4127 BURR-BROWN | Alldatasheet
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For Immediate Assistance, Contact Your Local Salesperson BURR-BRO ie 4127 FEATURES current and four decades of input voltage. In addition, a current inverter and a precise internal reference @ ACCEPTS INPUT VOLTAGES OR allow pin programming of the 4127 as a logarithmic, CURRENTS OF EITHER POLARITY log ratio, or antilog amplifier. @ WIDE INPUT DYNAMIC RANGE To further increase its versatility and reduce your
6 Decades of Current system cost, the 4127 has an uncommitted operational
4 Decades of Voltage amplifier in its package that can be used as a buffer,
@ VERSATILE inverter, filter, or gain element. Log, Antilog, and Log Ratio Capability ‘The 4127 is available with initial accuracies (log conformity) of 0.5% and 1.0%, and operates over an ambient temperature range of 10°C to +70°C. DESCRIPTION With its versatility and high performance, the 4127 Packaged in a ceramic double wide DIP, the 4127 is has many applications in signal compression, trans- the first hybrid logarithmic amplifier that accepts ducer linearization, and phototube buffering. signals of either polarity from current or voltage Manufacturers of medical equipment, analytical sources. A special purpose monolithic chip, devel- instruments, and process control instrumentation will ‘oped specifically for logarithmic conversions, find the 4127 a low cost solution to many signal functions accurately for up to six decades of input —_ processing problems. boo neennneeceedenecceceeecneesececeeeeneneecceneeeed HBVDG Sc1svo0 @@ 1731365 O0e8b7b OFT International Apr Indust Park + aling Adress; PO Box 11400 Tucaon, AZSTS4 + Shout Ades: 67308. Tucson Bid.» Tucson AZ 85705 "Tan(6Z) 7064111 + Twr 9100524111 + Cable: BBRCORP + Telex: 086461 - FAX:(612) 850-1510 + Immediate Producto (8) 56152
7.102 PDS-46F (=123
Or, Call Customer Service at 1-800-548-6132 (USA Only) ELECTRICAL Top View Tyla! Speccaton at +25°C with rated suplis, unless otherwise noted, a tee Ouput [7 | [26] No en Present ACCURACY, of FSA Current Sour Input: 1A to mA 1% max ‘heros [2 | [23 | eas Voltage Input: imV 10 10¥ 4% max No Pa Prosort| 3 | Postive Supply INPUT i Curent Soure Input Pn Ana ima stirout[4 | [21 } common Curent Sours Ing. Pe 7 “ina to “ima sn n " Falrence Cone! Wout Pe 2 peiregey Caran arr Ov” 5 | [z2] Noe pect Absolute Maximum Inputs #10mA or +Supply Vorts No Pin Present | 6 | [19] Gain Adjust Votage s10v Current vert Input [16] tog ouput Current saa No Pin Prosont| 8 | [17 ] No Pin Present FREQUENCY RESPONSE Opn» + nou 9 | [16] No Pin Presone
848 Small Signal at Curant Input Op Amp ~input [10] [15] No Pn Present
ot Oya pati op Amp Outpt [17] [14] Negatve Supey ofA ‘re of 10004 ee No Pn Presont | 12] [ia ]nc at ion one SfralVave t= AACS tons NOTE: (1 Pins 4 and 6 ar renal connected STABLY Scale Fac Ot (44°C) 20.0006A°C Reternce Cure rit (ay) £9001 YC for 2 WA #0.003 19°C for 400nA < |, < 1pA Input Ofset Curent Orit Aly") | rapa at 125°C, Doubs Every 10°C Input Offset Votage Drift 410K PACKAGE INFORMATION” KR ‘Supply Vanaon Input Offset Voltage +£300uV/V NUMBER ad Input Nose» Curent Input 1A ms, 12 10H w127KG 26 in O75 +t Input Nowe» Vatago treat 301A, ey OH Yo TONE ize 209i os ‘UNCONMITTED OP AMP CHARACTERISTICS NOTE: (1) For dialed drawing and doncion table, posse ave end of cara Input Otfset Voltage smv ‘sheet, or Appendix D of Bur-Brown IC Data Book. 7 Input Bas Curent fama ‘Input impedance MQ. Goo Signal Vetage Gain esas o Output Current SmA z TEMPERATURE RANGE 6 Spectcaton 70 wo +800 fe) Operating toc te #700 E Storaee “ow a5 5 POWER SUPPLY REQUIREWE) z Fated Suply Votages s19v00 s Supp) Vouage Range +#14V06 te st6v06 Supply Coron Oran im at Quiescent, max 220mA, a at Ful Load, mae an z NOTE: (1) Log contormty at 25°6 5 a The ilomaton provided heron i beloved to bo reais; however, BURF-BROWN assumes no responsbily for inaccuracies or omissions. BURA-SROWN asus no rosponsibity for he use fs infomation anda seo such normaton salle ently at the user's own nic roe and epocoatone ee cose to change winout noice. No patent gh or learse i any of he ccuts deserted era ate mplod ox granted dry hee pat, GUAR BRWN soos et authorize or warant any BURR-BROWN orodct for use in Mo support devon anor sym — M@ 1731365 0028677 Tab mm
