1.25-Gb/s regulated cascode CMOS transimpedance amplifier for Gigabit Ethernet applications

A transimpedance amplifier (TIA) has been realized in a 0.6-/spl mu/m digital CMOS technology for Gigabit Ethernet applications. The amplifier exploits the regulated cascode (RGC) configuration as the input stage, thus achieving as large effective input transconductance as that of Si Bipolar or GaAs MESFET. The RGC input configuration isolates the input parasitic capacitance including photodiode capacitance from the bandwidth determination better than common-gate TIA. Test chips were electrically measured on a FR-4 PC board, demonstrating transimpedance gain of 58 dB/spl Omega/ and -3-dB bandwidth of 950 MHz for 0.5-pF photodiode capacitance. Even with 1-pF photodiode capacitance, the measured bandwidth exhibits only 90-MHz difference, confirming the mechanism of the RGC configuration. In addition, the noise measurements show average noise current spectral density of 6.3 pA//spl radic/(Hz) and sensitivity of -20-dBm for a bit-error rate of 10/sup -12/. The chip core dissipates 85 mW from a single 5-V supply.     

6 GHz transimpedance amplifier for optical sensing system in low-cost 0.35 /spl mu/m CMOS

A high-speed transimpedance amplifier (TIA) has been designed and implemented in a low cost 0.35 mum CMOS technology. Combining the techniques of regulated cascode input stage, current shunt feedback and inductive-series peaking, the TIA achieves a transimpedance gain of 51 dBOmega and 3 dB bandwidth of 6 GHz, in the presence of a photodiode capacitance of 0.6 pF. This is believed to be the fastest TIA ever reported in 0.35 mum CMOS technology     

1-Gb/s 80-dB/spl Omega/ fully differential CMOS transimpedance amplifier in multichip on oxide technology for optical interconnects

A 1-Gb/s differential transimpedance amplifier (TIA) is realized in a 0.25-/spl mu/m standard CMOS technology, incorporating the regulated cascode input configuration. The TIA chip is then integrated with a p-i-n photodiode on an oxidized phosphorous-silicon (OPS) substrate by employing the multichip-on-oxide (MCO) technology. The MCO TIA demonstrates 80-dB/spl Omega/ transimpedance gain, 670-MHz bandwidth for 1-pF photodiode capacitance, 0.54-/spl mu/A average input noise current, -17-dBm sensitivity for 10/sup -12/ bit-error rate (BER), and 27-mW power dissipation from a single 2.5-V supply. It also shows negligible switching noise effect from an embedded VCO on the OPS substrate. Furthermore, a four-channel MCO TIA array is implemented for optical interconnects, resulting in less than -40-dB crosstalk between adjacent channels.     

Area-efficient CMOS transimpedance amplifier for optical receivers

In this letter, a broadband area-efficient transimpedance amplifier (TIA) for optical receivers is designed using a standard 0.18 μm CMOS technology. A new shunt–shunt peaking technique is used at the input transimpedance stage, which is followed by a gain stage and a capacitive degeneration stage. The amplifier achieves a wide bandwidth with only one inductor; hence a smaller silicon area is maintained. The proposed TIA has a measured transimpedance gain of 50 dB Ohm and a −3 dB bandwidth of 6.5 GHz for 0.25 pF input photodiode capacitance. It consumes DC power of 14 mW from a 1.8 V supply voltage and occupies only 0.09 mm² silicon area.     

Design of broadband transimpedance amplifier for optical communication systems

This paper describes the design and analysis of broadband transimpedance amplifiers (TIAs) based on Regulated Cascode (RGC) configuration. The focus is to deal with bandwidth restriction occurring in optical receivers coming from TIA input parasitic capacitances. Despite the conventional method for broadband RGC TIA design that a ladder matching network is employed to isolate the input capacitance of TIA and the photodiode capacitance, the proposed TIA eliminates the effects of these parasitic components by absorbing them in a T-matching network. The conventional broadband RGC TIA is analyzed and the disadvantages of the ladder matching network is demonstrated in a TIA design example. The proposed RGC TIA is simulated on 0.18-μm standard RF CMOS process. The simulation results presented show that the Gain-Bandwidth product (GBW) is extended by a larger factor compared to that of the conventional broadband RGC TIA while the biasing conditions and the value of the photodiode capacitance are considered the same.     

