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Analog Devices Inc. LT1639IS
- Part No.:
- LT1639IS
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1639IS.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,545
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Product details
Overview
LT1639IS from Analog Devices (formerly Linear Technology) is a quad rail-to-rail input and output operational amplifier with Over-The-Top® capability, enabling operation with inputs up to 44V above the negative supply or above V+. It delivers 1.2MHz gain bandwidth, 0.4V/µs slew rate, and 25mA output drive per amplifier on supplies from 2.5V to 44V, drawing only 170µA per amplifier - ideal for battery-powered sensor conditioning and supply current sensing.
For engineers reviewing the LT1639IS datasheet, LT1639IS pinout, LT1639IS application, or LT1639IS equivalent, key selection criteria include its 44V input common-mode range beyond V+, reverse-battery protection to 18V, rail-to-rail I/O swing, low quiescent current, and guaranteed performance over –40°C to +85°C in the 14-lead SO package.
Technical Context
The LT1639IS uses dual-input-stage architecture (NPN and PNP) to achieve Over-The-Top operation: inputs can exceed V+ by up to ~0.3V while maintaining functionality, with phase reversal protection and internal 1kΩ series input resistors. Its input stage handles ±44V differential and common-mode voltage independent of supply.
Internally compensated for stability with ≥200pF capacitive loads, it supports optional RC compensation (0.22µF + 150Ω) for up to 1000pF. Output drives ±25mA minimum while sustaining rail-to-rail swing - 20mV from V+ and 3mV from V– at no load - and features reverse supply current <1nA under –18V conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth Product | 1.2MHz typical - enables stable unity-gain operation and accurate signal amplification up to audio frequencies. |
| Slew Rate | 0.4V/µs typical - supports clean reproduction of 10kHz full-scale square waves without distortion. |
| Supply Current per Amplifier | 170µA typical - allows four-channel precision amplification in micropower systems (<700µA total). |
| Input Common-Mode Range | –0.4V to 44V - permits direct sensing of high-side voltages (e.g., 44V bus) with single-supply operation. |
| Output Drive Capability | ±25mA minimum - drives 2kΩ loads fully rail-to-rail while maintaining linearity and settling time. |
| CMRR | 98dB typical - rejects noise from shared power rails in multi-amplifier sensor front-ends. |
| Reverse Battery Protection | Withstands –18V supply - eliminates need for external blocking diodes in automotive or portable battery systems. |
Pinout & Package
The LT1639IS is supplied in a 14-lead plastic SO (small outline) package with exposed pad not connected internally; thermal resistance θJA = 160°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT A) | Amplifier A output | Drives external load; rail-to-rail swing (20mV from V+, 3mV from V–) at no load. |
| 2 (–IN A) | Inverting input A | Differential input node; protected by 1kΩ series resistor and phase reversal circuitry. |
| 3 (+IN A) | Non-inverting input A | Differential input node; supports Over-The-Top operation up to 44V above V–. |
| 4 (V–) | Negative supply | Reference for all amplifiers; underside metal pad (SO package) is not internally connected. |
| 5 (+IN C) | Non-inverting input C | Independent input for third amplifier; identical Over-The-Top and ESD protection as pins 2–3. |
| 6 (–IN C) | Inverting input C | Independent input for third amplifier; shares same input stage architecture and bias behavior. |
| 7 (OUT C) | Amplifier C output | Matches OUT A electrical specs; capable of sourcing/sinking ≥25mA. |
| 8 (V+) | Positive supply | Bypass with 0.1µF capacitor within 25mm; rise time must be ≤1V/µs for supplies ≥10V. |
| 9 (OUT D) | Amplifier D output | Fourth output channel; fully independent; same drive strength and rail-to-rail capability. |
| 10 (–IN D) | Inverting input D | Fourth amplifier inverting input; supports common-mode range up to 44V above V–. |
| 11 (+IN D) | Non-inverting input D | Fourth amplifier non-inverting input; compatible with high-voltage sensor interfaces. |
