English
Language : 

QT9701B Datasheet, PDF (2/28 Pages) Quantum Research Group – CHARGE - TRANSFER CAPACITANCE SENSOR IC
  29(59,(:
7KH 47% LPSOHPHQWV DOO FKDUJHWUDQVIHU 47 FRQWURO DQG
VLJQDO SURFHVVLQJ IXQFWLRQV QHFHVVDU\ WR PDNH D KLJKO\
VHQVLWLYH DQG VWDEOH FDSDFLWDQFH VHQVRU 2QO\ D IHZ ORZ FRVW
H[WHUQDO SDUWV DUH UHTXLUHG WR PDNH WKH XQLW IXOO\ IXQFWLRQDO
WKHVH FDQ EH UHDGLO\ VHOHFWHG IRU D VSHFLILF UDQJH RI
FDSDFLWDQFH GHWHFWLRQ
$ EORFN GLDJUDP RI WKH 47% KDUGZDUH LV VKRZQ LQ )LJXUH
 )LJXUH  VKRZV D W\SLFDO VHQVRU FLUFXLW HPSOR\LQJ WKH ,&
VHH DOVR )LJV   
 10B82 >?4A0C8>=
7KH 47% LV D EXUVW PRGH 47 FRQWUROOHU 47 F\FOHV DUH
H[HFXWHG YLD EXUVWV RI SXOVHV RQ FRQWURO OLQHV &+* DQG ;)5
&65 LV SURYLGHG WR UHVHW WKH FKDUJH GHWHFWLRQ FDSDFLWRU &V
DQG OLQH 603 LV SURYLGHG WR SHUPLW DQDORJ VDPSOLQJ RI WKH
DPSOLILHU VLJQDO WR FUHDWH D GLUHFW DQDORJ RXWSXW LI GHVLUHG
7KH QXPEHU RI SXOVHV LQ HDFK EXUVW LV FRQWUROODEOH YLD HSURP
RU LQ WKH DEVHQFH RI DQ HSURP LV VHW WR  SHU EXUVW 7LPLQJ
LQIRUPDWLRQ LV IRXQG LQ )LJXUH 
:LWK HDFK ;)5 FRQWURO SXOVH FKDUJH DFFXPXODWHV RQ FDS &V
7KH PRUH WUDQVIHU SXOVHV ZLWKLQ D EXUVW WKH KLJKHU WKH JDLQ
EXW DOVR WKH KLJKHU WKH DFFXPXODWLRQ RI FKDUJH GXH WR VWUD\ &
0RUH WUDQVIHU SXOVHV DOVR SURGXFH DQ DYHUDJLQJ HIIHFW ZLWK &V
DFWLQJ DV DQ LQWHJUDWRU WR SURGXFH DQ DULWKPHWLF PHDQ RI DOO
FKDUJH DFFXPXODWHG ZLWKLQ D EXUVW 7KH YROWDJH RQ &V PD\
EHFRPH ODUJH HQRXJK WR SURGXFH VLJQLILFDQW QRQOLQHDULWLHV DQG
FDXVH PRVIHW 4 EDFNGLRGH UHYHUVH FRQGXFWLRQ FKDUJH
FDQFHOODWLRQ PHWKRGV DUH XVHG WR µEXFN¶ WKH DFFXPXODWLRQ RI
FKDUJH RQ &V DV GHVFULEHG EHORZ
$W WKH HQG RI HDFK EXUVW WKH DPSOLILHG VLJQDO IURP &V LV
FRQYHUWHG WR GLJLWDO LQ WKH 47% DQG IXUWKHU SURFHVVHG
,QWHUQDOO\ WKH ,& FRQWDLQV VHYHUDO VHOHFWDEOH SURFHVVLQJ SDWKV
ZKLFK PD\ EH HPSOR\HG WR ILOWHU QRLVH FRPSHQVDWH IRU VLJQDO
GULIW DQG FUHDWH GLIIHUHQW VHQVLQJ HIIHFWV 6HH 6HFWLRQ  IRU
PRUH GHWDLOV RQ VLJQDO SURFHVVLQJ
7KH VHQVRU DOVR SURYLGHV D 67$7 SLQ ZKLFK DFWV WR LQGLFDWH WKH
FXUUHQW VWDWH RI WKH VHQVRU DQG DQ DFWLYHKLJK 287 SLQ ZKLFK
SURYLGHV WKH SULPDU\ RXWSXW ZKHQ WKH VLJQDO UHDFKHV D
SUHGHILQHG FULWHULD VXFK DV H[FHHGLQJ D VSHFLILHG VLJQDO OHYHO
! 102:6A>D=3 2g BD??A4BB8>=
6WUD\ EDFNJURXQG µ&[¶ LV DQ H[WUHPHO\ LPSRUWDQW IDFWRU LQ PDQ\
)LJXUH  %ORFN 'LDJUDP
9''
2XWSXW
6WDWXV
%*
2%-
,2
'5,9(56
6,*1$/
352&(6625
47 '5,9(
6(48(1&(5
FKDUJH
WUDQVIHU
&V UHVHW
EXFN 
EXFN 
EXFN 
EXFN 
VDPSOH
&+*
;)5
&65
=
=
=
=
603
'$
;7
;7
26&,//$725
%8))(56
'$
$'&
6(5,$/
((3520
,17(5)$&(
(&6
$,1
)LJXUH  +LJK *DLQ &LUFXLW
9FF
2XWSXW
91
4