Low-power 10 Gb/s inductorless inverter based common-drain active feedback transimpedance amplifier in 40 nm CMOS

This study presents an inductorless 10 Gb/s transimpedance amplifier (TIA) implemented in a 40 nm CMOS technology. The TIA uses an inverter with active common-drain feedback (ICDF-TIA). The TIA is followed by a two-stage differential amplifier and a 50 Ω differential output driver to provide an interface to the measurement setup. The optical receiver shows measured optical sensitivities of ?17.7 and ?16.2 dBm at BER = 10^?12 for data rates of 8 and 10 Gb/s, respectively. The TIA has a simulated transimpedance gain of 47 dBΩ, 8 GHz bandwidth with 0.45 pF total input capacitance for the photodiode, ESD protection and input PAD. The TIA occupies 0.0002 mm² whereas the complete optical receiver occupies a chip area of 0.16 mm². The power consumption of the TIA is only 2.03 mW and the complete chip dissipates 17 mW for a 1.1 V single supply voltage. The complete optical receiver has a measured transimpedance gain of 57.5 dBΩ.     

8 Gbits/s inductorless transimpedance amplifier in 90 nm CMOS technology

This work presents the design and the measured performance of a 8 Gb/s transimpedance amplifier (TIA) fabricated in a 90 nm CMOS technology. The introduced TIA uses an inverter input stage followed by two common-source stages with a 1.5 kΩ feedback resistor. The TIA is followed by a single-ended to differential converter stage, a differential amplifier and a 50 Ω differential output driver to provide an interface to the measurement setup. The optical receiver shows a measured optical sensitivity of ?18.3 dBm for a bit error rate = 10^?9. A gain control circuitry is integrated with the TIA to increase its input photo-current dynamic range (DR) to 32 dB. The TIA has an input photo-current range from 12 to 500 μA without overloading. The stability is guaranteed over the whole DR. The optical receiver achieves a transimpedance gain of 72 dBΩ and 6 GHz bandwidth with 0.3 pF total input capacitance for the photodiode and input PAD. The TIA occupies 0.0036 mm² whereas the complete optical receiver occupies a chip area of 0.46 mm². The power consumption of the TIA is only 12 mW from a 1.2 V single supply voltage. The complete chip dissipates 60 mW where a 1.6 V supply is used for the output stages.     

A linear and wide dynamic range transimpedance amplifier with adaptive gain control technique

A linear and wide dynamic range transimpedance amplifier (TIA) for the pulsed time-of-flight imaging LADAR application has been designed and simulated in a 0.18 μm 3.3 V CMOS technology. Specific design techniques, including adaptive gain control technique to widen linear dynamic range, pseudo-differential structure of the front end to decrease the common-mode noise and noise minimization to improve SNR, have been proposed to achieve challenging designs goals with linear dynamic range of 5000:1, high transimpedance gain of 89 dB Ω, bandwidth up to 150 MHz, equivalent input-referred noise current less than 8 \({\text{pA}}/\sqrt {\text{Hz}}\), in 2 pF photodiode parasitic capacitance. The proposed TIA consumes 165 mW with 3.3 V power supply.     

A 40 mW 3 Gb/s Self-Compensated Differential Transimpedance Amplifier With Enlarged Input Capacitance Tolerance in 0.18 $mu$m CMOS Technology

By combining an appropriate differential-sensing scheme with the bootstrapping technique, this paper presents a self-compensated design topology which is shown to be effective at reducing the loading effects due to the photodiode and the ESD protection circuit at the differential inputs. The built-in offset creation technique is introduced to overcome voltage headroom limitation. Furthermore, the negative impedance compensation is employed to enhance the gain-bandwidth product. The IC is shown to be tolerant of ESD protection circuit with 0.5 pF equivalent capacitance at the differential inputs. While connected to an InGaAs PIN photodiode exhibiting 0.8 pF equivalent capacitance, the implemented IC has achieved a differential transimpedance gain of 3.5 kOmega and a -3 dB bandwidth of 1.72 GHz. At a data rate of 3 Gb/s, the measured dynamic range is from -20 dBm to +0 dBm at a bit-error rate of 10^-12 with a 2³¹ -1 pseudorandom test pattern. The negative impedance compensation is shown to achieve enhancement factors of 4.5 dB and 520%, respectively, for transimpedance gain and - 3 dB bandwidth. The IC totally consumes 40 mW from a 1.8 V supply.     

