DS14285N datasheet, PDF - EEWORLD Datasheet

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DS14285N: Description1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, DIP-24; CategoryThe embedded processor and controller Microcontrollers and processors; File Size1MB，27 Pages; ManufacturerRochester Electronics; Websitehttps://www.rocelec.com/

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DS14285N Overview

1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, DIP-24

DS14285N Parametric

Parameter Name	Attribute value
Is it lead-free?	Contains lead
Is it Rohs certified?	incompatible
Maker	Rochester Electronics
Parts packaging code	DIP
package instruction	DIP,
Contacts	24
Reach Compliance Code	unknown
maximum clock frequency	0.032 MHz
External data bus width	8
Information access methods	PARALLEL, MUXED BUS
JESD-30 code	R-PDIP-T24
JESD-609 code	e0
length	31.75 mm
Humidity sensitivity level	1
Number of terminals	24
Number of timers	1
Maximum operating temperature	85 °C
Minimum operating temperature	-40 °C
Package body material	PLASTIC/EPOXY
encapsulated code	DIP
Package shape	RECTANGULAR
Package form	IN-LINE
Peak Reflow Temperature (Celsius)	240
Certification status	COMMERCIAL
Maximum seat height	5.08 mm
Maximum supply voltage	5.5 V
Minimum supply voltage	4.5 V
Nominal supply voltage	5 V
surface mount	NO
Temperature level	INDUSTRIAL
Terminal surface	TIN LEAD
Terminal form	THROUGH-HOLE
Terminal pitch	2.54 mm
Terminal location	DUAL
Maximum time at peak reflow temperature	20
width	15.24 mm
uPs/uCs/peripheral integrated circuit type	TIMER, REAL TIME CLOCK
Base Number Matches	1

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DS14285/DS14287

DETAILED DESCRIPTION

The DS14285/DS14287 Real Time Clock with NVRAM Control provides the industry standard DS1287

clock function with the additional feature of providing nonvolatile control for an external SRAM.

Functions include a nonvolatile time-of-day clock, alarm, 100-year calendar, programmable interrupt,

square wave generator, and 114 bytes of nonvolatile static RAM. For the DS14287 a lithium energy

source, quartz crystal, and write protection circuitry are contained within a 24-pin dual in-line package.

The DS14285 requires an external quartz crystal connected to the X1 and X2 pins as well as an external

energy source connected to the V

BAT

pin. A standard 32.768 kHz quartz crystal can be directly connected

to the DS14285 via pins 1 and 2 (X1, X2). The crystal selected for use should have a specified load

capacitance (C

) of 6 pF. For more information on crystal selection and crystal layout considerations,

please consult Application Note 58, “Crystal Considerations with Dallas Real-time Clocks.”

The DS14285/DS14287 uses its backup energy source and battery-backup controller to make a standard

CMOS static RAM nonvolatile during power-fail conditions. During power fail, the DS14285/DS14287

automatically write-protects the external SRAM and provides a V

output sourced from its internal

battery.

For the DS14287 the internal lithium cell is electrically isolated from the clock and memory when

shipped from the factory. This isolation is removed after the first application of V

CC,

allowing the lithium

cell to provide data retention to the clock, internal RAM, V

CCO

and

CEO

on subsequent power-downs.

Care must be taken after this isolation has been broken to avoid inadvertently discharging the lithium cell

through the V

CCO

and

CEO

pins.

OPERATION

The block diagram in Figure 1 shows the pin connections with the major internal functions of the

DS14285/DS14287. The following paragraphs describe the function of each pin.

SIGNAL DESCRIPTIONS

GND, V

- DC power is provided to the device on these pins. V

is the +5 volt input.

SQW (Square Wave Output)

- The SQW pin can output a signal from one of 13 taps provided by the 15

internal divider stages of the real time clock. The frequency of the SQW pin can be changed by

programming Register A as shown in Table 1. The SQW signal can be turned on and off using the SQWE

bit in Register B. The SQW signal is not available when V

is less than 4.25 volts typical.

AD0-AD7 (Multiplexed Bi-directional Address/Data Bus)

- Multiplexed buses save pins because

address information and data information time-share the same signal paths. The addresses are present

during the first portion of the bus cycle and the same pins and signal paths are used for data in the second

portion of the cycle. Address/data multiplexing does not slow the access time of the DS14285/DS14287

since the bus change from address to data occurs during the internal RAM access time. Addresses must be

valid prior to the falling edge of AS/ALE, at which time the DS14285/DS14287 latches the address from

AD0 to AD6. Valid write data must be present and held stable during the latter portion of the DS or

pulses. In a read cycle the DS14285/DS14287 outputs 8 bits of data during the latter portion of the DS or

pulses. The read cycle is terminated and the bus returns to a high impedance state as DS transitions

low in the case of Motorola timing or as

transitions high in the case of Intel timing.

