Texas Instruments ISO100BP

Overview

ISO100BP from Burr-Brown is an optically-coupled linear isolation amplifier with 750V continuous isolation voltage, 60kHz small-signal bandwidth, and ultra-low 0.3µA max AC leakage at 240V/60Hz. It operates as a current-to-voltage converter (V_OUT = I_INR_F) or voltage-input amplifier (V_OUT/V_IN = R_F/R_IN), supporting unipolar and bipolar configurations for industrial transducer sensing and 4–20mA loop isolation.

For engineers reviewing the ISO100BP datasheet, ISO100BP pinout, ISO100BP application, or ISO100BP equivalent, key selection criteria include its tested 2500V DC breakdown rating, laser-trimmed optical matching for <0.1% nonlinearity, ±25°C to +85°C operating range, and 18-pin bottom-braze DIP package with isolated input/output commons.

Technical Context

The ISO100BP uses a single LED with dual matched photodiodes (D1, D2) to achieve galvanic isolation: negative feedback via D1 stabilizes the input stage (A1), while signal transfer occurs forward through D2 to the output stage (A2). This architecture enables high accuracy without relying on absolute component performance-only optical match matters.

It supports both unipolar (I_IN = –20µA to –0.02µA) and bipolar (I_IN = ±10µA) operation using two precision internal reference current sources (10.5–12.5µA nominal, 50nA matching). Gain is set externally via R_F, and offset errors are minimized by active laser trimming of V_OSI/V_OSO (<200µV initial) and I_OS (<35nA in bipolar mode).

Key Specifications

Pinout & Package

ISO100BP is housed in an 18-pin bottom-braze DIP (Package Drawing #220), providing mechanical robustness and hermetic sealing for long-term reliability in harsh environments. The package features separate input and output common pins to maintain galvanic isolation integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar isolation amplifier applications.

Compared with AMC1301DWV and ISO124P, ISO100BP offers superior DC precision (200µV offset, 0.02% nonlinearity) and built-in bipolar reference sources-making it optimal for low-drift, low-frequency isolation tasks like thermocouple amplification and 4–20mA loop conversion where optical stability trumps speed.

Availability

ISO100BP is available at Aetrix Electronics and suitable for industrial process control, biomedical instrumentation, and test equipment requiring stable component supply with long-term lifecycle assurance.

Supply support for ISO100BP 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

Burr-Brown Corporation was a U.S.-based analog IC design leader, acquired by Texas Instruments in 2000, known for high-precision signal conditioning products.

The ISO100BP belongs to Burr-Brown's optically-isolated amplifier family, engineered specifically for high-accuracy analog signal transmission across safety-critical isolation barriers in industrial and medical systems.

FAQ

What is the maximum continuous isolation voltage rating for ISO100BP?

The ISO100BP is rated for 750V continuous AC or DC isolation voltage, verified by 2500V DC breakdown testing for 10 seconds. This rating applies under specified operating conditions including ambient temperature up to +85°C and proper PCB layout with ≥8mm creepage distance between input and output traces. The ISO100BP maintains this isolation performance across its full –25°C to +85°C operating temperature range.

How does ISO100BP achieve low nonlinearity without external calibration?

The ISO100BP achieves ≤0.02% typical nonlinearity through laser-trimming of its internal optical components-specifically the LED and dual photodiodes-to ensure precise light-output and photocurrent matching. This optical matching, combined with negative feedback via the D1 photodiode path, makes gain dependent on ratio-matching rather than absolute device parameters. As a result, the ISO100BP delivers stable linearity without requiring system-level calibration or external trimming components.

Can ISO100BP operate in both unipolar and bipolar modes, and how is the mode selected?

Yes, ISO100BP supports both unipolar and bipolar operation. Unipolar mode (I_IN = –20µA to –0.02µA) is enabled by connecting pins 16 and 17, while bipolar mode (I_IN = ±10µA) requires connecting pins 15 and 16. The device includes two internal 12µA reference current sources (I_REF1, I_REF2) that automatically configure for bipolar center-zero operation when enabled. This pin-strappable flexibility allows one ISO100BP design to serve multiple sensor types without hardware changes.

What is the role of the BAL pins (12–15) on ISO100BP, and are they mandatory?

The BAL pins (12, 13, 14, 15) on ISO100BP provide access to internal balance nodes for optimizing common-mode rejection and thermal drift performance. They are not mandatory for basic operation but become essential when achieving the datasheet-specified 90dB CMRR at 60Hz or minimizing temperature-induced gain shift. External 100kΩ potentiometers connected across these pins allow fine-tuning of optical path symmetry-critical for applications demanding <0.01%/°C gain stability across –25°C to +85°C.

Does ISO100BP require external components for basic voltage-input operation?

Yes, ISO100BP requires one external resistor (R_IN) for basic voltage-input operation: V_OUT/V_IN = R_F/R_IN, where R_F is the internal feedback resistor (typically 1MΩ). The input voltage is applied differentially across pins 3 (+In) and 7 (–In), with R_IN connected from +In to signal source. No additional active components are needed-the ISO100BP's laser-trimmed architecture ensures gain accuracy and offset stability without external op-amps or trimming networks.