A CMOS imaging diversity receiver for gigabit free-space optical MIMO

A 7-channel imaging diversity receiver based on current-summing is implemented in a 180 nm CMOS technology for broadband free-space optical (FSO) multi-input/multi-output (MIMO) communication. Each channel employs a low input-impedance current mirror (CM) as the input stage, which allows the implementation of direct current-summing for equal-gain combining (EGC). The summed current signal drives a second stage transimpedance amplifier (TIA) to generate the output voltage. Electrical characterization was performed using a photodiode emulation circuit and chip-on-board FR-4 assembly, demonstrating a total transimpedance gain of 62 dBΩ, −3 dB bandwidth of 1.2 GHz, and eye diagrams up to 2 Gb/s for 0.25 pF photodiode capacitance. The theoretical sensitivity of the imaging receiver is −16.8 dBm for a bit error rate (BER) of 10⁻⁹ at a photodetector responsivity of 0.4 A/W. The simulated power consumption for a single front-end amplifier circuit is 4.2 mW, and for the second stage TIA is 10.3 mW from a single 1.8 V supply. The diversity receiver is flip-chip compatible to enable hybrid integration to a custom InGaAs photodetector array.     

10 Gb/s OEIC optical receiver front-end and 3.125 Gb/s PHEMT limiting amplifier

A 10 Gb/s OEIC (optoelectronic integrated circuit) optical receiver front-end has been studied and fab ricated based on the φ-76 mm GaAs PHEMT process; this is the first time that a limiting amplifier (LA) has been designed and realized using depletion mode PHEMT. An OEIC optical receiver front-end mode composed of an MSM photodiode and a current mode transimpedance amplifier (TIA) has been established and optimized by simu lation software ATLAS. The photodiode has a bandwidth of 10 GHz, a capacitance of 3 fF/μm and a photosensitive area of 50×50 μm~2. The whole chip has an area of 1511×666 μm~2. The LA bandwidth is expanded by spiral inductance which has been simulated by software HFSS. The chip area is 1950×1910μm~2 and the measured results demonstrate an input dynamic range of 34 dB (10-500 mVpp) with constant output swing of 500 tnVpp.     

A Bandwidth Enhanced Transimpedance Amplifier with Improved Noise Performance

A new TIA topology with enhanced bandwidth is presented in this paper. By adding an extra capacitive feedback loop to the resistive feedback TIA, bandwidth and sensitivity are increased without sacrificing the low power consumption. It is shown that this topology is superior to the self-compensated TIA when the photodiode is integrated on the same die as the TIA. An implementation is presented that boosts the bandwidth by a factor of 9 and reduces the noise by a factor of 4.2 for a photodiode capacitance of 106 pF, the parasitic capacitance of a POF-compliant 1 mm integrated photodiode in 130 nm CMOS.     

Low voltage second-order alpha function synapse

This paper introduces a Transimpedance Amplifier (TIA) design capable of producing an incremental input resistance in the ohmic range, for input signals in the microampere range, such as are encountered in the design of instrumentation for electrochemical ampero-metric sensors, optical-sensing and current-mode circuits. This low input-resistance is achieved using an input stage incorporating negative feedback. In a Cadence simulation of an exemplary design using a 180 nm CMOS process and operating with?±?1.8 V supply rails, the input resistance is 1.05 ohms and the power dissipation is 93.6 µW. The bandwidth, for a gain of 100 dBohm, exceeded 9 MHz. For a 1µA, 1 MHz sinusoidal input signal the Total Harmonic Distortion, with this gain, is less than 1%. The input referred noise current with zero photodiode capacitance is 2.09 pA/√Hz and with a photodiode capacitance of 2pF is 8.52 pA/√Hz. Graphical data is presented to show the effect of a photodiode capacitance varying from 0.5 to 2 pF, when the TIA is used in optical sensing. In summary, the required very low input resistance, at a low input current level (µA) is achieved and furthermore a Table is included comparing the characteristics and a widely used Figure of Merit (FOM) for the proposed TIA and similar published low-power TIAs. It is apparent from the Table that the FOM of the proposed TIA is better than the FOMs of the other TIAs mentioned.