For Immediate Assistance, Contact Your Local Salesperson TYPICAL PERFORMANCE CURVES ‘At 425°C with rated supplies, unless otherwise noted. RELATIONSHIP OF REFERENCE CURRENT, ly, RELATIONSHIP OF SCALE FACTOR “A” {AND EXTERNAL RESISTOR. R, TO GAN SETTING RESISTOR. Ry “oun N ‘ ; |. | -- be | A 10d — S7 K+ -- 1 a a i. lo —_ 10008 - | 2 == a hand eon toma ol freely 1S iow 00M 0 2 ~ =o Resistance (2) Resistance (2) Loe nevaTionsie oF "él ano oureur revarionsi oF {! ano ourpuT VOLTAGE VOLTAGE IN TERMS OF 2° For qs WA and A BV and 10¥ Freee tal Senaad ts /otage Foe Abele Votage Eo =-Abog 44) &6-Volis tov A=10V . i Input bo 0 Canon oe Conrert th . ls Got oot ot WN 100 1000 OHA GAYA WK TOUA 1005 ho hh fate Vv ange ot * | om ov 100 4A = 008 | DISCUSSION OF SPECIFICATIONS ACCURACY STABILITY The deviation from the ideal output voltage defined as a ‘The use of a monolithic transistor quad and low-drift amps percent of the full scale output voltage. minimizes drift, but some drift remains in the scale-factor, reference current, and input offset. Input offset consists of a INPUTIOUTPUT RANGE E Feel ee ane Ate, tt one ska deta ' 5 signal source resistance. Also, there is some slight dri ‘The log relationships of ~A log —~ and -A log 2 a in conformity to the log function and in output amplifier subject to the constraints specified. The 4127 can be oper- “1/84 but this is generally negligible. ated with inputs lower than those given, but the accuracy will be degraded. THEORY OF OPERATION The 4127 is a complete logarithmic amplifier that can be FREQUENCY RESPONSE . . pin-programmed to accept input currents or voltages of ‘The small-signal frequency response varies considerably either polarity. By making use of the internal current in- with signal level and scaling, so the frequency response is verter, reference current generator, log ratio element, and specified under several different operating conditions. uncommitted op amp, you can generate a variety of logarith- M@@ 1731365 0028678 912 a Burr -prowne
7.104 Burr-Brown IC Data Book—Linear Products
Figure 1. In addition to the basic log amplifier, the 4127 to electrostatic pickup. The outpu de evidos a voitg .
8 OpAmp <
FIGURE 1. Functinal Diagram.
ships are shown in Typical Performance Curves. reference current (see Figure 2). FIGURE 2. Transfer Function When I, is Positive, ea 3. Apply ty! = Iyaxs adjust R, for the proper output voltage. 10 =A log Tieslen 4, Repeat steps 2 and 3 if necessary. A that will provide a full +10V output swing are: output voltage. For R,, a single resistor is recommended. Ta = Tax Shaw and A Th amplifier offset voltage. This is an 804B range. reference current (see Figure 3).
7.106 Burr-Brown IC Data Book—Linear Products
vevooe pareve 4, Apply E, = Eyqu, adjust R, for the proper output.
- Repeat steps 2 through 4 if necessary.
a EP Poe internal reference current (see Figure 5).
10 Curent, 2 in beg,
FIGURE 3. Transfer Function When I, is Negative. A Sn
- Refer to Choosing the Optimum Scale Factor and Refer- 100Me
- Apply Ij! = I, adjust R, such that E, = 0. wsvoo YR, -15v0C
- Apply Il,! = Iyqx» adjust R, for the proper output voltage tora
- Ignore this step if Iya! 2 10nA. Otherwise, apply Il,| =
RA, 4. Apply IE,! = Exqy, adjust R, for the proper output. FIGURE 4. Transfer Function When E, is Positive. Ohne
- Refer to Choosing the Optimum Scale Factor and * ao
- Apply E, = Ip (10K), adjust R, such that Ep = 0. FIGURE 6. Transfer Function When I, and I, are Negative.
- Apply E, = Exax, adjust R, for the proper output voltage.
- Refer to Choosing the Optimum Scale Factor and replace R,.
- No further adjustment is necessary if I, ya 2 10nA, s5v0C0 © -15v0e
L FIGURE 8. Transfer Function When I, and I, is Positive. =o Re NOTE: (1) Needed only 19 as shown in Figure 9. FIGURE 7. Transfer Function When I, is Negative, I, is Pet. en le = Jar |e &
- Refer to Choosing the Optimum Scale Factor and a
- No further adjustment is necessary if Hho 2 10nA, Insert 0.01pF betweon
replace Ry, FIGURE 9. Antilog Operation.
- No further adjustment is necessary if I, ay 2 10nA, om
7.108 Burr-Brown IC Data Book—Linear Products
Or, Call Customer Service at 1-800-548-6132 (USA Only) ‘Combining expressions for E, gives the relationship: Rr __ mkT Ey Rama Ry Es = top Fo - 5 2 tog Fe A Roly where: ASR (a6myy— R; 0.434 Ey= Ro I, Antilog - = Setting Ry and I, will set the scale factor. For example, an Ry of IMQ and I, of IPA will give a scale factor of unity = Antilog - 2 and Ey = Antilog ~ == n nN e t wn z fe) E oO z ire a Ww o n yeeerowy MM 1731365 0028683 28T Burr-Brown IC Data Book—Linear Products 7.109