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Texas Instruments OPA445AP
- Part No.:
- OPA445AP
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
OPA445AP.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:508
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Product details
Overview
OPA445AP from Texas Instruments is a high-voltage, FET-input operational amplifier in an 8-pin PDIP package, delivering ±15mA output current, 15V/µs slew rate, and operation from ±10V to ±45V supplies. It serves as a precision high-voltage signal conditioner in test equipment and piezo drivers where wide common-mode swing and low input bias current (10pA) are critical.
For engineers reviewing the OPA445AP datasheet, OPA445AP pinout, OPA445AP application, or OPA445AP equivalent, key selection criteria include its ±45V max supply rating, TO-99/DIP/SO-8 pin-compatible footprint, thermal performance in plastic DIP (θJA = 100°C/W), and verified use in voltage-to-current converters and programmable high-voltage sources.
Technical Context
The OPA445AP uses JFET input stage architecture enabling ultra-low input bias current (±10pA typ) and high input impedance (1013 Ω differential). Its laser-trimmed input circuitry achieves ±1.5mV max input offset voltage over −25°C to +85°C, supporting precision DC-coupled amplification.
It features internal offset trim pins (1 and 5), supports unbalanced supplies (e.g., +80V/−10V), and maintains stable operation into capacitive loads up to 1nF with external compensation. The device's safe operating area (SOA) is defined for ±40V supplies and requires thermal derating above 85°C ambient per its 100°C/W junction-to-ambient thermal resistance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | ±10V to ±45V - enables direct interface with high-voltage rails without external level-shifting or charge pumps. |
| Slew Rate | 15 V/µs - supports full-power bandwidth of 70 kHz at 70VPP output, suitable for fast transient response in piezo actuation. |
| Input Bias Current | ±10 pA (typ) - permits use of high-value feedback resistors (>10 MΩ) without significant DC error or noise degradation. |
| Output Current | ±15 mA - drives moderate loads like 2.3 kΩ at ±35V swing; sufficient for buffer stages in HV regulators and data acquisition front-ends. |
| Input Offset Voltage | ±1.5 mV (max, −25°C to +85°C) - ensures <0.004% gain error in unity-gain configurations at 35V output range. |
| Common-Mode Range | (V−) + 5 V to (V+) − 5 V - allows input signals within 5V of either rail, critical for single-supply HV sensing with ground-referenced inputs. |
| Thermal Resistance θJA | 100 °C/W (PDIP) - limits continuous power dissipation to 0.7W at +85°C ambient before reaching 125°C junction limit. |
Pinout & Package
OPA445AP is housed in an 8-pin plastic dual in-line package (PDIP-8) with standard op amp pinout and case connected to V−. Thermal resistance is 100°C/W (no heatsink); maximum junction temperature is +125°C.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Offset Trim (−) | Connects to wiper of 100kΩ potentiometer for nulling input offset voltage; not for system-level trimming. |
| 2 | Inverting Input (−In) | Differential input node with 1014 Ω common-mode impedance; requires guarding in high-Z sensor interfaces. |
| 3 | Non-inverting Input (+In) | FET-input node; input bias current flows out of pin (±10pA), affecting high-impedance source matching. |
| 4 | V− (Negative Supply) | Power supply pin; case is internally bonded to this pin - must be connected to system ground or negative rail. |
| 5 | Offset Trim (+) | Second terminal of offset trim network; forms balanced bridge with Pin 1 to adjust input stage mismatch. |
| 6 | Output | Class-AB output stage capable of ±15mA sourcing/sinking; exhibits 220Ω open-loop output impedance. |
| 7 | V+ (Positive Supply) | Power supply pin; bypass with ≥0.1µF ceramic capacitor placed within 5mm of pin to suppress HF oscillation. |
| 8 | NC | No internal connection - may be left floating or tied to V+, V−, or GND per layout requirements; no electrical function. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | Enables 10pA input bias current and 1014 Ω input impedance, preserving signal integrity in electrometer-grade sensor conditioning. |
| Laser-trimmed input offset | ±1.5mV max over −25°C to +85°C reduces calibration burden in precision HV instrumentation and automated test systems. |
| Standard pinout compatibility | Shares identical 8-pin layout with TO-99, SO-8, and PowerPAD variants - simplifies prototyping and multi-package BOM management. |
| Unbalanced supply support | Operates with asymmetric rails (e.g., +80V/−10V), enabling flexible power architecture in industrial HV modules without rail-splitting circuitry. |
| Capacitive load drive capability | Stable with >1nF loads when compensated per Figure 3 (SBOA015), making it suitable for driving long cables or piezoelectric transducers directly. |
Applications
| Test Equipment | High-Voltage Regulators |
|---|---|
Use Scenario: Precision DC voltage source in automated test equipment requiring 0–±40V programmable output with <0.01% linearity. IC Role / Device Role / Timing Role: Acts as error amplifier in series-pass regulator topology, comparing DAC reference against sensed output via high-resistance divider. Use Value: Low input bias current prevents loading of high-ratio resistive dividers; ±45V supply headroom ensures regulation stability under full-load transients. | Use Scenario: Output stage in laboratory-grade bench power supply delivering ±35V at 10mA with remote sense capability. IC Role / Device Role / Timing Role: Serves as high-voltage buffer between control loop and pass transistor base/gate, isolating sensitive feedback circuitry from HV noise. Use Value: 15V/µs slew rate enables <10µs recovery from 100% load step; ±15mA output sustains gate drive for discrete HV MOSFETs. |
| Piezo Drivers | Data Acquisition Front-Ends |
