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原帖由 sd-iori 于 2008-3-4 17:34 发表
6 M2 {3 D3 _9 b& u, x8 s0 fTotal Harmonic Distortion
4 C4 L% V+ s& C# aTotal Harmonic Distortion + Noise (THD + N) of the OP275
I5 |% s1 b4 h% u' zis well below 0.001% with any load down to 600 W. However,
, M4 Q9 y3 z' G7 o# x) pthis is dependent upon the peak output swing. In Figure 2 it is
: R' x/ \4 S, y; P0 {0 _seen that the THD + Noise with 3 V rms output is below
" c5 e) k: [9 d% H4 s# P0.001%. In the following Figure 3, THD + Noise is below
+ t, d4 X, u+ @+ B0.001% for the 10 kW and 2 kW loads but increases to above
0 j0 L+ i5 \* D' F! n0.1% for the 600ÊW load condition. This is a result of the output
|* [' @! }! W6 n8 O6 pswing capability of the OP275. Notice the results in Figure 4,
) ^$ @; u1 G- ?# B# ~showing THD vs. VIN (V rms). This figure shows that the THD
7 P! k; ~+ Y* F3 V& `- J' k Q! {/ B+ Noise remains very low until the output reaches 9.5 volts rms.
( R- S8 V" m* o/ q' IThis performance is similar to competitive products.' c8 j) D" n; W, H* X4 P$ `
2 j2 z' \: f4 S i. |The output of the OP275 is designed to maintain low harmonic0 l# \2 l6 U5 H- B- ~
distortion while driving 600 W loads. However, driving 600 W
! L+ r" h- k, i3 y5 A; gloads with very high output swings results in higher distortion if/ Y& W- X+ o$ \; y, Z+ u
clipping occurs. A common example of this is in attempting to
9 {) Q: H( |# S1 s4 d9 Xdrive 10 V rms into any load with ±15 volt supplies. Clipping* U1 ~; F" d' `/ O( u
will occur and distortion will be very high. b _7 Y) t' u
To attain low harmonic distortion with large output swings,* W, u Z; W' M* s% X! n* I
supply voltages may be increased. Figure 5 shows the performance+ q% r9 x0 }, k0 K
of the OP275 driving 600ÊW loads with supply voltages, S6 b+ ~; G& D; a
varying from ±18 volts to ±20 volts. Notice that with ±18 volt
h0 Q4 Z2 e! ~+ i' e; hsupplies the distortion is fairly high, while with ±20 volt supplies
4 {. \5 a( g0 Q8 E! D& hit is a very low 0.0007%.
9 k. I0 C0 a# w7 m/ l: L: E9 ?6 d; Z: L1 C4 A* a) t
这是OP275 THD的说明,,
- X P3 ?( D Z$ s$ [大概意思是说,,3V,,THD为0.001,,, a- X2 W! M: ]* N! ?: X/ M
失真最少,,是20V以上,,,0.0007- d6 y: T6 z' H4 a
( g. u/ X1 d! A7 m
:charles: 不知,,有没有理解错误$ x% u+ w' H. j9 }: y2 G
) S% _9 \6 n' R) y$ h( P8 w
! t# {* R# ], M0 C" K7 F8 O' x: P5 z; J+ }
9 a, h6 P$ l# T" A ?
: G; |; p* @: [0 h; m- f3 n- T c3 E2 I8 R# U" y) @, S4 s, _
:sweatingbullets: 找不到12V下的,,数据,,
1 E% q2 Z3 H( q; E: B( U$ e; L1 S不过PDF,,里面,,也没有说列出电压对THD影响,,只是一味强调温度,,, H& e6 X8 [5 W- X- p4 F
从15V和18V的曲线看,,区别不大
, b; Y1 y+ n( p/ j/ E% aOP275对电压不敏感
/ u* N0 A5 b8 S7 M
$ }' Z2 p+ E8 W; ~' }[ 本帖最后由 sd-iori 于 2008-3-4 22:46 编辑 ] |
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