ADL5309ACBZ-RL

Overview

The ADL5309ACBZ-RL is a dual-channel logarithmic converter manufactured by Analog Devices Inc. It features two monolithic logarithmic transimpedance amplifiers optimized for measuring low-frequency and wide dynamic range optical signal power in fiber optic systems. The device provides highly accurate, temperature-compensated output voltages proportional to the logarithm of the input current ratio. It includes an integrated 14-bit SAR ADC accessible via an I2C interface, adaptive photodiode biasing through PDB interfaces, and operates within a supply voltage range of 2.85 V to 5.25 V. The component supports an electrical dynamic range of 188 dB and an optical dynamic range of 94 dB, with a specified operating temperature range from -40°C to +105°C.

Feature Summary

• Dual-channel current inputs enable direct optical gain measurements with high accuracy.
• Integrated 14-bit successive approximation register (SAR) ADC allows digital readout of channel outputs and temperature data via I2C.
• Adaptive photodiode biasing minimizes dark current at low currents and prevents saturation nonlinearity at high currents.
• Factory-trimmed logarithmic response ensures consistent slope and intercept across the operating temperature range.

Applications

• Automatic test equipment
• Optical power monitoring
• Machine automation
• Optical modules

Procurement Notes

Verify the specific package suffix and reel configuration against the manufacturer's official ordering guide before procurement. Confirm that the I2C address selection pin (SBA) requirements align with the system bus topology. Ensure that the thermal management design accounts for the junction-to-ambient resistance characteristics of the WLCSP package under maximum load conditions.

Selection Notes

Select this component when precise measurement of low-level photocurrents over a wide dynamic range is required. The integrated ADC and I2C interface simplify system architecture by reducing external component count. Consider the adaptive biasing capabilities if the application involves photodiodes with significant series resistance or varying dark current characteristics across different temperatures.

Part Context

The ADL5309 belongs to the ADL5309 family of logarithmic converters designed for fiber optic applications. It is distinct from standard linear transimpedance amplifiers due to its inherent dynamic range compression. The ACBZ-RL designation indicates the specific wafer level chip scale package and reel packaging format used for surface mount assembly.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.

FAQ

How does the ADL5309 handle photodiode biasing?

The device supports adaptive photodiode biasing through the PDB1 and PDB2 interfaces. At low diode currents, the reverse bias is kept small to minimize dark current, while at higher currents, the bias voltage scales linearly to avoid saturation nonlinearity.

What is the function of the SUM pins?

The SUM pins act as guard pins that shield the current lines to INP1 and INP2. They are internally connected together and should not be grounded to prevent interference with sensitive current measurements.

Can multiple ADL5309 devices operate on the same I2C bus?

Yes, up to three devices can communicate independently over a single I2C bus. The serial bus address is configured by applying a specific voltage level to the SBA pin.