     

Broad-Band Design Techniques for Transimpedance Amplifiers

In this paper, a novel bandwidth enhancement technique based on the combination of capacitive degeneration, broad-band matching network, and the regulated cascode (RGC) input stage is proposed and analyzed, which turns the transimpedance amplifier (TIA) design into a fifth-order low-pass filter with Butterworth response. This broad-band design methodology for TIAs is presented with an example implemented in CHRT 0.18-mum 1.8-V RF CMOS technology. Measurement data shows a -3-dB bandwidth of about 8 GHz with 0.25-pF photodiode capacitance. Comparing with the core RGC TIA without capacitive degeneration and broad-band matching network, this design achieves an overall bandwidth enhancement ratio of 3.6 with very small gain ripple. The transimpedance gain is 53 dBOmega with a group delay of 80plusmn20 ps. The chip consumes only 13.5-mW dc power and the measured average input-referred noise current spectral density is 18 pA/radicHz up to 10 GHz     

1Gb/s CMOS调节型共源共栅光接收机

基于特许0.35μm EEPROM CMOS标准工艺设计了一种单片集成光接收机芯片,集成了双光电探测器(DPD)、调节型共源共栅(RGC)跨阻前置放大器(TIA)、三级限幅放大器(LA,limiting amplifier)和输出电路,其中RGCTIA能够隔离光电二极管的电容影响,并可以有效地扩展光接收机的带宽。测试结果表明,光接收机的3dB带宽为821MHz,在误码率为10-9、灵敏度为-11dBm的条件下,光接收机的数据传输速率达到了1Gb/s;在3.3V电压下工作,芯片的功耗为54mW。     

A 40 Gbit/s fully integrated optical receiver analog front-end in 90 nm CMOS

A fully integrated 40 Gbit/s optical receiver analog front-end (AFE) including a transimpedance amplifier (TIA) and a limiting amplifier (LA) for short distance communication is described in this paper.The proposed TIA employs a modified regulated cascode (RGC) configuration as input stage,and adopts a third order interleaving active feedback gain stage.The LA utilizes nested active feedback,negative capacitance,and inductor peaking technology to achieve high voltage gain and wide bandwidth.The tiny photo current received by the receiver AFE is amplified to a single-ended voltage swing of 200 mV(p p).Simulation results show that the receiver AFE provides conversion gain of up to 83 and bandwidth of 34.7 GHz,and the equivalent input noise current integrated from 1 MHz to 30 GHz is about 6.6 μA(rms).     

20 mW 1.25 Gbit/s CMOS transimpedance amplifier with 30 dB dynamic range

A 1.25 Gbit/s transimpedance amplifier using a novel photodiode capacitance cancellation technique has been demonstrated in 0.35 mum CMOS technology. The transimpedance amplifier achieved a transimpedance gain of 17.1 kOmega as well as a wide dynamic range from +1 to -29 dBm while consuming only 20 mW from a 3 V supply     

Bandwidth enhancement for transimpedance amplifiers

A technique for bandwidth enhancement of a given amplifier is presented. Adding several interstage passive matching networks enables the control of transfer function and frequency response behavior. Parasitic capacitances of cascaded gain stages are isolated from each other and absorbed into passive networks. A simplified design procedure, using well-known low-pass filter component values, is introduced. To demonstrate the feasibility of the method, a CMOS transimpedance amplifier (TIA) is implemented in a 0.18-/spl mu/m BiCMOS technology. It achieves 3 dB bandwidth of 9.2 GHz in the presence of a 0.5-pF photodiode capacitance. This corresponds to a bandwidth enhancement ratio of 2.4 over the amplifier without the additional passive networks. The transresistance gain is 54 dB/spl Omega/, while drawing 55 mA from a 2.5-V supply. The input sensitivity of the TIA is -18 dBm for a bit error rate of 10/sup -12/.     

A 3.125-Gb/s inductorless transimpedance amplifier for optical communication in 0.35μm CMOS

A 3.125-Gb/s transimpedance amplifier(TIA) for an optical communication system is realized in 0.35μm CMOS technology.The proposed TIA employs a regulated cascode configuration as the input stage, and adopts DC-cancellation techniques to stabilize the DC operating point.In addition,noise optimization is processed. The on-wafer measurement results show the transimpedance gain of 54.2 dBΩand -3 dB bandwidth of 2.31 GHz.The measured average input referred noise current spectral density is about 18.8 pA/(?).The measured eye diagram is clear and symmetrical for 2.5-Gb/s and 3.125-Gb/s PRBS.Under a single 3.3-V supply voltage,the TIA consumes only 58.08 mW,including 20 mW from the output buffer.The whole die area is 465×435μm~2.     

High-gain differential CMOS transimpedance amplifier with on-chip buried double junction photodiode

An integrated fully differential CMOS transimpedance amplifier (TIA) with buried double junction photodiode input is described. The TIA features a variable high transimpedance gain (250 k/spl Omega/ to 2.5 M/spl Omega/), large DC photocurrent rejection capability (>55 dB) and low input referred noise density at 100 kHz (2pA//spl radic/Hz).