, 3mm × 3mm) - surface-mount footprint compatible with high-density portable PCB layouts. |
Pinout & Package
MAX861IUA+T uses an 8-pin µMAX package (3mm × 3mm, 1.11mm height) with exposed pad for thermal enhancement. Pin numbering follows standard SO/µMAX top-view convention (pin 1 at top-left corner, counterclockwise).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FC | Frequency Control input | Three-state logic input (VDD/GND/OUT) selects 13/100/250kHz oscillator frequency; no pull-up/down required. |
| C1+ | Flying capacitor positive terminal | Drives charge-transfer node for capacitor C1; requires low-ESR ceramic/tantalum (2.2–68µF) per selected frequency. |
| GND | Ground reference | Common return for VDD, OUT, and external capacitors; must be low-impedance plane to minimize ripple. |
| C1− | Flying capacitor negative terminal | Completes flying-capacitor switching path; connects directly to C1's negative lead with minimal trace length. |
| OUT | Inverted or doubled output | Delivers –VIN (LV = GND) or +2VIN (LV = OUT); output impedance dominated by ROUT = 12Ω + capacitor ESR effects. |
| LV | Mode selection input | Configures function: GND → inverter; OUT → doubler; floating allowed only for VIN >3V in inverter mode. |
| SHDN | Active-low shutdown | Pull to GND disables device (IDD <1µA); connect to VDD for permanent enable in inverter applications. |
| VDD | Positive supply input | Accepts +1.5V to +5.5V; bypass with 0.1µF ceramic if loaded VDD→OUT, or ≥10µF if loaded OUT→GND. |
Key Features
| Feature | Design Value |
|---|---|
| Three-frequency selection | Enables EMI avoidance in mixed-signal systems: 13kHz avoids audio band, 100kHz fits mid-range filtering, 250kHz minimizes capacitor size. |
| 12Ω output resistance | Provides predictable load regulation (e.g., –5.0V → –4.4V at 50mA) without closed-loop compensation components. |
| 1µA shutdown current | Permits integration into ultra-low-power wake-on-event architectures where supply rail remains active but converter is gated. |
| BiCMOS process | Delivers 200µA quiescent current and 87% efficiency at full load - superior to older CMOS charge pumps like ICL7660. |
| µMAX package | 3mm × 3mm footprint saves >60% board area vs. SO-8; exposed pad improves thermal performance for sustained 50mA output. |
Applications
| Portable Medical Sensors | Handheld Test Equipment |
|---|---|
Use Scenario: Powering low-noise instrumentation amplifiers in battery-operated ECG/EEG front-ends requiring clean ±5V rails. IC Role / Device Role / Timing Role: Generates stable –5V inverted rail from 5V main supply; FC pin set to 100kHz to avoid interference with 50Hz/60Hz mains rejection filters. Use Value: Eliminates inductor-based converters, reducing EMI that would corrupt microvolt-level bio-signals and enabling sub-10mm PCB thickness. | Use Scenario: Providing dual-rail supply for LCD bias and op-amp circuits in handheld multimeters with 200-hour battery life. IC Role / Device Role / Timing Role: Functions as voltage doubler (LV = OUT) to generate +10V from 5V battery; FC pin tied to GND for 100kHz operation balancing efficiency and capacitor cost. Use Value: Achieves 88% power efficiency at 20mA load, extending alkaline battery life while maintaining 3mm profile via µMAX package. |
| Operational Amplifier Bias Rails | Interface Power Supplies |
Use Scenario: Supplying ±3.3V rails for rail-to-rail op-amps in industrial sensor signal conditioning modules. IC Role / Device Role / Timing Role: Configured as inverter (LV = GND) to produce –3.3V from 3.3V input; FC pin left open for 13kHz mode minimizing quiescent current. Use Value: Delivers 200µA no-load current and 92% efficiency at 10mA, enabling always-on analog monitoring without thermal throttling. | Use Scenario: Generating isolated –5V for RS-232 transceivers in embedded controllers with shared 5V system rail. IC Role / Device Role / Timing Role: Acts as inverter with FC = OUT (250kHz) to reduce 10µF capacitor size and fit within tight layout constraints near connector. Use Value: Enables use of 0805-case 10µF X7R ceramics instead of larger tantalums, cutting BOM cost by 35% and improving reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor voltage converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX860IUA+T | Same package and pinout; offers 6/50/130kHz frequencies instead of 13/100/250kHz; 200µA IQ identical. | Better suited for ultra-low-noise audio applications needing 6kHz fundamental switching frequency. | Select MAX860IUA+T when EMI sensitivity demands sub-10kHz switching; otherwise MAX861IUA+T provides higher-frequency flexibility. |
| MAX660CPA+ | SO-8 package only; fixed 5kHz/40kHz dual-frequency; 100mA output; 6.5Ω ROUT; higher IQ (250µA). | Supports higher current loads but lacks frequency selectability and µMAX footprint. | Choose MAX660CPA+ only when 100mA output is mandatory and board space allows SO-8; MAX861IUA+T preferred for compact, frequency-tuned designs. |
Compared with MAX860IUA+T, MAX861IUA+T shifts all three frequencies upward (13/100/250kHz vs. 6/50/130kHz), improving capacitor miniaturization at the cost of slightly higher quiescent current in high-frequency mode; versus MAX660CPA+, it trades raw current capability for programmable frequency control and 40% smaller footprint.
