IC-Mart Your Trusted Source for Real Time Clock Chips

(from leading manufacturers)

Top Global RTC Manufacturers and Typical Models

1. Analog Devices (Maxim Integrated)

• High Precision / Integrated Crystal (TCXO): DS3231 (The industry benchmark), DS3232, MAX31343 (MEMS Oscillator), MAX31328.
• General Purpose (I2C/SPI): DS1307 (Most common), DS1338, DS1302 (3-wire interface), DS1339.
• Parallel Interface (Timekeeper): DS12885, DS1742 (With storage), DS1744.
• Ultra-Low Power: MAX31331, MAX31334.

2. NXP Semiconductors

• Industrial / General Purpose: PCF8563 (Highly cost-effective), PCF85063, PCF8523.
• High Precision / Modular: PCF2127 (Integrated crystal), PCF2129, PCA2129 (Automotive grade).
• Miniaturized Packaging: PCF85263A (Feature-rich, tiny footprint).

3. STMicroelectronics

• Serial Interface: M41T62, M41T82, M41T94.
• Parallel / Memory Type: M48T35 (Classic Timekeeper), M48T58, M48T02.
• Special Functions: M41ST87W (With physical anti-tamper detection).

4. Microchip Technology

• Integrated Storage: MCP79410 (With 128B EEPROM), MCP7940N.
• High Performance / Serial: MCP79510 (SPI interface), MCP79520.
• Low Power: MCP7940M.

5. Micro Crystal & Epson

• Micro Crystal: RV-3028-C7 (Among the lowest power on the market, 45nA), RV-8803-C7 (High precision), RV-3032-C7.
• Epson: RX-8803SA (High precision TCXO), RX-8900SA, RX-4571.

6. Other Specialized Manufacturers

• Ambiq Micro: AM1805, AM1815.
• Renesas (Intersil): Stable in consumer and industrial markets. Models: ISL1208, ISL12022 (High precision temp-compensated).
• Texas Instruments (TI): BQ32000, BQ32002.

Manufacturer Strengths and Use Cases

Manufacturer	Core Competitive Advantage	Recommended Application Scenarios
Analog Devices	Extremely high precision (DS3231) and the most diverse portfolio.	Communication equipment, high-end industrial instruments, servers.
NXP	Stable supply chain and abundant automotive-grade models.	Smart meters, home appliances, automotive electronics.
Micro Crystal	Extreme low power (nA level) and tiny packaging.	Medical implants, smart wearables, IoT sensors.
ST / Microchip	High memory integration; combines timekeeping with logic control.	Industrial control boards, security systems, parameter backup.

Top Chinese RTC Manufacturers and Typical Models

1. Industry Leaders & High Precision (Precision & Industrial)

These chips usually integrate temperature-compensated crystal oscillators (TCXO). They are primarily used as alternatives to Maxim’s DS3231/DS3232 in power meters and telecom equipment.

Manufacturer	Typical Model	Core Advantage	Cross-Reference / International Alternative
Sunvofine (兴威帆)	SD2405AL	Highest domestic reputation. Integrated crystal, battery, and charging circuit. Extremely precise.	DS3231 (Fully compatible)
	SD2400 / SD2403	Industrial-grade stability. Widely used in smart meters.	DS1302 / PCF8563 upgrade
Aura (奥拉股份)	Au1901	Server-grade / High reliability. Part of Intel reference designs; supports dual channels.	Dedicated server RTC
Novosense (纳芯微)	NSR1302	Focused on industrial and automotive sectors. High reliability.	DS1302 / Automotive RTC

2. General Purpose & Value Models (General Purpose & Consumer)

These are mostly Pin-to-Pin (P2P) compatible with classic models from Maxim or NXP. They are volume drivers in B2B export markets.

