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Analog Devices Inc./Maxim Integrated MAX689ESA
- Part No.:
- MAX689ESA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX689ESA.pdf
- Description:
- IC REG LINEAR LDO
- Quantity:
- Payment:
- Shipping:
Inventory:3,222
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Product details
Overview
MAX689ESA from Maxim Integrated is a precision 3.0V fixed-output, low-dropout linear regulator requiring an external PNP pass transistor; delivers up to 1A output current with ≥10mA base drive, features open-drain power-fail output (PFO), active-low shutdown control (SHDN), and operates from 2.7V to 11.0V input; used in battery-powered portable telephones and memory backup supplies.
For engineers reviewing the MAX689ESA datasheet, MAX689ESA pinout, MAX689ESA application, or MAX689ESA equivalent, this page provides verified technical context, real-world dropout behavior at 200mA/40mV and 650mA/100mV, SHDN threshold hysteresis (70mV), ±2% output accuracy, and confirmed SO-8 package mapping - all validated against Maxim's official 1994 datasheet.
Technical Context
The MAX689ESA implements precision voltage regulation using an external PNP transistor controlled via BASE/BLIM current limiting; its internal reference and comparators remain functional down to 2.7V input, enabling reliable low-voltage operation in battery discharge scenarios.
It employs a three-level SHDN interface: >1.25V for normal operation, <1.2V for standby (<25µA supply current), and <0.2V for full shutdown (<1µA); PFO trips at 170mV below nominal VOUT (2.83V) with 7mV hysteresis and functions as an open-drain output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.0V ±2% over temperature and load - ensures stable logic supply for 3V microcontrollers and SRAM. |
| Dropout Voltage | 40mV at 200mA (FZT749), 100mV at 650mA - enables regulation even with weak or aging batteries. |
| Input Voltage Range | 2.7V to 11.0V - supports single-cell Li-ion (3.0–4.2V), dual-cell NiMH (2.4–3.0V), and higher-voltage backup rails. |
| SHDN Thresholds | VON = 1.25V (±2%), VSTBY = 1.2V, VSD = 0.2V - allows precise, hysteresis-stabilized power sequencing. |
| PFO Trip Point | 2.83V (3.0V − 170mV) with 7mV hysteresis - provides early warning before output falls out of spec. |
| Supply Current | 150µA operating, <1µA in shutdown - minimizes quiescent drain in always-on battery systems. |
| Package | 8-pin SO (Small Outline) - surface-mount compatible with standard PCB assembly and thermal relief design. |
Pinout & Package
MAX689ESA is housed in an 8-pin SO (Small Outline) package per Maxim's ordering table, rated for −40°C to +85°C operation. Pin numbering follows standard SO top-view orientation with Pin 1 at bottom-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN | Positive input supply | Accepts 2.7V–11.0V; bypass capacitor required between IN and GND for stability. |
| 2 SHDN | Active-low shutdown control | Three-level input: >1.25V = on, <1.2V = standby, <0.2V = full shutdown; open-drain PFO asserts low when SHDN < 0.2V. |
| 3 PFO | Power-fail open-drain output | Asserts low when VOUT ≤ 2.83V; sinks current only; requires external pull-up for logic-level signaling. |
| 4 GND | Circuit ground reference | Common return for IN, OUT, CC, BASE, BLIM; must be low-impedance connection to minimize noise. |
| 5 OUT | Regulated 3.0V output | Drives external load via PNP emitter follower; output capacitor (C2) minimum 10µF, ESR ≤ 1% of RL. |
| 6 BLIM | Base current limit sense | Resistor (RB) between BASE and BLIM sets max base drive: IBASE ≤ 0.1V / (RB + 5Ω); limits output current and dropout dissipation. |
| 7 BASE | PNP transistor base drive | Sources ≥10mA to external PNP (e.g., FZT749); connects directly to PNP base; shorted to BLIM for max drive. |
| 8 CC | Compensation node | Connects 10nF–100nF non-polarized capacitor to GND; stabilizes loop response and suppresses startup overshoot. |
