{"id":7836,"date":"2026-06-28T02:42:05","date_gmt":"2026-06-28T02:42:05","guid":{"rendered":"https:\/\/ic-vendor.com\/ht1621b\/"},"modified":"2026-06-28T10:20:27","modified_gmt":"2026-06-28T10:20:27","slug":"ht1621b","status":"publish","type":"post","link":"https:\/\/ic-vendor.com\/zh\/ht1621b\/","title":{"rendered":"HT1621B"},"content":{"rendered":"

\u4ea7\u54c1\u6982\u89c8<\/h2>\n

The HT1621B is a 128-pattern (32×4) RAM-mapping LCD driver controller from Holtek Semiconductor with 3-wire serial interface, built-in RC\/XT oscillator, watchdog timer, and buzzer output in a 48-pin SSOP\/LQFP package.<\/p>\n

\u4e3b\u8981\u89c4\u683c<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
LCD Pattern<\/td>\n128 (32×4)<\/td>\n<\/tr>\n
Display RAM<\/td>\n32 x 4 bits<\/td>\n<\/tr>\n
Bias Options<\/td>\n1\/2 or 1\/3 bias<\/td>\n<\/tr>\n
Duty Options<\/td>\n1\/2, 1\/3, or 1\/4 duty<\/td>\n<\/tr>\n
Operating Voltage<\/td>\n2.4V to 5.2V<\/td>\n<\/tr>\n
Interface<\/td>\n3-wire serial (CS, WR, DATA, RD)<\/td>\n<\/tr>\n
Built-in Oscillator<\/td>\n256kHz RC, supports 32.768kHz crystal<\/td>\n<\/tr>\n
Operating Current<\/td>\n100\u00b5A typical at 3V (LCD on)<\/td>\n<\/tr>\n
Standby Current<\/td>\n0.1\u00b5A typical at 3V<\/td>\n<\/tr>\n
Buzzer Frequencies<\/td>\n2kHz \/ 4kHz selectable<\/td>\n<\/tr>\n
WDT Overflow Output<\/td>\nYes (IRQ pin)<\/td>\n<\/tr>\n
\u5de5\u4f5c\u6e29\u5ea6<\/td>\n-40\u00b0C to +85\u00b0C<\/td>\n<\/tr>\n
\u5305\u88c5<\/td>\nSSOP-48 \/ LQFP-44<\/td>\n<\/tr>\n<\/table>\n

\u7279\u70b9<\/h2>\n
    \n
  • 32×4 bit display RAM directly maps to LCD segments<\/li>\n
  • Software-configurable bias and duty for LCD type compatibility<\/li>\n
  • 3-wire serial interface minimizes MCU pin count<\/li>\n
  • Built-in 256kHz RC oscillator or 32.768kHz crystal support<\/li>\n
  • Integrated watchdog timer with 8 selectable time bases<\/li>\n
  • Two selectable buzzer frequencies (2kHz\/4kHz)<\/li>\n
  • VLCD pin for contrast voltage adjustment<\/li>\n
  • Power-down command reduces standby current to 0.1\u00b5A<\/li>\n<\/ul>\n