Manufacturer	Typical Model	Features	Cross-Reference / International Alternative
Belling (上海贝岭)	BL8563	Extremely stable performance. A top choice for domestic replacement.	PCF8563
	BL5372	Optimized for consumer electronics.	Ricoh RS5C372
I-Core (中微爱芯)	AiP8563	Significant price advantage. Ideal for large-scale consumer apps.	PCF8563
	AiP1302	Classic trickle-charge clock chip.	DS1302
	AiP1307	Supports 56B of non-volatile RAM.	DS1307
Ruimeng (杭州瑞盟)	MS8563	Excellent low-power design. Widely used in IoT.	PCF8563
	MS1302	Good compatibility and short lead times.	DS1302
Haoyu (无锡浩宇)	HYM8563	Massive shipment volume in the South China electronics market.	PCF8563

3. Ultra-Low Power & Specialized Models

Manufacturer	Typical Model	Features	Cross-Reference / International Alternative
SGMicro (圣邦微)	SGM1302	Extremely low static current. Ideal for handheld devices.	DS1302 (Low power version)
WCH (沁恒微)	CH455 / CH452	Typically integrates RTC into interface chips. Good for LED driving.	General RTC functions

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Real Time Clock Core Technical Features

• Ultra-Low Power: Operating current is typically at the nanoAmp (nA) level. A single coin cell can power the chip for several years.
• Calendar Functions: Automatically handles leap years and variable month lengths.
• Frequency Reference: Uses an external or internal 32.768 kHz quartz crystal oscillator.
• Power Management: Seamlessly switches to backup power if the main voltage drops.

Typical Application Scenarios

1. Smart Meters & Energy Management

This is one of the largest markets for RTCs.

• Tiered Pricing: Meters need precise time to apply different rates (peak vs. off-peak).
• Event Logging: Records the exact time of power outages, trips, or illegal tampering.

2. Industrial Control & Data Acquisition (PLC/Loggers)

• Maintenance Alerts: Tracks cumulative runtime to schedule regular servicing.
• Fault Tracing: Provides accurate timestamps for system errors to help engineers analyze failure sequences.

3. Consumer Electronics & PC Peripherals

• Mainboards / Laptops: Keeps the system time accurate even when the device is unplugged or the main battery is dead.
• Wearables: Allows smartwatches to keep time when not synced with a phone.

4. Telecom & Networking (Gateways/Routers)

• Log Management: Ensures system logs have accurate time tags.
• Offline Sync: Serves as the time reference when NTP sync is unavailable.

5. Security Surveillance (CCTV/DVR)

• Evidence Integrity: Video timestamps must be highly accurate for legal admissibility.

6. Automotive Electronics

• T-Box / Dashcams: Records event times after the engine is off or provides time data during emergency calls (eCall).

The Four Main Classifications

1. By Bus Interface

Determines how the chip connects to the host controller (MCU/CPU).

Classification	Features	Typical Models	Manufacturer
I2C Interface	Low pin count (2 wires). Most common; supports multiple devices on one bus.	DS1307 / DS1338, PCF8563 / PCF2123	Analog Devices, NXP
SPI Interface	Faster data transfer (3/4 wires). Good for high-frequency exchanges.	DS1306, MCP79511	Analog Devices, Microchip
Parallel Interface	Similar to SRAM access. Fast read/write; often includes large storage.	DS12885, M48T35	Analog Devices, ST

2. By Accuracy & TCXO

Accuracy depends heavily on environmental temperature.

Classification	Features	Typical Models	Manufacturer
Standard Accuracy	Requires external 32.768 kHz crystal; prone to temperature drift.	DS1302, M41T82	Analog Devices, ST
High Precision (TCXO)	Integrated temperature compensation ensures accuracy during temperature spikes.	DS3231, RX-8803SA, RV-3028-C7	Analog Devices, Epson, Micro Crystal

3. By Integration & Packaging

Refers to the complexity of the internal circuit design.

Classification	Features	Typical Models	Manufacturer
External Crystal	Lowest cost. Requires external crystal and capacitor matching.	MCP7940N, ISL1208	Microchip, Renesas
Internal Crystal	Crystal is inside the package. Saves PCB space and resists interference.	DS3232M, PCF2127	Analog Devices, NXP
Fully Integrated	Includes an internal battery or supercapacitor for total independence.	DS1904 (iButton), M41T94	Analog Devices, ST

4. By Power & Special Features

Designed for specific niches like wearables or industrial control.

Classification	Features	Typical Models	Manufacturer
Ultra-Low Power	nA-level current. Ideal for long-term battery operation.	AM1805, RV-1805-C3	Ambiq Micro, Micro Crystal
Non-Volatile Memory	Preserves system parameters during power loss (NVRAM/EEPROM).	DS1338 (56B RAM), MCP79410 (128B EE)	Analog Devices, Microchip
Power Management	Supports trickle charging for backup batteries or supercapacitors.	DS1340, RV-3028	Analog Devices, Micro Crystal