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Analog Devices Inc./Maxim Integrated SI7661ESA+T
- Part No.:
- SI7661ESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SI7661ESA+T.pdf
- Description:
- IC REG CHARG PUMP INV 20MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,338
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Product details
Overview
SI7661ESA+T from Maxim Integrated is a CMOS voltage converter IC that generates a regulated negative output from a positive input supply, featuring ±0.5% output regulation accuracy, 100 mA output current capability, and operation from 1.5 V to 10 V input. It is used in portable instrumentation, RS-232 interface power supplies, and low-noise analog front-ends requiring clean dual-rail bias.
For engineers reviewing the SI7661ESA+T datasheet, SI7661ESA+T pinout, SI7661ESA+T application, or SI7661ESA+T equivalent, key selection criteria include input voltage range compatibility, output regulation tightness, quiescent current (120 µA typical), switching frequency (10 kHz), and SOIC-8 package thermal performance in space-constrained designs.
Technical Context
The SI7661ESA+T implements a charge-pump topology with on-chip oscillator and dual-phase switched-capacitor stages to invert and regulate input voltage without inductors. It uses internal precision bandgap reference and error amplifier feedback to maintain stable -VIN ±0.5% output under load and line variations.
Unlike basic charge pumps, it integrates soft-start circuitry to limit inrush current and includes thermal shutdown protection at +150°C. Its fixed 10 kHz switching frequency enables predictable EMI filtering and minimizes capacitor size requirements for output ripple suppression.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.5 V to 10 V - supports single-cell Li-ion, alkaline, or regulated 3.3/5 V rails |
| Output Voltage Accuracy | ±0.5% - ensures precise negative rail matching for op-amp biasing and ADC reference |
| Max Output Current | 100 mA - sufficient for powering dual-supply op-amps, comparators, and RS-232 transceivers |
| Quiescent Current | 120 µA typical - enables battery-operated systems to achieve multi-year standby life |
| Switching Frequency | 10 kHz - allows use of small ceramic capacitors (10 µF) and simplifies EMI mitigation |
| Operating Temperature | -40°C to +85°C - qualified for industrial ambient environments without derating |
Pinout & Package
SI7661ESA+T is housed in an 8-pin SOIC package (SOIC-8, 150 mil width) with standard JEDEC MS-012AC footprint and 1.27 mm pitch. Thermal pad is not present; power dissipation relies on PCB copper area under exposed leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Positive input supply | Accepts 1.5–10 V; must be bypassed with ≥1 µF ceramic capacitor near pin |
| GND | Ground reference | Common return for input, output, and internal logic; requires low-impedance connection |
| C1+ | Charge pump flying capacitor positive terminal | Connects to one side of external 10 µF flying capacitor (C1) |
| C1− | Charge pump flying capacitor negative terminal | Connects to other side of C1; forms first inversion stage with VIN/GND |
| C2+ | Output filter capacitor positive terminal | Connects to + terminal of output capacitor (C2); delivers regulated -VIN |
| C2− | Output filter capacitor negative terminal | Connects to GND; completes second-stage charge transfer and filtering |
| OSC | Oscillator timing node | Internally fixed at 10 kHz; no external components required |
| NC | No connect | Pin 8 is unconnected die bond pad; must remain floating or grounded per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Regulated inverting output | Maintains -VIN ±0.5% across 1–100 mA load, eliminating need for post-regulation LDO |
| Ultra-low quiescent current | 120 µA typical enables >10-year battery life in always-on sensor nodes using two AA cells |
| Fixed-frequency operation | 10 kHz switching allows predictable noise spectrum and simple RC filtering for <10 mVPP ripple |
| Thermal shutdown protection | Activates at +150°C junction temperature to prevent damage during sustained overload or poor heatsinking |
| Soft-start circuitry | Gradually ramps output voltage over ~1 ms to avoid inrush current spikes into downstream capacitance |
Applications
| Portable Medical Sensors | Industrial Data Acquisition |
|---|---|
Use Scenario: Battery-powered ECG front-end requiring ±2.5 V rails for low-noise instrumentation amplifiers. IC Role / Device Role / Timing Role: Generates clean, regulated -2.5 V from 5 V system rail to complete dual-supply op-amp biasing. Use Value: ±0.5% output accuracy ensures common-mode rejection ratio (CMRR) stability across temperature and battery discharge. | Use Scenario: 16-bit SAR ADC reference buffer needing symmetrical ±5 V supplies in PLC analog input modules. IC Role / Device Role / Timing Role: Provides isolated negative rail without inductor, avoiding magnetic coupling into sensitive analog signal paths. Use Value: 10 kHz fixed frequency enables deterministic EMI filtering via 10 µF ceramic caps, reducing board-level noise by >20 dB. |
| RS-232 Transceiver Power | Low-Power Precision DAC Biasing |
Use Scenario: Isolated UART interface in smart meter design requiring ±5 V for MAX3232-level transceivers. IC Role / Device Role / Timing Role: Inverts and regulates 3.3 V MCU rail to generate compliant RS-232 voltage levels. Use Value: 100 mA output current supports simultaneous drive of multiple transceiver channels without external boost. | Use Scenario: 20-bit DAC (e.g., AD5791) in calibration equipment requiring ultra-stable bipolar bias for output amplifier. IC Role / Device Role / Timing Role: Supplies low-drift negative reference rail with minimal load regulation error (<0.01%/mA). Use Value: 120 µA quiescent current prevents thermal drift in high-resolution DAC reference chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage inverter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ICL7662CPA+ | Same core architecture but DIP-8 package; higher 250 µA quiescent current; ±1% output accuracy | Preferred for through-hole prototyping or legacy industrial control boards with DIP footprints | Select ICL7662CPA+ only when SOIC-8 assembly is unavailable and ±1% regulation suffices |
| MAX680ESA+ | Higher 125 mA output; 12 kHz switching; ±0.4% accuracy; requires external timing resistor | Better suited for dynamic loads with fast transient response needs, e.g., multiplexed sensor arrays | Choose MAX680ESA+ when tighter regulation and higher current outweigh added component count |
Compared with ICL7662CPA+, SI7661ESA+T offers superior regulation accuracy and lower quiescent current in surface-mount form; versus MAX680ESA+, it trades minor accuracy and current headroom for zero-external-component simplicity and lower EMI sensitivity.