3 of 26

DS14285N Related Products

	DS14285N	DS14285Q+	DS14285	DS14285S+	DS14285+	DS14285Q	DS14285N+	DS14285QN+	DS14287
Description	1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, DIP-24	1 TIMER(S), REAL TIME CLOCK, PQCC28, ROHS COMPLIANT, PLASTIC, LCC-28	1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, DIP-24	1 TIMER(S), REAL TIME CLOCK, PDSO24, 0.300 INCH, ROHS COMPLIANT, SOP-24	1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, ROHS COMPLIANT, DIP-24	1 TIMER(S), REAL TIME CLOCK, PQCC28, PLASTIC, LCC-28	1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.600 INCH, ROHS COMPLIANT, DIP-24	1 TIMER(S), REAL TIME CLOCK, PQCC28, ROHS COMPLIANT, PLASTIC, LCC-28	1 TIMER(S), REAL TIME CLOCK, PDIP24, 0.740 INCH, ENCAPSULATED, DIP-24
Is it lead-free?	Contains lead	Lead free	Contains lead	Lead free	Lead free	Contains lead	Lead free	Lead free	Contains lead
Is it Rohs certified?	incompatible	conform to	incompatible	conform to	conform to	incompatible	conform to	conform to	incompatible
Maker	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics	Rochester Electronics
Parts packaging code	DIP	QLCC	DIP	SOIC	DIP	QLCC	DIP	QLCC	DIP
package instruction	DIP,	QCCJ,	DIP,	0.300 INCH, ROHS COMPLIANT, SOP-24	DIP,	QCCJ,	DIP,	ROHS COMPLIANT, PLASTIC, LCC-28	0.740 INCH, ENCAPSULATED, DIP-24
Contacts	24	28	24	24	24	28	24	28	24
Reach Compliance Code	unknown	unknown	unknown	unknown	unknown	unknown	unknown	unknown	unknown
maximum clock frequency	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz	0.032 MHz
External data bus width	8	8	8	8	8	8	8	8	8
Information access methods	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS	PARALLEL, MUXED BUS
JESD-30 code	R-PDIP-T24	S-PQCC-J28	R-PDIP-T24	R-PDSO-G24	R-PDIP-T24	S-PQCC-J28	R-PDIP-T24	S-PQCC-J28	R-PDIP-T24
JESD-609 code	e0	e3	e0	e3	e3	e0	e3	e3	e0
length	31.75 mm	11.505 mm	31.75 mm	15.415 mm	31.75 mm	11.505 mm	31.75 mm	11.505 mm	31.75 mm
Number of terminals	24	28	24	24	24	28	24	28	24
Number of timers	1	1	1	1	1	1	1	1	1
Maximum operating temperature	85 °C	70 °C	70 °C	70 °C	70 °C	70 °C	85 °C	85 °C	70 °C
Package body material	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY	PLASTIC/EPOXY
encapsulated code	DIP	QCCJ	DIP	SOP	DIP	QCCJ	DIP	QCCJ	DIP
Package shape	RECTANGULAR	SQUARE	RECTANGULAR	RECTANGULAR	RECTANGULAR	SQUARE	RECTANGULAR	SQUARE	RECTANGULAR
Package form	IN-LINE	CHIP CARRIER	IN-LINE	SMALL OUTLINE	IN-LINE	CHIP CARRIER	IN-LINE	CHIP CARRIER	IN-LINE
Peak Reflow Temperature (Celsius)	240	260	240	260	260	245	260	260	240
Certification status	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL
Maximum seat height	5.08 mm	4.57 mm	5.08 mm	2.68 mm	5.08 mm	4.57 mm	5.08 mm	4.57 mm	5.08 mm
Maximum supply voltage	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V
Minimum supply voltage	4.5 V	4.5 V	4.5 V	4.5 V	4.5 V	4.5 V	4.5 V	4.5 V	4.5 V
Nominal supply voltage	5 V	5 V	5 V	5 V	5 V	5 V	5 V	5 V	5 V
surface mount	NO	YES	NO	YES	NO	YES	NO	YES	NO
Temperature level	INDUSTRIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	COMMERCIAL	INDUSTRIAL	INDUSTRIAL	COMMERCIAL
Terminal surface	TIN LEAD	TIN	TIN LEAD	TIN	MATTE TIN	TIN LEAD	MATTE TIN	TIN	TIN LEAD
Terminal form	THROUGH-HOLE	J BEND	THROUGH-HOLE	GULL WING	THROUGH-HOLE	J BEND	THROUGH-HOLE	J BEND	THROUGH-HOLE
Terminal pitch	2.54 mm	1.27 mm	2.54 mm	1.27 mm	2.54 mm	1.27 mm	2.54 mm	1.27 mm	2.54 mm
Terminal location	DUAL	QUAD	DUAL	DUAL	DUAL	QUAD	DUAL	QUAD	DUAL
Maximum time at peak reflow temperature	20	NOT SPECIFIED	20	NOT SPECIFIED	30	NOT SPECIFIED	30	NOT SPECIFIED	NOT SPECIFIED
width	15.24 mm	11.505 mm	15.24 mm	7.51 mm	15.24 mm	11.505 mm	15.24 mm	11.505 mm	15.24 mm
uPs/uCs/peripheral integrated circuit type	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK	TIMER, REAL TIME CLOCK
Humidity sensitivity level	1	NOT APPLICABLE	1	1	1	NOT APPLICABLE	1	NOT APPLICABLE	-
Base Number Matches	1	1	1	1	1	1	1	1	-
technology	-	CMOS	CMOS	CMOS	CMOS	CMOS	-	-	CMOS

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