Availability
MAX861IUA+T is available at Aetrix Electronics and suitable for portable medical instruments, handheld test equipment, operational-amplifier bias rails, and interface power supplies requiring stable component supply across extended temperature ranges (–25°C to +85°C).
Supply support for MAX861IUA+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 U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs for power, sensing, and connectivity applications.
The MAX860/MAX861 product line was engineered to replace legacy charge pumps (ICL7660, MAX660) with higher efficiency, lower quiescent current, and frequency-selectable operation - targeting space-constrained, battery-powered instrumentation.
FAQ
What is the maximum continuous output current specification for MAX861IUA+T?
The MAX861IUA+T is rated for 50mA continuous output current under specified thermal conditions (TA ≤ +70°C). Absolute maximum rating is 60mA, but sustained operation above 50mA may exceed the µMAX package's 362mW power dissipation limit. Derating is required above +70°C ambient, with 4.2mW/°C reduction applied to maintain reliability.
How does the LV pin configure MAX861IUA+T for inverting versus doubling operation?
The LV pin determines MAX861IUA+T's voltage conversion mode: connecting LV to GND configures it as an inverter (VOUT = –VIN), while connecting LV to OUT configures it as a doubler (VOUT = +2VIN). Floating LV is permitted only in inverter mode with VIN >3V to match legacy MAX660 behavior; for guaranteed operation across full temperature range, explicit GND or OUT connection is required.
What are the exact switching frequencies available on MAX861IUA+T and how are they selected?
MAX861IUA+T offers three nominal switching frequencies: 13kHz (FC = VDD or open), 100kHz (FC = GND), and 250kHz (FC = OUT). These values are confirmed in Table 1 of the datasheet and verified across the –25°C to +85°C operating range. Frequency selection is implemented via direct logic-level connection - no external resistors or timing components are needed.
Can MAX861IUA+T replace ICL7660 or MAX660 in existing designs without PCB changes?
MAX861IUA+T is pin-compatible with ICL7660 and MAX660 in 8-pin SO packages but requires one wiring change in µMAX: the OSC pin (pin 1) on legacy devices maps to FC on MAX861IUA+T, and the SHDN pin (pin 7) replaces the unused OSC pull-down. For SO designs, direct replacement is possible with SHDN tied to VDD; for µMAX, FC routing must be updated to leverage frequency selectability.
What is the output resistance of MAX861IUA+T and how does it affect load regulation?
MAX861IUA+T has a typical output resistance (ROUT) of 12Ω when used with 10µF, 0.2Ω ESR capacitors at 100kHz. This results in a 600mV voltage drop at 50mA load (e.g., –5.0V → –4.4V), enabling predictable load regulation without feedback. ROUT varies with frequency, capacitor ESR, and temperature - detailed curves are provided in Figures MAX860-03 and MAX860-04 of the datasheet.
MAX861IUA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Ratiometric
- Output Configuration:
- Positive or Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.5V, 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- -Vin, 2Vin
- Voltage - Output (Max):
- -
- Current - Output:
- 50mA
- Frequency - Switching:
- 13kHz, 100kHz, 250kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX861IUA+T FAQ
1.How can I place an order for MAX861IUA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX861IUA+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 MAX861IUA+T reliable?
The price and inventory of MAX861IUA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX861IUA+T is usually 5 days.
3.What payment methods are accepted for MAX861IUA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX861IUA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX861IUA+T?
MAX861IUA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX861IUA+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 MAX861IUA+T?
For technical support, including MAX861IUA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX861IUA+T requirements.
6.How does Aetrix verify that MAX861IUA+T is sourced from the original manufacturer or authorized distributors?
All MAX861IUA+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 MAX861IUA+T meets industry standards.
7.What is the process for return or replacement of MAX861IUA+T?
All MAX861IUA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX861IUA+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 MAX861IUA+T part is unused and in its original packaging.
Return procedure for MAX861IUA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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