Use Scenario: Bipolar drive for piezoelectric actuators in nanopositioning stages requiring ±45V swing and sub-micron resolution. IC Role / Device Role / Timing Role: Configured as non-inverting amplifier with gain ≥10 to boost DAC output while maintaining low THD+N (0.00008% at 10Vrms). Use Value: Ultra-low input bias current avoids charge accumulation on piezo capacitance; wide CMRR (95dB) rejects supply ripple in closed-loop position control. | Use Scenario: Signal conditioning stage for strain gauge bridges in structural health monitoring systems operating from ±36V rails. IC Role / Device Role / Timing Role: Performs low-noise, high-common-mode rejection amplification (G = 100) before 24-bit sigma-delta ADC sampling at 10kSPS. Use Value: 15nV/√Hz input voltage noise and 6fA/√Hz current noise minimize total integrated noise floor; laser-trimmed offset ensures <1µV drift over 8-hour measurement cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA445AU | Same silicon die, SO-8 surface-mount package; θJA = 150°C/W vs. 100°C/W for OPA445AP; no through-hole mounting option. | Preferred for space-constrained PCBs and automated assembly; unsuitable for prototyping with breadboards or wire-wrap. | Select OPA445AU when board real estate is limited and reflow soldering is available; verify thermal pad layout per TI SLMA002 if using PowerPAD variant. |
| OPA445ADDA | Same die, SO-8 PowerPAD package; θJA = 52°C/W with heat-spreader; exposed thermal pad must be soldered to V− plane. | Required for continuous >500mW dissipation at +85°C ambient; eliminates need for external heatsinks in compact HV modules. | Choose OPA445ADDA for production designs needing >1W sustained output power; mandatory copper land and via pattern per Figure 14 required. |
Compared with OPA445AU and OPA445ADDA, the OPA445AP offers lowest thermal resistance among through-hole op amps (100°C/W), easiest hand-soldering and socket-based validation, and identical AC/DC specs - making it optimal for lab-grade instruments and low-volume HV prototypes where mechanical robustness and debug flexibility outweigh density constraints.
Availability
OPA445AP is available at Aetrix Electronics and suitable for test equipment, high-voltage regulators, and piezo drivers requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for OPA445AP 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of heritage in precision op amp design and high-reliability manufacturing.
The OPA445 product line targets high-voltage industrial and instrumentation applications demanding wide supply range, low input bias, and robust thermal performance - specifically engineered for test, measurement, and actuation systems operating beyond ±30V rails.
FAQ
What is the maximum supply voltage rating for the OPA445AP?
The OPA445AP has an absolute maximum supply rating of ±50V, but its specified operating range is ±10V to ±45V. Operation at ±45V is fully characterized across −25°C to +85°C, with guaranteed performance including 15V/µs slew rate and ±15mA output current. Exceeding ±45V risks violating SOA limits and invalidates parametric guarantees.
Does the OPA445AP require external compensation for unity-gain stability?
Yes, the OPA445AP is not unity-gain stable. It requires minimum noise gain ≥5 for unconditional stability per the datasheet. For G = 1 applications, external compensation (e.g., capacitor across Rf) or gain-setting networks must be used. Figure 1 shows a noninverting configuration with G = 1 + R2/R1, and stability analysis guidelines are provided in Application Bulletin SBOA015.
How should the NC pin (Pin 8) of the OPA445AP be handled in PCB layout?
Pin 8 of the OPA445AP is explicitly designated "NC" (no internal connection) in the datasheet. It may be left floating, tied to V+, V−, or GND based on mechanical or EMI considerations - but must never be used as a thermal pad or ground return path. No current flows through this pin, and its state has zero effect on electrical performance or offset trimming.
Can the OPA445AP drive capacitive loads without oscillation?
The OPA445AP can drive capacitive loads up to ~100pF without compensation, but larger loads (e.g., 1nF piezo transducers) require external RC compensation per Figure 3. Uncompensated operation into >500pF typically causes overshoot (>35%) or ringing. TI's SBOA015 bulletin details calculation methods for RC and CC values to restore phase margin above 45°.
What is the purpose of the offset trim pins (1 and 5) on the OPA445AP?
The offset trim pins (1 and 5) on the OPA445AP allow adjustment of input offset voltage using a 100kΩ potentiometer connected between them, with wiper to V−. This nulls only the amplifier's intrinsic offset - not system-level errors - and must be performed at operating temperature with no input signal. Improper use (e.g., trimming system offset) degrades long-term drift performance.
OPA445AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 15V/µs
- Gain Bandwidth Product:
- 2 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 10 pA
- Voltage - Input Offset:
- 1.5 mV
- Current - Supply:
- 4.2mA
- Current - Output / Channel:
- 15 mA
- Voltage - Supply Span (Min):
- 20 V
- Voltage - Supply Span (Max):
- 90 V
- Operating Temperature:
- -25°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
OPA445AP FAQ
1.How can I place an order for OPA445AP through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA445AP 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 OPA445AP reliable?
The price and inventory of OPA445AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA445AP is usually 5 days.
3.What payment methods are accepted for OPA445AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA445AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA445AP?
OPA445AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA445AP 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 OPA445AP?
For technical support, including OPA445AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA445AP requirements.
6.How does Aetrix verify that OPA445AP is sourced from the original manufacturer or authorized distributors?
All OPA445AP 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 OPA445AP meets industry standards.
7.What is the process for return or replacement of OPA445AP?
All OPA445AP units undergo pre-shipment inspection (PSI). If there is an issue with OPA445AP, 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 OPA445AP part is unused and in its original packaging.
Return procedure for OPA445AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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