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标题: CC2530-RBIAS 电阻值设置为多少依据是什么? [打印本页]
作者: 鸣涧_GC96O 时间: 2021-4-1 15:18
标题: CC2530-RBIAS 电阻值设置为多少依据是什么?
CC2530-RBIAS 电阻值设置为多少依据是什么?
datasheet描述为
| RBIAS | 30 | Analog I/O | External precision bias resistor for reference current |
设置参考电流(bias resistor for reference currentreference current),,设置什么的参考电流呢?! Q. x; Q W d* a+ u8 y) q+ r
电阻值对应的参考电流,计算方法是什么呢? 请帮忙详细说明一下6 r8 n; _3 W7 S0 ` `
参考设计设置是56K, why? 如果是要固定56k, 为什么不在芯片里固化呢?
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作者: sunsili 时间: 2022-1-12 23:48
为什么连TI知名品牌资料，都没详细说明呢？
作者: sunsili 时间: 2022-1-12 23:53
TI官方论坛里也有问了这个问题
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RBIAS uses external resistor for internal biasing. Value in datasheet is mentioned to be 56kOhm and in application notes it is mentioned that precision resistor is required. Anyhow it is not mentioned that what tolerance is acceptable for RBIAS as using 56k resistor only for this purpose would be new part number for design and manufacturing while there would be e.g. already 56.2k used elsewhere.
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! [. D& f3 ]* n回复如下：' z# ^6 \) k" d; K8 ]- g- {- Y
Hello Janne,) J: o& } A% j) h6 O; @
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The recommended tolerance on 56K bias resistor for CC2530 is ±1%.5 |9 |- A$ _8 e9 g. p7 _
7 J4 j' }3 p7 yRegards,2 Z: A- |4 [/ E( H
9 o4 e- w2 Q, Y6 }4 K, g也是详细说明，why 56k
作者: sunsili 时间: 2022-1-12 23:55
Why the RBIAS pin of the CC2530 should be connected to a 56K resistor？Why？I am crazy，HELP！
2 H1 v& h3 Z: JOther Parts Discussed in Thread: CC2530Why the RBIAS pin of the CC2530 should be connected to a 56K resistor？Why？
9 Q1 F) ]! o6 p- ]- p. II know a base current is affected to the bias resistor，but which unit use the current？* _1 l/ a9 M0 H8 o
ADC？DAC？RF？Amplifier？Comparator？
, B& S& f% ^* K( w' a0 XWhy it is 56K，and ±1%，if not，what problem can be happen？2 }/ U+ Q$ ^- R: X( k8 b0 m
when use 47K or 62K，what probelm can be happen？1 _3 k7 G" [; X3 `: \( a
who can tell me？
8 G; n2 V$ x- d) _: wI‘m crazy！！！
- Y0 |8 b1 W" W- kHELP！
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TI回复：
2 e8 u; ]' B0 ~Hi,
3 n& H; y, S" CThe RBIAS on all of our CC devices is used by an internal current source to setup a reference for the all analog circuits inside the device. If you change the value that we recommend the chip might not work at all. You need to use a 1% resistor and the value we use on that location. Furthermore you need to make sure there are no noise sources close to it as it will negatively influence the entire chip performance.
. G9 C7 W- }7 k" b( X RI would kindly recommend, next time you generate a post on this forum, to keep the discussion and the wording on purely technical terms and subjects.
1 C9 p/ ] ~) x8 I/ k4 w# l3 l7 j9 UThe use of certain sentences may discourage people in the e2e community from helping you.
. d3 B6 N4 w& a8 G1 EThanks for your understanding.
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作者: sunsili 时间: 2022-1-13 00:02
TI官方论坛有同样的问题：
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CC2530-RBIAS 电阻值设置为多少依据是什么? & l3 ]! O3 X! a1 d6 s
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CC2530-RBIAS 电阻值设置为多少依据是什么? t5 `7 ^3 L! f: \2 L0 Y
datasheet描述为
# w5 [( q! x, A9 L1 [% x* R" b% e/ _| RBIAS | 30 | Analog I/O | External precision bias resistor for reference current |
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设置参考电流(bias resistor for reference currentreference current),,设置什么的参考电流呢?
. U/ G. t Q# f3 X2 g 电阻值对应的参考电流,计算方法是什么呢? 请帮忙详细说明一下
. l. b* k& W [7 l$ p参考设计设置是56K, why? 如果是要固定56k, 为什么不在芯片里固化呢?6 Y& k5 v; H* ?1 R( Z4 e
+ X- F1 s. p2 e$ O! V: ]& aTI回复及追问： ( V: P" F/ r4 c8 N& j* E7 \- b
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- 类似电压电流的偏置，如果精度或者阻值有变化会对内部电压和电流都造成影响，芯片内部精度达不到
- ]3 T- ^; p. w不需要计算，值是固定的56K，容差1％+ \ r- R+ h% i7 R
e2e.ti.com/.../2896984
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- _7 t$ H# [, N+ s; w3 g- i6 }4 Q追问： 还是没有明白, 如何设置RBIAS 电阻值, 电阻值对应的参考电流,计算方法是什么?请帮忙详细说明一下# D; \7 J. j' ^3 Z) j" |
" n5 J8 k" e2 J4 J8 r7 n( r) [/ Y TI回复： 这个值设计芯片时已经固定了，不能更改，用户只需要按数据手册中的规定使用就行了
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& a1 H: J8 S/ O; f; q0 K0 \ 追问： 数据手册, 什么都没写?+ ^: k$ ?2 s1 Z( ?) u
datasheet描述为, Q }: l) W; Z6 \% d
5 [5 z' V" R! U* R9 @1 A8 [9 YRBIAS 30 Analog I/O External precision bias resistor for reference current
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我想详细了解一下,如何设置RBIAS 电阻值, 电阻值对应的参考电流,计算方法是什么?设置参考电流(bias resistor for reference currentreference current),,设置什么的参考电流呢?请帮忙详细说明一下. ^) }7 A1 ?3 q1 C; t6 S' P4 O
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TI回复： -
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手册中说明了具体阻值
, X( h, V* d5 O. d9 L; t4 D: q: W用户只需要按要求使用规定的电阻就行了
) |0 s+ f! A4 Z; F: y! X# V至于计算方法和具体细节，这是芯片设计部分的问题，我无法对此做出更多评论( c+ A0 Y j5 {: M4 p5 L: r& o
' I5 j+ n. X- E" K. x' O; T最终结论： - 无解，按规定用56K电阻, no why, 难怪老外会 crazzy
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作者: 鸣涧 时间: 2022-3-22 23:52
谢谢回复，有点明白
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