 287 9'' 9'' &+* 
 966
 966
8
;)5 
9XQUHJ

/('
5
47
&65 
= 
4
91
 67$7
= 
9FF
= 
= 
5 5
$,1 
 %*
%*
2%-
 2%-
;7
;
 ;7
7(50,1$/
5(621$725
(&6

 0+=
'$ 
'$ 
'$ 
'$ 
'$ 
'$ 
'$ 
'$ 
603


&6

8
'2 
((3520 ', 

/&
RSWLRQDO
6. 

9FF
S)
&] V DUH RSWLRQDO
&]
&]
5 5
&]
&]









5
5V

4
%61$
6HQVH
&V
 9FF
8
&V Q)
&][ Q) HDFK
5
7/&
5 5

5
8
,2
DQDORJ RXWSXW
FLUFXLW RSWLRQDO
,2
*
8
&
S)
VHQVRU V\VWHPV )RU H[DPSOH DQ DWWHPSW WR FRQYH\
WKH FDSDFLWDQFH HIIHFW WR D UHPRWH REMHFW RIWHQ
UHTXLUHV D VKLHOGHG FDEOH ZKLFK ZLOO DGG DQ RIIVHW
FDSDFLWDQFH 7KHUH DUH PDQ\ RWKHU SRVVLEOH
VRXUFHV RI VXFK ORDGLQJ IRU H[DPSOH WKH HOHFWURGH
LWVHOI ZKLFK PD\ EH LQ FORVH SUR[LPLW\ ZLWK DQRWKHU
VXUIDFH ,Q PRVW FDVHV EDFNJURXQG µ&[¶ LV YDVWO\
JUHDWHU WKDQ WKH VLJQDO WR EH REVHUYHG DQG ZLWKRXW
VRPH FRPSHQVDWLQJ PHFKDQLVP FDQ VZDPS WKH
VHQVRU
$V GHWDLOHG DOVR LQ GRFXPHQWDWLRQ FRQWDLQHG LQ WKH
43UR[ (6 PDQXDO WKH 47% HPSOR\V WZR
VWUDWHJLHV IRU VXSSUHVVLQJ EDFNJURXQG &
" 2i 270A64 20=24;;0C8>=
7KH ILUVW PHWKRG RI FKDUJH FDQFHOODWLRQ LQYROYHV WKH
XVH RI H[WHUQDO FDSDFLWRUV &] WKURXJK &] DQG
FRUUHVSRQGLQJ ,& SLQV = WKURXJK = 1RUPDOO\
== DUH KHOG WR 9&& ZKLOH &65 FODPSV &V WR
JURXQG 'XULQJ WKH FRXUVH RI D EXUVW &65 LV
UHOHDVHG DQG RQH RU PRUH RI OLQHV == PD\ EH
GULYHQ WR JURXQG LQ VHTXHQFH (DFK EXUVW LV
FRPSRVHG RI  µVXEEXUVWV¶ DV VKRZQ LQ )LJXUH 
LI WKH FKDUJH WKDW DFFXPXODWHV RQ &V LV ODUJHU WKDQ
DERXW  YROWV RQH RI WKH == OLQHV ZLOO
WUDQVLWLRQ GRZQ WR SURYLGH D FKDUJH FDQFHOODWLRQ