Key Features
| Feature | Design Value |
|---|---|
| External PNP drive | ≥10mA base current supports >1A output with high-hFE transistors (β > 100), avoiding integrated pass device limitations. |
| Low dropout performance | 40mV at 200mA enables regulation from 3.04V input - critical for preserving battery runtime in portable instruments. |
| Three-state SHDN control | Enables precise power sequencing: full-on → low-IQ standby → ultra-low-IQ shutdown, reducing system leakage by >150×. |
| Open-drain PFO | Provides fail-safe monitoring of 3.0V rail with 170mV trip margin and 7mV hysteresis - prevents false triggers from line transients. |
| High output accuracy | ±2% over −40°C to +85°C ensures compatibility with 3.0V logic families (e.g., 3V SPI peripherals, low-voltage RAM). |
Applications
| Portable Telephones | Battery-Powered Memory Backup |
|---|---|
|
Use Scenario: Powering RF front-end and baseband ICs in GSM/CDMA handsets during battery discharge from 4.2V to 3.0V. IC Role / Device Role / Timing Role: Primary 3.0V LDO regulator controlling external PNP pass transistor to maintain stable supply despite falling battery voltage. Use Value: 40mV dropout at 200mA extends usable battery life by delaying brownout shutdown until battery reaches ~3.04V. |
Use Scenario: Maintaining CMOS SRAM or real-time clock (RTC) power during main supply failure or battery swap. IC Role / Device Role / Timing Role: Standby-mode regulator with SHDN held high and PFO monitoring VOUT to trigger backup switchover before data loss. Use Value: <1µA shutdown current prevents deep discharge; PFO trip at 2.83V gives 170mV warning margin before SRAM retention fails. |
| Portable Instruments | High-Efficiency Linear Regulator |
|
Use Scenario: Supplying analog front-end (AFE) and microcontroller in handheld multimeters or gas detectors powered by two AA cells. IC Role / Device Role / Timing Role: Precision 3.0V reference-grade regulator with <2mV line transient response, minimizing measurement error during battery voltage sag. Use Value: ±2% output accuracy and <2mV line regulation ensure ADC reference stability across 2.7–3.6V input range. |
Use Scenario: Replacing inefficient 78L30 or LM317-based designs where low dropout and external thermal management are required. IC Role / Device Role / Timing Role: Controller IC for discrete PNP pass stage, decoupling regulation accuracy from transistor VCE(sat) and enabling heatsink optimization. Use Value: External transistor selection (e.g., FZT749 or TIP42) allows scalable current handling (1A–4A) without changing controller IC. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX688ESA | Identical SO-8 package and pinout, but 3.3V output and same SHDN/PFO functionality. | Used where system requires 3.3V logic supply instead of 3.0V; not interchangeable without board-level voltage revision. | Select MAX688ESA only if target load is 3.3V-tolerant; verify PFO trip point shifts to 3.13V (3.3V − 170mV). |
| LT1528CS8#PBF | Integrated PNP pass device, 3.3V fixed output, 350mV dropout at 3A, no external transistor needed. | Reduces BOM count and layout complexity but lacks MAX689ESA's <1µA shutdown current and 3.0V option. | Choose LT1528CS8#PBF for simpler 3.3V designs needing >1A; use MAX689ESA when 3.0V, ultra-low IQ, or thermal separation is critical. |
Compared with MAX688ESA, MAX689ESA provides 3.0V output essential for legacy 3V logic and memory; versus LT1528CS8#PBF, it trades integration for lower shutdown current, external thermal control, and precise 3.0V regulation - making it optimal for long-life battery systems.
Availability
MAX689ESA is available at Aetrix Electronics and suitable for portable telephones, battery-powered memory backup systems, and portable instrumentation requiring stable component supply across industrial temperature ranges.
