Datasheet LT6202, LT6203, LT6204 (Analog Devices) - 20
| Manufacturer | Analog Devices |
| Description | Quad 100MHz, Rail-to-Rail Input and Output, Ultralow 1.9nV√Hz Noise, Low Power Op Amps |
| Pages / Page | 28 / 20 — TYPICAL APPLICATIONS Low Noise, Low Power 1MΩ AC. Photodiode … |
| File Format / Size | PDF / 1.7 Mb |
| Document Language | English |
TYPICAL APPLICATIONS Low Noise, Low Power 1MΩ AC. Photodiode Transimpedance Amplifier. Precision Low Noise, Low Power, 1MΩ
Model Line for this Datasheet
- LT6202CS5#PBF LT6202CS5#TRMPBF LT6202CS5#TRPBF LT6202CS8#PBF LT6202CS8#TRPBF LT6202HS5#PBF LT6202HS5#TRMPBF LT6202HS5#TRPBF LT6202IS5#PBF LT6202IS5#TRMPBF LT6202IS5#TRPBF LT6202IS8#PBF LT6202IS8#TRPBF
Text Version of Document
LT6202/LT6203/LT6204
TYPICAL APPLICATIONS Low Noise, Low Power 1MΩ AC
therefore sit at a point slightly higher than one pinchoff
Photodiode Transimpedance Amplifier
voltage below ground (typically about –0.6V). When the Figure 3 shows the LT6202 applied as a transimpedance photodiode is illuminated, the current must come from the amplifier (TIA). The LT6202 forces the BF862 ultralow-noise LT6202’s output through R1 and R2, as in a normal TIA. JFET source to 0V, with R3 ensuring that the JFET has an Amplifier input noise density and gain-bandwidth product I were measured at 2.4nV/Hz and 100MHz, respectively. DRAIN of 1mA. The JFET acts as a source follower, buffering the input of the LT6202 and making it suitable for the high Note that because the JFET has a high gm, approximately impedance feedback elements R1 and R2. The BF862 has 1/80Ω, its attenuation looking into R3 is only about 2%. a minimum I Gain-bandwidth product was measured at 100MHz and DSS of 10mA and a pinchoff voltage between –0.3V and –1.2V. The JFET gate and the LT6202 output the closed-loop bandwidth using a 3pF photodiode was approximately 1.4MHz. V + S R1 R2 499k 499k
Precision Low Noise, Low Power, 1MΩ Photodiode Transimpedance Amplifier
PHILIPS Figure 4 shows the LT6202 applied as a transimpedance BF862 C1 amplifier (TIA), very similar to that shown in Figure 3. – 1pF In this case, however, the JFET is not allowed to dictate V – BIAS LT6202 VOUT the DC-bias conditions. Rather than being grounded, the + LT6202’s noninverting input is driven by the LTC2050 to the exact state necessary for zero JFET gate voltage. The R3 4.99k noise performance is nearly identical to that of the circuit VS = ±5V in Figure 3, with the additional benefit of excellent DC per- V – LT6202/03/04 F03 S formance. Input offset was measured at under 200µV and output noise was within 2mVP-P over a 20MHz bandwidth.
Figure 3. Low Noise, Low Power 1M
Ω
AC Photodiode Transimpedance Amplifier
V + S R1 R2 499k 499k PHILIPS C2 BF862 R4 C1 0.1µF 10M 1pF – V – BIAS – R5 LT6202 VOUT 10k + LTC2050HV + C3 1µF R3 4.99k VS = ±5V V – S LT6202/03/04 F04
Figure 4. Precision Low Noise, Low Power Transimpedance Amplifier
620234fd 20 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
TYPICAL APPLICATIONS Low Noise, Low Power 1MΩ AC
therefore sit at a point slightly higher than one pinchoff
Photodiode Transimpedance Amplifier
voltage below ground (typically about –0.6V). When the Figure 3 shows the LT6202 applied as a transimpedance photodiode is illuminated, the current must come from the amplifier (TIA). The LT6202 forces the BF862 ultralow-noise LT6202’s output through R1 and R2, as in a normal TIA. JFET source to 0V, with R3 ensuring that the JFET has an Amplifier input noise density and gain-bandwidth product I were measured at 2.4nV/Hz and 100MHz, respectively. DRAIN of 1mA. The JFET acts as a source follower, buffering the input of the LT6202 and making it suitable for the high Note that because the JFET has a high gm, approximately impedance feedback elements R1 and R2. The BF862 has 1/80Ω, its attenuation looking into R3 is only about 2%. a minimum I Gain-bandwidth product was measured at 100MHz and DSS of 10mA and a pinchoff voltage between –0.3V and –1.2V. The JFET gate and the LT6202 output the closed-loop bandwidth using a 3pF photodiode was approximately 1.4MHz. V + S R1 R2 499k 499k
Precision Low Noise, Low Power, 1MΩ Photodiode Transimpedance Amplifier
PHILIPS Figure 4 shows the LT6202 applied as a transimpedance BF862 C1 amplifier (TIA), very similar to that shown in Figure 3. – 1pF In this case, however, the JFET is not allowed to dictate V – BIAS LT6202 VOUT the DC-bias conditions. Rather than being grounded, the + LT6202’s noninverting input is driven by the LTC2050 to the exact state necessary for zero JFET gate voltage. The R3 4.99k noise performance is nearly identical to that of the circuit VS = ±5V in Figure 3, with the additional benefit of excellent DC per- V – LT6202/03/04 F03 S formance. Input offset was measured at under 200µV and output noise was within 2mVP-P over a 20MHz bandwidth.
Figure 3. Low Noise, Low Power 1M
Ω
AC Photodiode Transimpedance Amplifier
V + S R1 R2 499k 499k PHILIPS C2 BF862 R4 C1 0.1µF 10M 1pF – V – BIAS – R5 LT6202 VOUT 10k + LTC2050HV + C3 1µF R3 4.99k VS = ±5V V – S LT6202/03/04 F04
Figure 4. Precision Low Noise, Low Power Transimpedance Amplifier
620234fd 20 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Applications Information Typical Applications Package Description Revision History Typical Application Related Parts