    \u5e94\u7528<\/h2>\n
      \n
    • Multimeters and measuring instruments<\/li>\n
    • Home appliance LCD displays<\/li>\n
    • Battery-powered consumer electronics<\/li>\n
    • Industrial meters and gauges<\/li>\n
    • Water and gas meters<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The HT1621B is a 128-pattern (32×4) RAM-mapping LCD driver controller from Holtek Semiconductor with 3-wire serial interface, built-in RC\/XT oscillator, watchdog timer, and buzzer output in a 48-pin SSOP\/LQFP package. Key Specifications LCD Pattern 128 (32×4) Display RAM 32 x 4 bits Bias Options 1\/2 or 1\/3 bias Duty Options 1\/2, 1\/3, or […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13,20],"tags":[],"chip_brand":[262],"class_list":["post-7836","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-interface-ics","chip_brand-holtek"],"acf":{"brief_explanation":"128-pattern LCD driver, 32x4 RAM, 3-wire serial, WDT, buzzer, 2.4-5.2V, SSOP-48","date_code":"","package_case":"SSOP-48 (11.0 x 7.5mm) \/ LQFP-44","in_stock":4280,"datasheet":"https:\/\/www.holtek.com\/webapi\/116711\/HT1621_21Gv340.pdf","price":"$0.85 @ 1ku","product_introduction":"The HT1621B is a 128-pattern (32x4) RAM-mapping LCD driver from Holtek Semiconductor designed for segment-type LCD displays. It integrates a 32x4 bit display RAM, LCD bias generator, watchdog timer, and buzzer driver. The device communicates with the host MCU via a simple 3-wire serial interface (CS, WR, DATA, RD), requiring only 3-4 GPIO pins. Software-configurable bias (1\/2 or 1\/3) and duty (1\/2, 1\/3, or 1\/4) options ensure compatibility with most LCD panel types. The built-in 256kHz RC oscillator eliminates external clock components, while an optional 32.768kHz crystal provides higher accuracy. The power-down command reduces current to 0.1\u00b5A for battery-powered applications.","working_principle":"The HT1621B uses a RAM-mapping architecture where each bit in the 32x4 display RAM corresponds directly to an LCD segment. When the host MCU writes data to a RAM address via the 3-wire serial interface, the corresponding LCD segment is turned on or off. The LCD driving waveform is generated by the internal bias generator and COM\/SEG drivers, producing the AC voltage required for LCD operation (DC voltage would damage the liquid crystal). The driving clock is derived from the system clock (internal RC, external crystal, or external clock) and is fixed at 256Hz. The 1\/2 or 1\/3 bias configuration sets the intermediate voltage levels for the LCD waveform, while the duty setting (1\/2, 1\/3, 1\/4) determines the number of common lines scanned. The watchdog timer uses 8 selectable clock sources and asserts the IRQ pin on overflow. The buzzer output generates 2kHz or 4kHz tones by toggling the BZ and BZB pins in push-pull mode. The VLCD pin allows external adjustment of the LCD bias voltage for contrast control.","pin_description":"\n
      Pin Group<\/th>Count<\/th>Function<\/th>Description<\/th><\/tr>\n
      SEG0-SEG31<\/td>32<\/td>LCD Segment Output<\/td>LCD segment driver outputs<\/td><\/tr>\n
      COM0-COM3<\/td>4<\/td>LCD Common Output<\/td>LCD common driver outputs<\/td><\/tr>\n
      CS<\/td>1<\/td>Digital Input<\/td>Chip select (active low, initializes serial interface)<\/td><\/tr>\n
      WR<\/td>1<\/td>Digital Input<\/td>Write clock input<\/td><\/tr>\n
      RD<\/td>1<\/td>Digital Input<\/td>Read clock input<\/td><\/tr>\n
      DATA<\/td>1<\/td>Digital I\/O<\/td>Serial data input\/output<\/td><\/tr>\n
      IRQ<\/td>1<\/td>Digital Output<\/td>WDT\/time base overflow output<\/td><\/tr>\n
      BZ\/BZB<\/td>2<\/td>Digital Output<\/td>Buzzer outputs (push-pull pair)<\/td><\/tr>\n
      OSCI\/OSCO<\/td>2<\/td>Oscillator<\/td>Crystal oscillator input\/output<\/td><\/tr>\n
      VLCD<\/td>1<\/td>Analog<\/td>LCD bias voltage input for contrast control<\/td><\/tr>\n
      VDD\/VSS<\/td>2<\/td>Power<\/td>Supply (2.4-5.2V) and ground<\/td><\/tr>\n<\/table>","application_scenarios":"
        \n
      • Digital Multimeters:<\/strong> 32x4 LCD driver segments display voltage, current, and resistance readings with 3-wire MCU interface<\/li>\n
      • Water\/Gas Meters:<\/strong> 0.1\u00b5A standby current extends battery life; WDT provides system supervision<\/li>\n
      • Home Appliances:<\/strong> Built-in buzzer for audible alerts; VLCD pin adjusts contrast for different viewing angles<\/li>\n
      • Consumer Electronics:<\/strong> Software-configurable bias\/duty supports various LCD panels without hardware changes<\/li>\n
      • Battery Devices:<\/strong> Power-down mode reduces current to 0.1\u00b5A; RC oscillator eliminates external crystal<\/li>\n<\/ul>","alternative_models":"\n
        Model<\/th>Manufacturer<\/th>Key Difference<\/th>Package<\/th>Specs<\/th><\/tr>\n
        HT1621<\/td>Holtek<\/td>Original 44-pin LQFP version<\/td>-<\/td>-<\/td><\/tr>\n
        HT1623<\/td>Holtek<\/td>96x4 pattern, 48+16 SEG, larger display<\/td>-<\/td>-<\/td><\/tr>\n
        HT1625<\/td>Holtek<\/td>128x4 pattern, 64 SEG, more segments<\/td>-<\/td>-<\/td><\/tr>\n
        PCF8576D<\/td>NXP<\/td>I2C interface, 40x4 LCD driver<\/td>-<\/td>-<\/td><\/tr>\n
        BU9792AFUV<\/td>Rohm<\/td>I2C, 80-segment, 1\/4 duty, VQFP-48<\/td>-<\/td>-<\/td><\/tr>\n<\/table>"},"_links":{"self":[{"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/posts\/7836","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/comments?post=7836"}],"version-history":[{"count":0,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/posts\/7836\/revisions"}],"wp:attachment":[{"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/media?parent=7836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/categories?post=7836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/tags?post=7836"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/ic-vendor.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=7836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}