Specification	BQ4845S-A4TR

Current - Timekeeping (Max)	1.5 mA
Features	Alarm, Watchdog Timer, Supervisor, Leap Year, Daylight Savings
Interface	Parallel
Mounting Type	Surface Mount
Operating Temperature [Max]	70 °C
Operating Temperature [Min]	0 °C
Package / Case	28-SOIC
Package / Case [x]	0.295 in
Package / Case [y]	7.5 mm
Supplier Device Package	28-SOIC
Time Format	HH:MM:SS (12/24 hr)
Type	Clock/Calendar
Voltage - Supply [Max]	5.5 V
Voltage - Supply [Min]	4.75 V
Voltage - Supply, Battery [Max]	4 V
Voltage - Supply, Battery [Min]	2.3 V

BQ4845 Series

Part	Voltage - Supply [Min]	Voltage - Supply [Max]	Interface	Operating Temperature [Max]	Operating Temperature [Min]	Voltage - Supply, Battery [Min]	Voltage - Supply, Battery [Max]	Time Format	Current - Timekeeping (Max)	Package / Case	Package / Case [x]	Package / Case [y]	Features	Type	Supplier Device Package	Mounting Type	Package / Case	Package / Case
Texas Instruments BQ4845YS-A4NTR	4.5 V	5.5 V	Parallel	85 °C	-40 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845S-A4TR	4.75 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845S-A4NTRG4	4.75 V	5.5 V	Parallel	85 °C	-40 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845S-A4G4	4.75 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845P-A4	4.75 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-DIP			Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-PDIP	Through Hole	0.6 in	15.24 mm
Texas Instruments BQ4845S-A4	4.75 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845S-A4N	4.75 V	5.5 V	Parallel	85 °C	-40 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845YS-A4	4.5 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845YS-A4TR	4.5 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-SOIC	0.295 in	7.5 mm	Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-SOIC	Surface Mount
Texas Instruments BQ4845YP-A4	4.5 V	5.5 V	Parallel	70 °C	0 °C	2.3 V	4 V	HH:MM:SS (12/24 hr)	1.5 mA	28-DIP			Alarm Daylight Savings Leap Year Supervisor Watchdog Timer	Clock/Calendar	28-PDIP	Through Hole	0.6 in	15.24 mm

Pricing

Prices provided here are for design reference only. For realtime values and availability, please visit the distributors directly

Distributor	Package	Quantity	$

Digikey	Tape & Reel (TR)	1000	$ 7.76
Texas Instruments	LARGE T&R	1	$ 10.63
		100	$ 8.66
		250	$ 6.81
		1000	$ 5.78

Description

General part information

BQ4845 Series

The bq4845 Real-Time Clock is a low-power microprocessor peripheral that integrates a time-of-day clock, a 100-year calendar, and a CPU supervisor in a 28-pin SOIC or DIP. The bq4845 is ideal for fax machines, copiers, industrial control systems, point-of-sale terminals, data loggers, and computers.

The bq4845 provides direct connections for a 32.768KHz quartz crystal and a 3V backup battery. Through the use of the conditional chip enable output (CE\OUT) and battery voltage output (VOUT) pins, the bq4845 can write-protect and make nonvolatile external SRAMs. The backup cell powers the real-time clock and maintains SRAM information in the absence of system voltage.

The bq4845 contains a temperature-compensated reference and comparator circuit that monitors the status of its voltage supply. When the bq4845 detects an out-of-tolerance condition, it generates an interrupt warning and subsequently a microprocessor reset. The reset stays active for 200ms after VCCrises within tolerance, to allow for power supply and processor stabilization.

Documents

Technical documentation and resources

BQ4845S-A4TR

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BQ4845S-A4TR

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Technical Specifications

BQ4845 Series

Pricing

Description

BQ4845 Series

Documents

Parallel RTC With CPU Supervisor datasheet

U-502 Time-Base Oscillator for RTC IC

U-500 Using the bq4845 for a Low-Cost RTC/NVSRAM Subsystem

BQ4845 Series