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Analog Devices Inc. LT1638CN8#PBF
- Part No.:
- LT1638CN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1638CN8#PBF.pdf
- Description:
- IC OPAMP GP 2 CIRCUIT 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,511
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Product details
Overview
LT1638CN8#PBF from Analog Devices (formerly Linear Technology) is a dual rail-to-rail input/output operational amplifier in 8-lead PDIP package, featuring Over-The-Top® operation with inputs up to 44V above V–, 1.2MHz gain bandwidth, 0.4V/µs slew rate, and 170µA per amplifier quiescent current. It operates from 2.5V to 44V total supply and is reverse-battery protected to 18V, enabling use in battery monitoring and high-side sensing circuits.
For engineers reviewing the LT1638CN8#PBF datasheet, LT1638CN8#PBF pinout, LT1638CN8#PBF application, or LT1638CN8#PBF equivalent, key selection criteria include its rail-to-rail I/O capability across wide supply range, guaranteed operation with inputs above V+, ±25mA output drive, and specified performance over –40°C to +85°C for industrial embedded systems.
Technical Context
The LT1638CN8#PBF integrates dual independent amplifiers with separate NPN and PNP input stages, enabling seamless transition across the full common-mode range-including operation with either input above V+. Its Over-The-Top architecture allows direct sensing of voltages up to 44V referenced to V–, independent of supply voltage.
It features internal phase reversal protection, 1kΩ series input resistors for negative overvoltage tolerance, and unity-gain stability with optional compensation for capacitive loads up to 1000pF. The device draws only 170µA per amplifier at 25°C and maintains rail-to-rail swing under 10mA load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth Product | 1.2MHz typical - enables stable closed-loop operation up to ~1MHz with gain ≥1. |
| Slew Rate | 0.4V/µs typical - supports 100kHz full-power sine wave at 4Vpp without distortion. |
| Supply Current per Amp | 170µA typical - allows micropower operation in battery-powered sensor nodes. |
| Input Voltage Range | –0.4V to 44V (vs V–) - permits direct high-side current sensing on 44V rails without level-shifting. |
| Output Drive | ±25mA min - drives 2kΩ loads while maintaining rail-to-rail swing at 5V supply. |
| CMRR | 98dB typical - rejects common-mode noise in precision instrumentation front-ends. |
| Input Offset Voltage | 200µV max (0°C to 70°C) - ensures <1mV error in 5V-scale single-supply signal conditioning. |
Pinout & Package
LT1638CN8#PBF is housed in an 8-lead plastic DIP (N8) package with through-hole mounting, 0.300" wide body, and standard 0.1" lead pitch. Pin 1 is marked by a notch or dot; thermal resistance θJA = 150°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: OUT A | Amplifier A output | Delivers rail-to-rail voltage with ±25mA drive capability; connects directly to load or feedback network. |
| 2: –IN A | Inverting input A | Accepts signals from –0.4V to 44V relative to V–; includes 1kΩ series resistor for negative overvoltage protection. |
| 3: +IN A | Non-inverting input A | Same voltage range as –IN A; enables high-side sensing when tied to V+ or external high-voltage node. |
| 4: V– | Negative supply | Reference for all inputs and outputs; underside metal pad (in DFN variants) internally connected to V–. |
| 5: V+ | Positive supply | Accepts 2.5V to 44V total supply; bypass with 0.1µF capacitor within 1 inch for stability. |
| 6: +IN B | Non-inverting input B | Independent second channel input; identical Over-The-Top and rail-to-rail specifications as Channel A. |
| 7: –IN B | Inverting input B | Dual-channel symmetry enables matched differential or dual-sensing configurations. |
| 8: OUT B | Amplifier B output | Fully independent output; shares same drive strength and swing limits as OUT A. |
Key Features
| Feature | Design Value |
|---|---|
| Over-The-Top® Input Operation | Enables direct connection of inputs to nodes up to 44V above V–, eliminating need for external level shifters in high-side sensing. |
| Rail-to-Rail Input and Output | Supports full dynamic range utilization from V– to V+ on both inputs and outputs, maximizing SNR in low-voltage systems. |
| Reverse Battery Protection | Draws <1nA supply current during –18V reverse supply, preventing damage and system latch-up in automotive applications. |
| No Phase Reversal | Internal circuitry prevents output inversion when inputs fall below V–, ensuring predictable behavior in fault conditions. |
| Unity-Gain Stable with Compensation | Drives ≥200pF capacitively loaded outputs natively; optional RC network extends stability to 1000pF for LCD or cable drivers. |
Applications
| Battery Monitoring | High-Side Current Sensing |
|---|---|
Use Scenario: Real-time monitoring of 12V–48V battery packs in portable medical devices or UPS systems. IC Role / Device Role / Timing Role: Amplifier A measures voltage across shunt resistor on positive rail; amplifier B buffers reference or processes secondary parameter. Use Value: Direct Over-The-Top input capability eliminates isolation components, reducing BOM cost and PCB area by >30% versus isolated solutions. | Use Scenario: Precision current measurement in industrial motor controllers with 24V–44V DC bus. IC Role / Device Role / Timing Role: Configured as difference amplifier with matched resistors to sense voltage drop across high-side shunt. Use Value: 98dB CMRR and 200µV offset ensure <0.5% full-scale error at 10A/10mΩ, meeting IEC 61000-4-5 surge immunity requirements. |
| Micropower Active Filters | 4mA–20mA Transmitter |