| 12 (V–) | Negative supply (shared) | Common return for all four amplifiers; reverse-battery protected to –18V. |
| 13 (+IN B) | Non-inverting input B | Second amplifier non-inverting input; identical Over-The-Top specification and input impedance. |
| 14 (–IN B) | Inverting input B | Second amplifier inverting input; matches pin 2 in bias current profile and protection. |
Key Features
| Feature | Design Value |
|---|---|
| Over-The-Top® Input Operation | Inputs function reliably at voltages up to 44V above V– or >V+, enabling direct high-side current/voltage monitoring without level-shifting. |
| Rail-to-Rail Input and Output | Full dynamic range utilization across 2.5V–44V supplies - maximizes ADC resolution in low-voltage battery systems and high-voltage industrial sensors. |
| Reverse Battery Protection | Draws <1nA at –18V supply - eliminates external protection diodes and associated voltage drop/power loss in portable equipment. |
| Low Power Consumption | 170µA per amplifier at 25°C - supports always-on sensor nodes with multi-year battery life using four independent channels. |
| Phase Reversal Protection | Prevents false output polarity when inputs fall below V– - critical for fault-tolerant safety monitoring circuits. |
Applications
| Battery Monitoring | High-Voltage Sensor Conditioning |
|---|---|
Use Scenario: Real-time monitoring of 12V–48V lead-acid or Li-ion battery packs in UPS or portable medical devices. IC Role / Device Role / Timing Role: Quad amplifier configured as four independent differential sense amplifiers measuring cell voltage, pack current, temperature, and charge status. Use Value: Over-The-Top inputs directly interface to battery terminals without level shifters; rail-to-rail output drives low-power ADCs with full-scale accuracy. | Use Scenario: Signal conditioning for pressure, flow, or position sensors powered from 24V industrial buses. IC Role / Device Role / Timing Role: First-stage amplifier for 4–20mA transmitter front-end, accepting sensor bridge outputs referenced to 24V rail. Use Value: 44V input common-mode range allows direct connection to 24V-sourced bridges; low 170µA quiescent current minimizes self-heating error. |
| Supply Current Sensing | Micropower Active Filters |
Use Scenario: Accurate measurement of system supply current in IoT edge nodes powered by coin cells or energy harvesters. IC Role / Device Role / Timing Role: High-side current sense amplifier using 0.1Ω shunt, with output scaled for µC ADC input. Use Value: Inputs operate >V+ (e.g., 3.3V supply + 0.1V drop), eliminating need for expensive isolated amplifiers or complex level translation. | Use Scenario: Low-noise, low-drift anti-aliasing or tone-shaping filters in portable instrumentation with strict power budgets. IC Role / Device Role / Timing Role: Quad op-amp implementing 2-pole Sallen-Key low-pass filter with gain and buffering stages. Use Value: 1.2MHz GBW and 0.4V/µs slew rate support 10kHz cutoff with <0.1% THD+N; 170µA/channel enables multi-filter designs on single coin cell. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1639CS | Same die, identical electrical specs, but rated for commercial temperature range (0°C to 70°C) instead of industrial (–40°C to 85°C). | Not suitable for extended ambient environments like automotive cabins or outdoor industrial enclosures. | Select LT1639IS when operating reliability across –40°C to +85°C is required; LT1639CS is lower-cost for benign environments. |
| AD8604ARZ | Lower supply current (42µA vs 170µA), lower GBW (8MHz vs 1.2MHz), no Over-The-Top capability - max input CMR = V– to V+ – 0.1V. | Cannot replace LT1639IS in high-side sensing or reverse-battery applications; requires level-shifting for >V+ signals. | Choose AD8604ARZ only for ultra-low-power, low-voltage (≤5.5V), low-frequency (<100kHz) applications where Over-The-Top is unnecessary. |
Compared with LT1639CS and AD8604ARZ, the LT1639IS uniquely combines industrial-temperature rating, 44V Over-The-Top input operation, and reverse-battery protection - making it irreplaceable in ruggedized battery management and industrial sensor signal chains where voltage excursions and ambient extremes are routine.
