Features and Benefits
- High Output Voltage: Up to 75V
- Integrated Schottky Diode
- 75V, 350mA Internal Switch
- High Side Fixed Voltage Drop APD Current Monitor
- Adjustable Frequency: 250kHz to 2MHz
- Frequency Synchronization
- Wide VIN Range: 2.7V to 20V
- Constant-Voltage and Constant-Current Regulation
- Programmable Current Limit Protection
- Surface Mount Components
- Low Shutdown Current <1μA
- Internal Soft-Start
- Internal Compensation
- CTRL Pin Allows Output Adjustment with No Polarity Inversion
- 3mm × 3mm 16-Lead QFN Package
The LT3571 is a current mode step-up DC/DC converter designed to bias avalanche photodiodes (APDs) in optical receivers with an output voltage up to 75V. The LT3571 features a high side fixed voltage drop APD current monitor with better than 10% relative accuracy over the entire temperature range. The integrated power switch, Schottky diode and APD current monitor allow a small solution footprint and low solution cost. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. The inductor-based topology ensures an input free from switching noise. The integrated high side current monitor produces a current proportional to the APD current with better than 10% relative accuracy over four decades of dynamic range in the input range of 250nA to 2.5mA. This current can be used as a reference to provide a digitally programmed output voltage via the CTRL pin. The LT3571 is available in the tiny footprint (3mm × 3mm) 16-lead QFN package.
- APD Bias
- PIN Diode Bias
- Optical Receivers and Modules
- Fiber Optic Network Equipment
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
The ADA4355 is a complete, high performance, current input µModule®. For space savings, the ADA4355 includes all required active and passive components to comprise a complete current-to-bits data acquisition channel supporting small form-factor optical modules as well as multi-channel systems.
The high-speed TIA of the device supports 10 ns pulse widths, allowing high spatial resolution for time-of-flight measurements. Additionally, the ADA4355 includes three TIA gain (TZ) settings to maximize dynamic range. An internal, selectable, analog low-pass filter (LPF) can limit the device bandwidth with a corner frequency of 100 MHz to minimize broadband noise while also serving as an anti-aliasing filter for the 125 MSPS ADC. For lower bandwidth signals or wider signal pulses (e.g. 20μs or larger), the filter can be set to a corner frequency of 1.0 MHz to provide additional noise reduction.
The 14-bit ADC converts the amplified voltage signal at a rate of up to 125 MSPS and outputs the digitized signals through two serial, low voltage differential signaling (LVDS) data lanes, operating at rates of up to 1 Gbps per lane. The data clock output (DCO) operates at frequencies of up to 500 MHz and supports double data rate (DDR) operation.
The ADA4355 exhibits fast overdrive recovery from a large input current signal and is available in a 12 mm × 6mm CSP_BGA package with a −40°C to +85°C operating temperature range.
- Current-to-voltage Conversion
- Chemical analyzers
- Mass spectroscopy
- Time of Flight (ToF)
- Fiber optic sensing
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
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Models for the following parts are available in LTspice:
Press Releases (1)
Technical Articles (1)
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.