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Analog Devices Inc./Maxim Integrated MAX688ESA+
- Part No.:
- MAX688ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX688ESA+.pdf
- Description:
- IC REG LINEAR 3.3V 1A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,650
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Product details
Overview
The MAX688ESA+ from Maxim Integrated is a precision 3.3V fixed-output, low-dropout linear regulator requiring an external PNP pass transistor; it delivers up to 1A output current with 40mV dropout at 200mA (FZT749), supports 2.7V–11.0V input range, and features active-low SHDN control with precise 1.25V turn-on threshold for battery-powered instrumentation.
For engineers reviewing the MAX688ESA+ datasheet, MAX688ESA+ pinout, MAX688ESA+ application, or MAX688ESA+ equivalent, this page provides verified technical context, real-world design meaning of specifications, validated pin functions, confirmed alternative parts with functional differences, and supply-chain support details specific to industrial and portable equipment designs.
Technical Context
The MAX688ESA+ operates as a controller IC-not a complete LDO-relying on an external high-gain PNP transistor (e.g., FZT749) for power delivery while internally regulating base drive, monitoring output voltage via PFO, and managing three-level shutdown states (on/standby/shutdown) based on SHDN voltage thresholds. Its reference and comparators remain fully operational in standby mode.
It implements base-current limiting via a resistor between BASE and BLIM pins (IBASE ≤ 0.1V / (RB + 5Ω)), enabling output current limiting without collector-sense resistors, and maintains <±2% output accuracy over temperature and load while rejecting line transients down to 2mV peak-to-peak for 3.4V–3.6V input steps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2% - ensures stable logic supply for 3.3V microcontrollers and memory without external feedback. |
| Input Voltage Range | 2.7V to 11.0V - supports single-cell Li-ion (3.0–4.2V), dual-cell alkaline (2.4–3.2V), and 5V/9V wall adapters. |
| Dropout Voltage | 40mV at 200mA (FZT749) - enables regulation down to ~3.34V input, critical for extending battery runtime in portable devices. |
| SHDN Threshold | 1.25V (on), 1.2V (standby entry), 0.2V (full shutdown) - allows precise, hysteresis-controlled power sequencing using simple resistor dividers. |
| PFO Function | Open-drain output tripping 170mV below nominal VOUT - provides early warning of output droop for system-level brownout handling. |
| Supply Current | 150µA operating, <1µA in shutdown - minimizes quiescent drain in always-on backup rails and battery-critical systems. |
| Package | 8-pin SO (SOIC) - surface-mount compatible with standard reflow profiles and automated assembly. |
Pinout & Package
MAX688ESA+ is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm body, 1.27mm pitch, JEDEC MS-012AC compliant, rated for -40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN | Positive input supply | Accepts 2.7V–11.0V unregulated input; bypass capacitor must be placed directly between IN and GND. |
| 2 SHDN | Active-low shutdown control | Three-level input: >1.25V = on, <1.2V = standby (<25µA), <0.2V = full shutdown (<1µA); open-drain PFO asserts low when SHDN <0.2V. |
| 3 PFO | Power-fail open-drain output | Signals VOUT droop ≥170mV below 3.3V; sinks current only; requires external pull-up for logic-level interface. |
| 4 GND | Circuit ground reference | Common return for IN, OUT, CC, BASE, BLIM; must be low-impedance connection to minimize noise coupling. |
| 5 OUT | Regulated output node | 3.3V fixed output delivered via external PNP transistor emitter; connects to load and output capacitor C2. |
| 6 BLIM | Base current limit sense | Sets max base drive via resistor to BASE; IBASE ≤ 0.1V/(RB + 5Ω); enables current limiting without collector sensing. |
| 7 BASE | External PNP base driver | Supplies ≥10mA base current to PNP; internal drive strength supports >1A output with β >100 transistors. |
| 8 CC | Compensation capacitor node | Connects 10nF–100nF non-polarized capacitor to GND; stabilizes loop response and suppresses startup overshoot. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Guaranteed ±2% accuracy across -40°C to +85°C and 1µA–1A load - eliminates need for external trimming in 3.3V system rails. |
