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HT16C21A-28SSOP
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Holtek Semicon LCD Drivers, SSOP-28-150mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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Symbol & Footprint
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Datasheet
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README
markdownHT16C21A-28SSOP
Holtek Semicon · LCD Drivers · SSOP-28-150mil
HT16C21A-28SSOP from Holtek Semicon, in a SSOP-28-150mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VDD | power_in | Positive power supply, operating range 2.4V to 5.5V. |
| 2 | SDA | bidirectional | I2C interface serial data input/output. |
| 3 | SCL | input | I2C interface serial clock input. |
| 4 | VSS | power_in | Negative power supply, ground. |
| 5 | COM0 | output | LCD COM output. |
| 6 | COM1 | output | LCD COM output. |
| 7 | COM2 | output | LCD COM output. |
| 8 | COM3 | output | LCD COM output. |
| 9 | COM4/SEG0 | output | LCD COM/SEG multiplexed drive output. |
| 10 | COM5/SEG1 | output | LCD COM/SEG multiplexed drive output. |
| 11 | COM6/SEG2 | output | LCD COM/SEG multiplexed drive output. |
| 12 | COM7/SEG3 | output | LCD COM/SEG multiplexed drive output. |
| 13 | SEG4 | output | LCD SEG output. |
| 14 | SEG5 | output | LCD SEG output. |
| 15 | SEG6 | output | LCD SEG output. |
| 16 | SEG7 | output | LCD SEG output. |
| 17 | SEG8 | output | LCD SEG output. |
| 18 | SEG9 | output | LCD SEG output. |
| 19 | SEG10 | output | LCD SEG output. |
| 20 | SEG11 | output | LCD SEG output. |
| 21 | SEG12 | output | LCD SEG output. |
| 22 | SEG13 | output | LCD SEG output. |
| 23 | SEG14 | output | LCD SEG output. |
| 24 | SEG15 | output | LCD SEG output. |
| 25 | SEG16 | output | LCD SEG output. |
| 26 | SEG17 | output | LCD SEG output. |
| 27 | SEG18 | output | LCD SEG output. |
| 28 | SEG19/VLCD | bidirectional | Shared SEG19 output or VLCD pin (set by the DE bit): as VLCD, an external resistor to VDD sets the bias voltage when internal adjustment is disabled, or it outputs the adjusted voltage for MCU sensing when enabled. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Holtek Semicon |
| Package | SSOP-28-150mil |
| Category | LED Drivers |
| Pins | 28 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Operating voltage | VDD | 2.4 | 5.5 | V | 7 | ||
| Operating current (display on, 1/3 bias, 80Hz) | IDD | 18 | 36 | μA | 3V 无负载，VLCD=VDD，1/3 bias，fLCD=80Hz，LCD显示开启，内部系统振荡器开启，DA0~DA3=0000 | 7 | |
| Operating current (display on, 1/3 bias, 80Hz) | IDD | 25 | 50 | μA | 5V | 7 | |
| Operating current (display off) | IDD1 | 2 | 5 | μA | 3V 无负载，VLCD=VDD，1/3 bias，fLCD=80Hz，LCD显示关闭，内部系统振荡器开启，DA0~DA3=0000 | 7 | |
| Operating current (display off) | IDD1 | 4 | 10 | μA | 5V | 7 | |
| Standby current | ISTB | 1 | μA | 3V 无负载，VLCD=VDD，LCD显示关闭，内部系统振荡器关闭 | 7 | ||
| Standby current | ISTB | 2 | μA | 5V | 7 | ||
| Low-level input voltage | VIL | 0 | V | SDA，SCL | 7 | ||
| Input leakage current | IIL | -1 | 1 | μA | VIN=VSS 或 VDD | 8 | |
| Low-level output current (SDA) | IOL | 3 | mA | 3V, VOL=0.4V, SDA pin | 8 | ||
| Low-level output current (SDA) | IOL | 6 | mA | 5V | 8 | ||
| LCD COM sink current | IOL1 | 250 | 400 | μA | 3V, VLCD=3V, VOL=0.3V | 8 | |
| LCD COM sink current | IOL1 | 500 | 800 | μA | 5V, VLCD=5V, VOL=0.5V | 8 | |
| LCD COM source current | IOH1 | -140 | -230 | μA | 3V, VLCD=3V, VOH=2.7V | 8 | |