Availability
LT1639IS is available at Aetrix Electronics and suitable for battery monitoring, high-voltage sensor conditioning, and supply current sensing requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1639IS 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
Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LT1639IS belongs to ADI's legacy Linear Technology precision op amp product line, engineered specifically for micropower, high-voltage input, and rail-to-rail performance in harsh-environment instrumentation and power management systems.
FAQ
What is the maximum input common-mode voltage for the LT1639IS?
The LT1639IS supports an input common-mode voltage range from –0.4V to 44V relative to V–, independent of supply voltage. This means either or both inputs can operate up to 44V above V– - including voltages exceeding V+ - enabling true Over-The-Top® functionality essential for high-side sensing. The LT1639IS maintains specified performance across this full range at temperatures from –40°C to +85°C.
Does the LT1639IS require external protection when used in reverse-battery configurations?
No, the LT1639IS includes built-in reverse battery protection and draws less than 1nA when subjected to –18V supply. This eliminates the need for external blocking diodes or protection circuits in automotive, portable, or backup power applications. The LT1639IS remains functional and undamaged under reverse supply conditions, preserving system reliability without added BOM cost or board space.
Can the LT1639IS drive capacitive loads without oscillation?
Yes, the LT1639IS is internally compensated for stable operation with ≥200pF capacitive loads. For larger loads up to 1000pF, optional external compensation - a 0.22µF capacitor in series with a 150Ω resistor from output to ground - ensures stability across all output currents and supply voltages. This capability makes the LT1639IS suitable for driving long traces, cables, or ADC input capacitance without additional isolation components.
What is the guaranteed output drive strength of the LT1639IS at 5V supply?
At VS = 5V (V+ = 5V, V– = 0V), the LT1639IS guarantees ±25mA output current per amplifier while maintaining rail-to-rail swing (within 20mV of V+, 3mV of V– at no load). Short-circuit current is specified at 15–25mA depending on test condition. This drive strength supports direct interfacing to 200Ω loads, LED drivers, or multiple logic inputs without external buffers - confirmed across the full –40°C to +85°C industrial temperature range.
How does the LT1639IS handle input voltages below the negative supply rail?
The LT1639IS incorporates internal 1kΩ series resistors and clamping diodes from each input to V–, protecting against excursions up to 2V below V–. For deeper excursions (e.g., –10V), an external series resistor (e.g., 10kΩ) is recommended. Crucially, the input stage includes phase reversal protection - preventing erroneous output polarity inversion when inputs go below V– - a key reliability feature for fault-monitoring circuits using the LT1639IS.
LT1639IS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- LT®
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 4
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.4V/µs
- Gain Bandwidth Product:
- 1.2 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 20 nA
- Voltage - Input Offset:
- 350 µV
- Current - Supply:
- 205µA (x4 Channels)
- Current - Output / Channel:
- 40 mA
- Voltage - Supply Span (Min):
- 2.5 V
- Voltage - Supply Span (Max):
- 44 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
LT1639IS FAQ
1.How can I place an order for LT1639IS through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1639IS 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 LT1639IS reliable?
The price and inventory of LT1639IS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1639IS is usually 5 days.
3.What payment methods are accepted for LT1639IS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1639IS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1639IS?
LT1639IS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1639IS 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 LT1639IS?
For technical support, including LT1639IS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1639IS requirements.
6.How does Aetrix verify that LT1639IS is sourced from the original manufacturer or authorized distributors?
All LT1639IS 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 LT1639IS meets industry standards.
7.What is the process for return or replacement of LT1639IS?
All LT1639IS units undergo pre-shipment inspection (PSI). If there is an issue with LT1639IS, 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 LT1639IS part is unused and in its original packaging.
Return procedure for LT1639IS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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