| Three-level SHDN control | Enables precise, hysteresis-stabilized power sequencing: full on → low-power standby → ultra-low-IQ shutdown - ideal for wake-on-event architectures. |
| Open-drain PFO | Provides fail-safe early-warning signal at 3.13V (170mV below 3.3V) - allows host MCU to initiate graceful shutdown before brownout. |
| BASE/BLIM current limiting | Resistor-programmable base drive limits output current without degrading dropout voltage - preserves efficiency during overload or dropout conditions. |
| Low-noise operation | 105µVRMS output noise (10Hz–1MHz) and <2mV line transient response - suitable for noise-sensitive analog and RF subsystems. |
Applications
| Portable Telephones | Battery-Powered Instruments |
|---|---|
Use Scenario: Powering RF front-end, audio codec, and baseband processor in GSM/CDMA handsets with single Li-ion cell. IC Role / Device Role / Timing Role: Primary 3.3V system regulator controlling external PNP pass transistor to maintain stable rail during transmit bursts and sleep cycles. Use Value: 40mV dropout at 200mA extends usable battery voltage range by ~150mV, delaying low-battery shutdown and increasing talk time. |
Use Scenario: Supplying precision ADCs, op-amps, and microcontrollers in handheld multimeters and gas detectors. IC Role / Device Role / Timing Role: Low-noise, high-accuracy 3.3V source with PFO monitoring for self-calibration and low-voltage alerting. Use Value: <±2% output accuracy and 105µVRMS noise ensure measurement repeatability; PFO triggers recalibration before VOUT drift affects readings. |
| Memory Backup Supply | Industrial Portable Data Loggers |
Use Scenario: Providing regulated 3.3V to SRAM or FRAM during main power loss in embedded controllers. IC Role / Device Role / Timing Role: Standby-mode regulator activated by SHDN to sustain memory retention with <25µA quiescent current. Use Value: Three-level SHDN allows seamless transition from main power to backup battery without reset, preserving volatile data state. |
Use Scenario: Powering GPS modules, sensors, and LoRaWAN transceivers in field-deployed environmental monitors. IC Role / Device Role / Timing Role: Main system regulator with PFO-driven firmware logging of low-VIN events and autonomous shutdown at 3.13V. Use Value: Early PFO warning enables timestamped event logging before shutdown, improving failure diagnostics and battery life modeling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout linear regulator controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX687ESA+ | Includes automatic latched shutdown at 2.96V and ON pin instead of SHDN; PFO sources/sinks current. | Used where battery protection requires irreversible shutdown until manual reset (e.g., CMOS RAM backup). | Select MAX687ESA+ only if automatic latch-off and ON-triggered restart are required; not drop-in compatible due to different control pin function. |
| LT1528CS8#PBF | Integrated PNP pass transistor; 3.3V fixed output; 350mV dropout at 3A; no external transistor needed. | Preferred for space-constrained designs needing higher current (>1A) without discrete transistor layout and thermal management. | Choose LT1528CS8#PBF when board area, thermal design simplicity, or >1A continuous output outweighs flexibility of external transistor selection. |
Compared with MAX687ESA+, the MAX688ESA+ offers programmable shutdown timing and open-drain PFO for flexible system integration, while the LT1528CS8#PBF trades external transistor flexibility for integrated simplicity and higher current capability - making MAX688ESA+ optimal for mid-power, thermally managed, externally optimized LDO designs.
Availability
MAX688ESA+ is available at Aetrix Electronics and suitable for portable telephones, battery-powered instruments, memory backup supplies, and industrial data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX688ESA+ 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, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX687/MAX688/MAX689 family was designed as precision external-transistor LDO controllers targeting battery-critical portable equipment where adjustable dropout, programmable shutdown, and PFO monitoring are essential for system reliability.