Use Scenario: Low-drift 2nd-order Sallen-Key filter in wireless sensor nodes powered by coin-cell batteries. IC Role / Device Role / Timing Role: Dual amplifier implements filter topology with one section providing gain and the other buffering output. Use Value: 170µA per amplifier enables >5-year battery life at 1Hz sampling, while rail-to-rail I/O preserves dynamic range at 3V supply. | Use Scenario: Two-wire loop-powered transmitter converting temperature sensor output to 4–20mA signal. IC Role / Device Role / Timing Role: Amplifier A conditions sensor signal; amplifier B serves as current-output stage with external transistor. Use Value: Reverse battery protection and –0.4V input range allow safe operation during field wiring errors, reducing commissioning failures by >90%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8605ARZ-REEL7 | Single-channel, 10MHz GBW, 5V max supply, no Over-The-Top capability | Limited to ≤5V systems; unsuitable for 44V sensing or reverse-battery environments | Select only for low-voltage, high-speed signal conditioning where rail extension is unnecessary. |
| OPA2333AIDR | Dual-channel, zero-drift architecture, 350kHz GBW, 5.5V max supply, no Over-The-Top | Superior DC accuracy (0.02µV/°C drift) but incompatible with >5.5V supplies or high-side sensing | Prefer for precision DC-coupled instrumentation at ≤5.5V; avoid for battery monitoring or industrial power rails. |
Compared with AD8605ARZ-REEL7 and OPA2333AIDR, LT1638CN8#PBF uniquely supports 2.5V–44V operation with Over-The-Top inputs, making it irreplaceable in high-voltage micropower sensing-while alternatives trade voltage range for speed or DC precision in low-voltage domains.
Availability
LT1638CN8#PBF is available at Aetrix Electronics and suitable for battery monitoring, high-side current sensing, and micropower active filters requiring stable component supply across industrial temperature ranges.
Supply support for LT1638CN8#PBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.
The LT1638 product line was designed specifically for micropower, high-voltage rail-to-rail signal conditioning in harsh environments-targeting battery-powered instrumentation, automotive subsystems, and industrial process control.
FAQ
What is the maximum input voltage range supported by LT1638CN8#PBF relative to V–?
The LT1638CN8#PBF supports an input voltage range of –0.4V to 44V relative to V–, enabling direct connection to high-side nodes up to 44V above the negative rail. This Over-The-Top® capability is guaranteed across the full –40°C to +85°C operating temperature range and does not depend on V+ level. The LT1638CN8#PBF achieves this via dual NPN/PNP input stages and internal Schottky clamping, allowing robust operation in battery monitoring and industrial power rail applications.
Does LT1638CN8#PBF require external compensation for driving capacitive loads?
The LT1638CN8#PBF is unity-gain stable and can drive up to 200pF capacitively loaded outputs without external compensation. For loads exceeding 200pF-such as LCD panels or long cables-a 0.22µF capacitor in series with a 150Ω resistor between output and ground provides optional compensation, extending stable operation to 1000pF. This RC network is documented in the LT1638/LT1639 datasheet Figure 12 and applies identically to the LT1638CN8#PBF in PDIP packaging.
What is the reverse battery protection rating for LT1638CN8#PBF?
The LT1638CN8#PBF provides reverse battery protection up to –18V on the V+ pin, drawing less than 1nA supply current under that condition. This feature is intrinsic to the internal architecture and requires no external components. It ensures system safety during incorrect battery installation in portable equipment and automotive accessories, and is fully characterized across the –40°C to +85°C temperature range specified for the LT1638CN8#PBF.
Can LT1638CN8#PBF operate from a single 3V supply while maintaining rail-to-rail output swing?
Yes, the LT1638CN8#PBF operates from a single 3V supply (V+ = 3V, V– = 0V) and delivers rail-to-rail output swing: VOL ≤ 8mV and VOH ≥ 2.94V at no load, and maintains ≥2.25V high swing and ≤450mV low swing at 5mA sink/source. These values are specified in the Electrical Characteristics table for LT1638C grade and apply directly to the LT1638CN8#PBF, enabling full dynamic range utilization in ultra-low-power 3V sensor interfaces.
Is LT1638CN8#PBF pin-compatible with other packages in the LT1638 family?
Yes, the LT1638CN8#PBF (8-lead PDIP) shares identical pinout with the LT1638CS8#PBF (SO-8) and LT1638CMS8#PBF (MSOP-8), as confirmed by the Pin Configuration diagrams in the LT1638/LT1639 datasheet. All three packages route OUT A, –IN A, +IN A, V–, V+, +IN B, –IN B, and OUT B to pins 1–8 respectively. This allows direct PCB footprint interchangeability between through-hole and surface-mount variants without layout changes.
LT1638CN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 2
- 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:
- 250 µV
- Current - Supply:
- 205µA (x2 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1638CN8#PBF FAQ
1.How can I place an order for LT1638CN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1638CN8#PBF 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 LT1638CN8#PBF reliable?
The price and inventory of LT1638CN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1638CN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1638CN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1638CN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1638CN8#PBF?
LT1638CN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1638CN8#PBF 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 LT1638CN8#PBF?
For technical support, including LT1638CN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1638CN8#PBF requirements.
6.How does Aetrix verify that LT1638CN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1638CN8#PBF 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 LT1638CN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1638CN8#PBF?
All LT1638CN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1638CN8#PBF, 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 LT1638CN8#PBF part is unused and in its original packaging.
Return procedure for LT1638CN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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