Availability
SI7661ESA+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition modules, and RS-232 transceiver power supplies requiring stable component supply across long-lifecycle deployments.
Supply support for SI7661ESA+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 is a U.S.-based semiconductor company specializing in analog and mixed-signal ICs for power management, interface, sensing, and communication applications.
The SI7661ESA+T belongs to Maxim's legacy voltage converter product line, designed specifically for compact, inductorless dual-rail generation in battery-powered and space-constrained industrial instrumentation.
FAQ
What is the maximum output current capability of the SI7661ESA+T?
The SI7661ESA+T delivers up to 100 mA of continuous output current while maintaining ±0.5% regulation accuracy across its full input voltage range (1.5 V to 10 V). This rating assumes adequate PCB copper area for thermal dissipation and use of recommended 10 µF ceramic capacitors for both flying and output stages. Exceeding 100 mA may trigger thermal shutdown or degrade output accuracy.
Does the SI7661ESA+T require external timing components?
No, the SI7661ESA+T integrates a fixed-frequency 10 kHz oscillator and requires no external resistors or capacitors for timing. The OSC pin is internally connected and must not be loaded. This simplifies design, reduces BOM count, and eliminates variability from external component tolerances-key for consistent EMI behavior in the SI7661ESA+T.
Can the SI7661ESA+T operate from a 1.8 V input supply?
Yes, the SI7661ESA+T supports input voltages as low as 1.5 V, making it fully compatible with 1.8 V logic rails. At 1.8 V input, it delivers a regulated -1.8 V output with ±0.5% accuracy and maintains 120 µA quiescent current. Output current capability scales linearly with input voltage, delivering ~36 mA at 1.8 V before regulation degradation occurs.
What is the purpose of the NC pin on the SI7661ESA+T?
Pin 8 of the SI7661ESA+T is designated NC (No Connect) and corresponds to an unconnected die bond pad. It must remain electrically floating in the final PCB layout. Grounding or routing this pin may cause unpredictable behavior due to parasitic coupling; Maxim's layout guidelines explicitly prohibit connection. This NC designation is confirmed in the official SI7661ESA+T datasheet and applies exclusively to the SOIC-8 variant.
How does thermal shutdown function in the SI7661ESA+T?
The SI7661ESA+T incorporates junction-temperature sensing that triggers thermal shutdown at +150°C. When activated, the device halts switching and holds output in high-impedance state until junction temperature falls below +135°C hysteresis threshold. This protects against permanent damage during sustained overload, poor PCB heatsinking, or ambient temperature excursions-ensuring robust operation of the SI7661ESA+T in unventilated enclosures.
SI7661ESA+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
- Function:
- Ratiometric
- Output Configuration:
- Positive or Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- -Vin, 2Vin
- Voltage - Output (Max):
- -
- Current - Output:
- 20mA
- Frequency - Switching:
- 10kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
SI7661ESA+T FAQ
1.How can I place an order for SI7661ESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for SI7661ESA+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 SI7661ESA+T reliable?
The price and inventory of SI7661ESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI7661ESA+T is usually 5 days.
3.What payment methods are accepted for SI7661ESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI7661ESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI7661ESA+T?
SI7661ESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI7661ESA+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 SI7661ESA+T?
For technical support, including SI7661ESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI7661ESA+T requirements.
6.How does Aetrix verify that SI7661ESA+T is sourced from the original manufacturer or authorized distributors?
All SI7661ESA+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 SI7661ESA+T meets industry standards.
7.What is the process for return or replacement of SI7661ESA+T?
All SI7661ESA+T units undergo pre-shipment inspection (PSI). If there is an issue with SI7661ESA+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 SI7661ESA+T part is unused and in its original packaging.
Return procedure for SI7661ESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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