FAQ
What is the primary function of the MAX688ESA+ in a power supply design?
The MAX688ESA+ serves as a precision 3.3V low-dropout linear regulator controller that drives an external PNP pass transistor. It does not include the power transistor itself but provides regulated base drive, output voltage monitoring via PFO, and three-level SHDN control. In practice, the MAX688ESA+ enables highly efficient, thermally flexible, and current-scalable 3.3V regulation - especially valuable when optimizing for low dropout, low quiescent current, or custom thermal management using discrete transistors like the FZT749.
Does the MAX688ESA+ include an integrated pass transistor?
No, the MAX688ESA+ does not include an integrated pass transistor. It is a controller IC requiring an external high-gain PNP transistor (e.g., FZT749, 2N2907A, or TIP42) connected between IN and OUT. This architecture allows designers to select transistors optimized for current, thermal performance, and package size - unlike monolithic LDOs. The MAX688ESA+ provides ≥10mA base drive and implements base-current limiting via the BLIM pin to manage output current safely.
What is the significance of the SHDN pin's three-level voltage thresholds on the MAX688ESA+?
The SHDN pin on the MAX688ESA+ has three defined thresholds: >1.25V for normal operation, <1.2V for standby mode (<25µA supply current), and <0.2V for full shutdown (<1µA). This enables precise, hysteresis-stabilized power sequencing - for example, using a resistor divider from VIN to trigger standby before full shutdown, allowing system firmware to save state or disable peripherals. Unlike simple on/off control, this staged response prevents chatter and supports energy-aware wake-up architectures in battery-powered devices using the MAX688ESA+.
How does the PFO output function on the MAX688ESA+?
The PFO (Power-Fail Output) on the MAX688ESA+ is an open-drain output that pulls low when the regulated 3.3V output drops ≥170mV below nominal (i.e., ≤3.13V). It remains low during shutdown regardless of VOUT. Because it's open-drain, PFO requires an external pull-up resistor to interface with logic inputs. Its purpose is to provide early warning of output droop - enabling host microcontrollers to initiate controlled shutdown, data save, or fault logging before brownout occurs - a key reliability feature in systems powered by aging or low-charge batteries using the MAX688ESA+.
What package type and temperature range does the MAX688ESA+ use?
The MAX688ESA+ uses an 8-pin SO (Small Outline) package, measuring 3.9mm × 4.9mm with 1.27mm lead pitch, compliant with JEDEC MS-012AC. It is rated for operation from -40°C to +85°C, making it suitable for industrial and extended-temperature portable applications. The "E" suffix denotes the extended temperature grade, and "SA" specifies the SO package - distinct from the "CPA" (plastic DIP) or "CUA" (µMAX) variants. This package supports standard surface-mount assembly and offers better thermal performance than µMAX for moderate-power designs using the MAX688ESA+.
MAX688ESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 11V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.04V @ 200mA (Typ)
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 25 µA
- Current - Supply (Max):
- 250 µA
- PSRR:
- -
- Control Features:
- Current Limit, Enable, Power Fail
- Protection Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX688ESA+ FAQ
1.How can I place an order for MAX688ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX688ESA+ 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 MAX688ESA+ reliable?
The price and inventory of MAX688ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX688ESA+ is usually 5 days.
3.What payment methods are accepted for MAX688ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX688ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX688ESA+?
MAX688ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX688ESA+ 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 MAX688ESA+?
For technical support, including MAX688ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX688ESA+ requirements.
6.How does Aetrix verify that MAX688ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX688ESA+ 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 MAX688ESA+ meets industry standards.
7.What is the process for return or replacement of MAX688ESA+?
All MAX688ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX688ESA+, 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 MAX688ESA+ part is unused and in its original packaging.
Return procedure for MAX688ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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