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BQ4285 具有 114x8 NVSRAM 和 NVSRAM 控制的 RTC IC

BQ4285 描述

The CMOS bq4285 is a low-power microprocessor peripheral providing a time-of-day clock and 100-year calendar with alarm features and battery operation. Other features include three maskable interrupt sources, square wave output, and 114 bytes of general nonvolatile storage. The bq4285 write-protects the clock, calendar, and storage registers during power failure. A backup battery then maintains data and operates the clock and calendar. The bq4285 is a fully compatible real-time clock for IBM AT-compatible computers and other applications. The only external components are a 32.768kHz crystal and a backup battery. The bq4285 integrates a battery-backup controller to make a standard CMOS SRAM nonvolatile during power-fail conditions

	BQ4285
Supply Voltage(V)	5
Bus Interface	Multiplexed
Memory Density(Kb)	0.114
Operating Temperature Range(°C)	0 to 70
Pin/Package	24PDIP, 24SOIC
Approx. Price (US$)	2.90 | 1ku
RTC Bytes	14

BQ4285 特性

• Direct clock/calendar replacement for IBM® AT-compatible computers and other applications
• Functionally compatible with the DS1285
  • Closely matches MC146818A pin configuration
• 114 bytes of general nonvolatile storage
• Automatic backup and write-protect control to external SRAM
• 160 ns cycle time allows fast bus operation
• Less than 0.5µA load under battery operation
• 14 bytes for clock/calendar and control
• Calendar in day of the week, day of the month, months, and years, with automatic leap-year adjustment
• Time of day in seconds, minutes, and hours
  • 12- or 24-hour format
  • Optional daylight saving adjustment
• BCD or binary format for clock and calendar data
• Programmable square wave out-put
• Three individually maskable interrupt event flags:
  • Periodic rates from 122 us to 500 ms
  • Time-of-day alarm once per second to once per day
  • End-of-clock update cycle
• 24-pin plastic DIP or SOIC

BQ4285 芯片订购指南

器件	状态	温度 (oC)	价格（美元）	封装 | 引脚	封装数量 | 封装载体	丝印标记
BQ4285P-SB2	ACTIVE	0 to 70	2.90 | 1ku	PDIP (N) | 24	15 | TUBE	4285P -SB2
BQ4285S-SB2	ACTIVE	0 to 70	3.50 | 1ku	SOIC (DW) | 24	25 | TUBE	4285S -SB2
BQ4285S-SB2G4	ACTIVE	0 to 70	3.50 | 1ku	SOIC (DW) | 24	25 | TUBE	4285S -SB2
BQ4285S-SB2TR	ACTIVE	0 to 70	2.90 | 1ku	SOIC (DW) | 24	2000 | LARGE T&R	4285S -SB2
BQ4285S-SB2TRG4	ACTIVE	0 to 70	2.90 | 1ku	SOIC (DW) | 24	2000 | LARGE T&R	4285S -SB2

BQ4285 质量与无铅数据

器件	环保计划*	铅/焊球涂层	MSL 等级/回流焊峰	环保信息与无铅 (Pb-free)	DPPM / MTBF / FIT 率
BQ4285P-SB2	Pb-Free (RoHS)	A42 SN	N/A for Pkg Type	BQ4285P-SB2	BQ4285P-SB2
BQ4285S-SB2	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	BQ4285S-SB2	BQ4285S-SB2
BQ4285S-SB2G4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	BQ4285S-SB2G4	BQ4285S-SB2G4
BQ4285S-SB2TR	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	BQ4285S-SB2TR	BQ4285S-SB2TR
BQ4285S-SB2TRG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	BQ4285S-SB2TRG4	BQ4285S-SB2TRG4

BQ4285 应用技术支持与电子电路设计开发资源下载

1. BQ4285 数据资料 dataSheet 下载.PDF
2. TI 德州仪器实时时钟产品选型与价格 . xls
3. PowerPAD™ Thermally Enhanced Package   (PDF  1040 KB)
4. 全面认识开关型电源中的BUCK-BOOST功率级 (Rev. A)   (PDF  2206 KB)
5. Shelf-Life Evaluation of Lead-Free Component Finishes (PDF 1305 KB)
6. PowerPAD™ Made Easy (PDF 57 KB)
7. 标准线性产品交叉参考 (Rev. D)   (PDF  1058 KB)
8. 模数规格和性能特性术语表 (Rev. A) (PDF 1993 KB)
9. 所选封装材料的热学和电学性质 (PDF 645 KB)
10. 高速数据转换 (PDF 1967 KB)

BQ4285 相关工具

名称	型号	公司	工具/软件类型
BQ4285 评估模块	BQ4285EVM	Texas Instruments	开发电路板/EVM