一、數字電位器芯片有哪些
數字(zi)(zi)(zi)電(dian)(dian)(dian)(dian)位(wei)器(qi)(DigitalPotenTIometer)亦稱數控可編程電(dian)(dian)(dian)(dian)阻器(qi),是一(yi)種(zhong)代替傳統機械(xie)電(dian)(dian)(dian)(dian)位(wei)器(qi)(模(mo)擬(ni)電(dian)(dian)(dian)(dian)位(wei)器(qi))的(de)(de)新(xin)型(xing)CMOS數字(zi)(zi)(zi)、模(mo)擬(ni)混合(he)信號處(chu)理(li)的(de)(de)集成電(dian)(dian)(dian)(dian)路。數字(zi)(zi)(zi)電(dian)(dian)(dian)(dian)位(wei)器(qi)由數字(zi)(zi)(zi)輸(shu)入控制,產(chan)生一(yi)個(ge)模(mo)擬(ni)量(liang)的(de)(de)輸(shu)出(chu)。依據數字(zi)(zi)(zi)電(dian)(dian)(dian)(dian)位(wei)器(qi)的(de)(de)不(bu)同(tong),抽頭(tou)電(dian)(dian)(dian)(dian)流最大值可以從幾(ji)(ji)百微安(an)到(dao)幾(ji)(ji)個(ge)毫(hao)安(an)。下面介紹幾(ji)(ji)種(zhong)常用數字(zi)(zi)(zi)電(dian)(dian)(dian)(dian)位(wei)器(qi)芯片(pian):
1、數字電位器MAX5432/5433
MAX5432/5433的(de)(de)端(duan)(duan)到(dao)端(duan)(duan)電阻(zu)(zu)分別為50kΩ及100kΩ,端(duan)(duan)到(dao)端(duan)(duan)的(de)(de)電阻(zu)(zu)溫度(du)系數(shu)(shu)標稱值為35ppm/℃,比例溫度(du)系數(shu)(shu)只(zhi)有5ppm/℃,可應(ying)用于(yu)需要低溫度(du)系數(shu)(shu)可變(bian)電阻(zu)(zu)的(de)(de)電路中,例如低漂移、可編程增益放大(da)器電路。芯(xin)片采用8引腳(jiao)TDFN封(feng)裝,具有一個散熱功(gong)能(neng)的(de)(de)接地焊接點EP,將該點焊接在具有適當面積的(de)(de)印(yin)板銅皮上,使芯(xin)片可工作在-40℃:至+85℃擴展級溫度(du)范圍。
2、數字電位器MAX5438
MAX5438是MAXIM公司生產的(de)(de)(de)7位(wei)(wei)128階(jie)數(shu)字(zi)電(dian)(dian)位(wei)(wei)器。它由(you)1個7位(wei)(wei)移位(wei)(wei)寄存(cun)(cun)器,1個7位(wei)(wei)數(shu)據(ju)鎖(suo)存(cun)(cun)器,模塊,電(dian)(dian)位(wei)(wei)器和控制(zhi)時(shi)鐘邏輯組成。MAX5438的(de)(de)(de)控制(zhi)信(xin)號(hao)包括3個輸入(ru)(ru)信(xin)號(hao):芯(xin)片選擇(/CS),數(shu)據(ju)輸入(ru)(ru)(DIN)和串行時(shi)鐘(SCLK),數(shu)字(zi)邏輯由(you)一(yi)個2.7V~5.25V的(de)(de)(de)電(dian)(dian)壓(ya)驅動(dong)。其內部電(dian)(dian)阻(zu)兩端的(de)(de)(de)電(dian)(dian)壓(ya)由(you)外(wai)部通過VDD及VSS提供(gong),VDD與VSS之間的(de)(de)(de)電(dian)(dian)壓(ya)必須大于9V小(xiao)于31.5V。這使(shi)得(de)MAX5838在輸入(ru)(ru)電(dian)(dian)壓(ya)的(de)(de)(de)選擇上具有(you)很(hen)大的(de)(de)(de)靈活性。同時(shi),MAX5438的(de)(de)(de)外(wai)部電(dian)(dian)路非常(chang)簡單,幾(ji)乎不需要任(ren)何外(wai)接元件就可實(shi)現(xian)對(dui)輸入(ru)(ru)電(dian)(dian)壓(ya)的(de)(de)(de)調節輸出(chu)。
二、數字電位器芯片選型的要點有哪些
選(xuan)擇數(shu)字(zi)電(dian)(dian)位(wei)器芯片應考(kao)慮的(de)(de)(de)(de)方(fang)面很多,電(dian)(dian)位(wei)器的(de)(de)(de)(de)個數(shu),滑片的(de)(de)(de)(de)數(shu)目即(ji)有多少級(ji),電(dian)(dian)阻的(de)(de)(de)(de)阻值,有沒(mei)有緩沖觸頭(tou),能否記憶掉電(dian)(dian)時的(de)(de)(de)(de)位(wei)置(zhi),封裝等。相似(si)于3386電(dian)(dian)位(wei)器的(de)(de)(de)(de)封裝及特(te)點,總(zong)的(de)(de)(de)(de)來說數(shu)字(zi)電(dian)(dian)位(wei)器芯片選(xuan)型主要還(huan)是從以下三(san)點進(jin)行(xing)考(kao)慮。
1、數字電位器抽頭的變化形式:系統重新通電(dian)時,阻值能(neng)夠恢復上一次掉電(dian)時的阻值,則要選(xuan)擇(ze)非易失性的數字電(dian)位器。
2、數字電位器電壓:帶緩(huan)沖器輸(shu)出的(de)電位器,輸(shu)出是一個電壓值,而(er)不(bu)是一個電阻值,這時應該選擇(ze)不(bu)帶緩(huan)沖器的(de)。
3、數字電位器分辨率:如果系統對分(fen)辨率要(yao)求比較高,可選擇滑片數(shu)目多(duo)一些的(de)電位器(qi)(qi),或者(zhe)使(shi)用兩(liang)個數(shu)字電位器(qi)(qi)串聯達(da)到其目的(de)。