用于IRFPA ROIC的高性能缓冲器模块的设计

红外焦平面读出电路(IRFPA ROIC)主要用于焦平面阵列与后续信号处理之间的通信.文章提出了一种用于红外焦平面读出电路的缓冲器模块,包括列缓冲器、高性能的输出缓冲器以及相应的偏置电路.缓冲器均采用单位增益放大器结构,通过放大器的优化设计可实现对不同负载的有效驱动且静态功耗较低.该缓冲器模块用于一款640×512面阵、30μm中心距的中波红外焦平面读出电路,采用CSMC 0.5μm DPTM工艺进行流片加工.仿真结果表明,列缓冲器的开环增益为40.00 dB,单位增益带宽为48.17 MHz(10 pF).输出缓冲器可实现轨到轨的输入,开环增益为39.68 dB,单位增益带宽为46.08 MHz,读出速率高达20 MHz,功耗为16.02 mW(25 pF//5.1 kΩ).该模块输入端拉出的测试管脚可在焦平面读出电路的晶圆测试中帮助验证芯片功能.通过调节测试端口,测试结果与仿真结果大体一致,验证了该缓冲器模块的设计可行.

Design of High-performance Buffer Module for IRFPA ROIC

The infrared focal plane readout circuit is mainly used for the communication between the focal plane array and the subsequent signal processing.This paper proposes a buffer module for IRFPA ROIC,including the column buffer,high-performance output buffer,and the corresponding bias circuit.The buffers use the unity gain amplifier architecture and the effective drive of different loads can be realized while the static power consumption is low through the optimization design of amplifier.The module has been applied to a 640 × 512 MW IRFPA ROIC with 15μm pixel pitch and taped out by CSMC 0.5 μm DPTM CMOS process.The simulation results show that the open loop gain of column buffer is 40.00 dB,the unit gain bandwidth is 48.17 MHz(10 pF).The output buffer can realize the rail-to-rail input and the open loop gain is 39.68 dB,the unit gain bandwidth is 46.08 MHz,the readout rate is up to 20 MHz and power consumption is 16.02 mW (25 pF//5.1 kΩ).The test pin which is the input port of the module can help verify chip functions in the ROIC wafer testing.By adjusting the test port,the test results are in good agreement with the simulation results,which verifies the feasibility of the design of the buffer module.