| LCD COM source current | IOH1 | -300 | -500 | μA | 5V, VLCD=5V, VOH=4.5V | 8 | |
| LCD SEG sink current | IOL2 | 250 | 400 | μA | 3V, VLCD=3V, VOL=0.3V | 8 | |
| LCD SEG sink current | IOL2 | 500 | 800 | μA | 5V, VLCD=5V, VOL=0.5V | 8 | |
| LCD SEG source current | IOH2 | -140 | -230 | μA | 3V, VLCD=3V, VOH=2.7V | 8 | |
| LCD SEG source current | IOH2 | -300 | -500 | μA | 5V, VLCD=5V, VOH=4.5V | 8 | |
| LCD frame frequency | fLCD1 | 72 | 80 | 88 | Hz | 4V, 1/4 duty, Ta=25°C | 8 |
| LCD frame frequency (160Hz setting) | fLCD2 | 144 | 160 | 176 | Hz | 4V, 1/4 duty, Ta=25°C | 8 |
| LCD frame frequency | fLCD3 | 52 | 80 | 124 | Hz | 4V, 1/4 duty, Ta=-40°C~85°C | 8 |
| LCD frame frequency (160Hz setting) | fLCD4 | 104 | 160 | 248 | Hz | 4V, 1/4 duty, Ta=-40°C~85°C | 8 |
| Power-on reset voltage | VPOR | 100 | mV | 8 | |||
| Power-on reset VDD rise rate | RRVDD | 0.05 | V/ms | 8 | |||
| Minimum time VDD held at VPOR | tPOR | 10 | ms | 8 | |||
| SCL clock frequency | fSCL | 100 | kHz | VDD=2.4V~5.5V | 8 | ||
| SCL clock frequency | fSCL | 400 | kHz | VDD=3.0V~5.5V | 8 | ||
| Bus free time | tBUF | 4.7 | μs | VDD=2.4V~5.5V; 在此期间总线必须保持空闲直到新的传输开始 | 8 | ||
| Bus free time | tBUF | 1.3 | μs | VDD=3.0V~5.5V; 在此期间总线必须保持空闲直到新的传输开始 | 8 | ||
| START hold time | tHD:STA | 4 | μs | VDD=2.4V~5.5V; 此周期后，产生第一个时钟脉冲 | 8 | ||
| START hold time | tHD:STA | 0.6 | μs | VDD=3.0V~5.5V; 此周期后，产生第一个时钟脉冲 | 8 | ||
| SCL low time | tLOW | 4.7 | μs | VDD=2.4V~5.5V | 8 | ||
| SCL low time | tLOW | 1.3 | μs | VDD=3.0V~5.5V | 8 | ||
| SCL high time | tHIGH | 4 | μs | VDD=2.4V~5.5V | 8 | ||
| SCL high time | tHIGH | 0.6 | μs | VDD=3.0V~5.5V | 8 | ||
| START setup time | tSU:STA | 4.7 | μs | VDD=2.4V~5.5V; 仅与重复发送的 START 信号有关 | 8 | ||
| START setup time | tSU:STA | 0.6 | μs | VDD=3.0V~5.5V; 仅与重复发送的 START 信号有关 | 8 | ||
| Data hold time | tHD:DAT | 0 | ns | VDD=2.4V~5.5V | 8 | ||
| Data setup time | tSU:DAT | 250 | ns | VDD=2.4V~5.5V | 8 | ||
| Data setup time | tSU:DAT | 100 | ns | VDD=3.0V~5.5V | 8 | ||
| SDA and SCL rise time | tR | 1 | μs | VDD=2.4V~5.5V; 注：周期性采样测试，非100%测试 | 8 | ||
| SDA and SCL rise time | tR | 0.3 | μs | VDD=3.0V~5.5V; 注：周期性采样测试，非100%测试 | 8 | ||
| SDA and SCL fall time | tF | 0.3 | μs | VDD=2.4V~5.5V; 注：周期性采样测试，非100%测试 | 8 | ||
| STOP setup time | tSU:STO | 4 | μs | VDD=2.4V~5.5V | 8 | ||
| STOP setup time | tSU:STO | 0.6 | μs | VDD=3.0V~5.5V | 8 | ||
| Valid clock output time | tAA | 3.5 | μs | VDD=2.4V~5.5V | 8 | ||
| Valid clock output time | tAA | 0.9 | μs | VDD=3.0V~5.5V | 8 | ||
| Input filter time constant (SDA and SCL pins, noise suppression time) | tSP | 100 | ns | VDD=2.4V~5.5V; 注：周期性采样测试，非100%测试 | 9 | ||
| Input filter time constant (SDA and SCL pins, noise suppression time) | tSP | 50 | ns | VDD=3.0V~5.5V; 注：周期性采样测试，非100%测试 | 9 | ||
| Storage temperature | -60 | 150 | °C | 7 | |||
| Operating temperature | -40 | 85 | °C | 7 |
CAD (KiCad official)
- Symbol:
HT16C21A-28SSOP - Footprint:
Package_SO:SSOP-28_5.3x10.2mm_P0.65mm - 3D model: SSOP-28-150mil (KiCad packages3D, STEP)
- 3D model files:
ht16c21a-28ssop-etched.step/ht16c21a-28ssop-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);ht16c21a-28ssop.step/ht16c21a-28ssop.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Holtek Semicon datasheet (35 pp, sha256
9e2057530a66f187, retrieved 2026-10-18, tier: lcsc) - Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).