Supply support for MAX689ESA 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, interface, and sensing applications.
The MAX687/MAX688/MAX689 family was designed as precision external-PNP LDO controllers for battery-critical systems demanding ultra-low shutdown current, accurate voltage thresholds, and flexible thermal management - targeting portable and backup power markets.
FAQ
What is the output voltage tolerance of the MAX689ESA over temperature and load?
The MAX689ESA delivers a fixed 3.0V output with guaranteed accuracy of ±2% across the full −40°C to +85°C operating range and under all specified load conditions. This specification is confirmed in the Electrical Characteristics table of Maxim's datasheet, where min/max values are 2.9V/3.1V at 3.5V ≤ VIN ≤ 11.0V and 1µA ≤ IBASE ≤ 10mA. The MAX689ESA maintains this tolerance without external trimming or calibration.
Does the MAX689ESA include an internal pass transistor, or does it require an external one?
The MAX689ESA does not include an internal pass transistor; it is a controller IC that requires an external PNP transistor (e.g., FZT749 or 2N2907A) connected to the BASE and OUT pins. Its architecture separates regulation intelligence from power handling, allowing thermal optimization and current scalability beyond monolithic LDO limits - a core design feature confirmed in the General Description and Typical Operating Circuit sections of the datasheet.
What is the function of the BLIM pin on the MAX689ESA, and how is it used?
The BLIM pin on the MAX689ESA serves as the base-current limit sense node. A resistor (RB) connected between BASE and BLIM sets the maximum base drive to the external PNP transistor using the formula IBASE ≤ 0.1V / (RB + 5Ω). For example, RB = 12Ω limits base current to ~6mA. This feature prevents excessive quiescent current during dropout and provides output current limiting without adding collector-side sensing - directly documented in the Pin Description and Detailed Description sections.
How does the SHDN pin operate across voltage thresholds on the MAX689ESA?
The SHDN pin on the MAX689ESA operates in three distinct states: >1.25V (±2%) enables normal operation; <1.2V places the device in standby mode (<25µA supply current); and <0.2V forces full shutdown (<1µA). A 70mV hysteresis between on and standby thresholds prevents chatter. When SHDN falls below 0.2V, PFO is forced low - all behavior is explicitly defined in the Electrical Characteristics table and Pin Description section of the MAX689ESA datasheet.
Can the MAX689ESA be used with input voltages below 3.0V, and what is the minimum functional input?
Yes, the MAX689ESA can operate with input voltages as low as 2.7V, per its absolute maximum ratings and Electrical Characteristics table. However, regulation is only maintained while VIN exceeds VOUT plus dropout voltage - e.g., at 200mA load, VIN must stay ≥3.04V (3.0V + 40mV) to sustain 3.0V output. Below that, the output follows VIN minus VCE(sat) of the external PNP. This behavior is clarified in Note 1 of the datasheet and confirmed in Figure 4's dropout vs. load curves.
MAX689ESA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 11V
- Voltage - Output (Min/Fixed):
- 3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 250 µA
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- Current Limit, Enable, Power Fail
- Protection Features:
- Over Current
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX689ESA FAQ
1.How can I place an order for MAX689ESA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX689ESA 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 MAX689ESA reliable?
The price and inventory of MAX689ESA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX689ESA is usually 5 days.
3.What payment methods are accepted for MAX689ESA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX689ESA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX689ESA?
MAX689ESA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX689ESA 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 MAX689ESA?
For technical support, including MAX689ESA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX689ESA requirements.
6.How does Aetrix verify that MAX689ESA is sourced from the original manufacturer or authorized distributors?
All MAX689ESA 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 MAX689ESA meets industry standards.
7.What is the process for return or replacement of MAX689ESA?
All MAX689ESA units undergo pre-shipment inspection (PSI). If there is an issue with MAX689ESA, 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 MAX689ESA part is unused and in its original packaging.
Return procedure for MAX689ESA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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