General transimpedance design
Defenetly look at freely availabe chapter X of art of electronics in particular at
Good references can be found in TI application notes
- transimpedance amplifier design from TI sboa122.pdf more detailed note
- transimpedance amplifier choice from TI snoa942a.pdf less details
ASPECT: Adding/Subtracting Photo-Electric Circuit with Transimpedance
ASPECT v1.0 implementations
In the spring of 2019, Alex Fay was in charge of redisigning the balance photodiode circuit to add additional capabilities to see each channel separately as well as sum and difference.
The board was designed with kiCad and will require the custom library
QOL-KiCadRev2.zip Schematic of v1.16 (note that v1.12 was actually sent to the board house)
ASPECT v1.16.zip. This boards manufactured by Imagineering Inc. http://PCBnet.com in april 2019. Excellent quality, quick turn around (2 weeks with delivery time), very reasonable price $300 for 25 boards.
Have a look at elog entry to see the most up-to-date schematics with notes for a particular implimentation with OPA27 and Thorlabs Photodiodes FDS100.
It make sense to look through elog to see glitches or corrections to this board.
Original simple balanced photodiode
Design is based on the Chris Wipf schematic done at MIT.
Here is initial schematic local pdf, also external link to Wipf's pdf
This is our own Eagle files with schematic and board layout, as well as GERBER files generated from them. We already have several revisions:
- bpd v1.zip. This archive was sent to http://pcbexpress.com for fabrication.
- BPD v2 1.5x2in.zip. This archive was sent to http://pcbexpress.com for fabrication on 20070316.
- BPD v3 1.75x3in.zip.
- BPD v4 1.75x3in.zip. This boards manufactured by Imagineering Inc. http://PCBnet.com in may 2013. Excellent quality, quick turn around (2 weeks with delivery time), very reasonable price $200 for 20 boards.
Hard lesson from practice
What ever you do keep feedback traces short, and free of ground plane underneath.
Eugeniy's current favorite for the first stage is ADA4817: very low noise and fast GBW = 1 GHz amplifier. If speed is not that important the OPA27 and OPA37 are very good too, smaller or comparable noise to ADA4817, but GBW almost a factor smaller. When battery longevity is of importance remember that ADA4817 consumes 20 mA of quiescent power while OPA27/37 only about 5mA.
ADA4817 datasheet have formulas for recommended feedback capacitor size. I find that I generally need to have a bit larger values when very small value recommended 1pF ->2pF.
Prior 2013 observations
- I decided to use OPA842ID (details from Texas Instruments) instead OPA847ID. Main reason it is stable at unity gain (for the price of lowered gain BW product). But at least it does not ring at 600 MHz for unknown reasons.
- R3 (shunt) can be replaced with a short
- no need to install C1 (unless low pass filter is needed)
- C5 (feed back capacitor) must be equal or slightly larger of 9 pF for use with feedback resistor R1=1kOm and Hamamatsu PD S5106 with internal capacitance of about 50 pF at 5V reversed bias. Otherwise circuit oscillate at about 24 MHz when connected to 1 MOm load resistor (scope) at 50 Om load it stable even without feedback capacitor.
- R2 (ground to positive shunt resistor of 1 kOm is not really needed, but without it circuit showed offset of about 20 mV.
- note: offset can be killed without noise increase by putting capacitor of 100nF and above parallel to R2
Integrated circuits used in early BPD assembly
- Operational Amplifier OPA847 (specifically OPA847ID) Texas Instruments, specifications:
- Terminal Adjustable Negative Regulator LM337 (specifically LM337T) National Semiconductors, specifications:
- 5 Amp Adjustable Regulator LM338 (specifically LM338T) National Semiconductors, specification:
- local copy
- NS pdf ?NewArk components for BPD without 2.5pF capacitor (everything for BPD part, not including voltage stabilization):
Some links to the parts used in assembly
Pay special attention to TYCO connectors which are used in assembly
| Newark Part # | Qty | Product Description | Manufacturer Part # | List Price |
|---|---|---|---|---|
| 85C1047 | 10 | Multipole Connector; Number of Contacts:3; Gender:Female; Body Material:Nylon; Series:CST-100; Color:White; Connecting Termination:Crimp; Leaded Process Compatible:Yes; Wire Size (AWG):26-22; Diameter:0.320in RoHS Compliant: Yes | TYCO ELECTRONICS / AMP - 1375820-3 | 0.191 |
| 85C1053 | 30 | Multipole Connector; Body Material:Tin Plated; Series:CST-100; Connecting Termination:Crimp; Leaded Process Compatible:Yes RoHS Compliant: Yes | TYCO ELECTRONICS / AMP - 1445336-1 | 0.067 |
| 90F4251 | 10 | Wire To Board Header; Number of Contacts:3; Pitch Spacing:0.100"; Gender:Header; Number of Rows:1; Contact Finish:Tin; Leaded Process Compatible:Yes; Mounting Type:Through Hole; Peak Reflow Compatible (260 C):No RoHS Compliant: Yes | TYCO ELECTRONICS / AMP - 640456-3 | 0.156 |
| 53K1907 | 10 | Thick Film Resistor; Series:CRCW; Resistance:10kOhm; Resistance Tolerance:+/- 1 %; Power Rating:0.25W; Voltage Rating:200V; Temperature Coefficient:+/-100 ppm; Package/Case:1206; Leaded Process Compatible:Yes RoHS Compliant: Yes | VISHAY DALE - CRCW1206 10K 1% 100 ET1 | 0.108 |
| 53K1779 | 10 | Thick Film Resistor; Series:CRCW; Resistance:1kOhm; Resistance Tolerance:+/- 1 %; Power Rating:0.25W; Voltage Rating:200V; Temperature Coefficient:+/-100 ppm; Package/Case:1206; Leaded Process Compatible:Yes RoHS Compliant: Yes | VISHAY DALE - CRCW1206 1K 1% 100 ET1 | 0.108 |
| 57K1831 | 10 | Tantalum Capacitor; Capacitance:6.8uF; Capacitance Tolerance:+/- 10 %; Working Voltage DC:25V; Package/Case:3528-21; Terminal Type:PCB Surface Mount; ESR:2.8Ohm; Leaded Process Compatible:Yes; Operating Temp. Max:85 C RoHS Compliant: Yes; | KEMET - T491B685K025AT | 0.465 |
| 57K1618 | 10 | Tantalum Capacitor; Capacitance:0.1uF; Capacitance Tolerance:+/- 10 %; Working Voltage DC:35V; Package/Case:3216-18; Terminal Type:PCB Surface Mount; ESR:20Ohm; Leaded Process Compatible:Yes; Operating Temp. Max:85 C RoHS Compliant: Yes; | KEMET - T491A104K035AT | 0.167 |