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參數(shù)資料
| 型號： | DS12CR887-5+ |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 4/23頁 |
| 文件大小： | 0K |
| 描述： | IC RTC W/RAM 128 BYTE 24-EDIP |
| 產(chǎn)品培訓(xùn)模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標(biāo)準(zhǔn)包裝： | 14 |
| 類型： | 時鐘/日歷 |
| 特點(diǎn)： | 警報器，閏年，NVSRAM，方波輸出，涓流充電器 |
| 存儲容量： | 114B |
| 時間格式： | HH:MM:SS（12/24 小時） |
| 數(shù)據(jù)格式： | YY-MM-DD-dd |
| 接口： | 并聯(lián) |
| 電源電壓： | 4.5 V ~ 5.5 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 通孔 |
| 封裝/外殼： | 24-DIP 模塊（0.600"，15.24mm） |
| 供應(yīng)商設(shè)備封裝： | 24-EDIP |
| 包裝： | 管件 |
| 產(chǎn)品目錄頁面： | 1433 (CN2011-ZH PDF) |
DS12R885/DS12CR887/DS12R887
RTCs with Constant-Voltage Trickle Charger
12
Maxim Integrated
Detailed Description
The DS12R885 is a drop-in replacement for the
DS12885 RTC. The device provides 14 bytes of real-
time clock/calendar, alarm, and control/status registers
and 114 bytes of nonvolatile, battery-backed static
RAM. A time-of-day alarm, three maskable interrupts
with a common interrupt output, and a programmable
square-wave output are available. The DS12R885 also
operates in either 24-hour or 12-hour format with an
AM/PM indicator. A precision temperature-compensat-
ed circuit monitors the status of VCC. If a primary
power-supply failure is detected, the device automati-
cally switches to a backup supply. The backup supply
input supports either a rechargeable battery or a super
cap, and includes an integrated trickle charger. The
trickle charger is always enabled. The DS12R885 is
accessed through a multiplexed address/data bus that
supports Intel and Motorola modes.
The DS12R887 is a surface-mount package using the
DS12R885 die, a 32.768kHz crystal, and a recharge-
able battery. The device provides a real-time clock/cal-
endar, one time-of-day alarm, three maskable interrupts
with a common interrupt output, a programmable
square wave, and 114 bytes of nonvolatile, battery-
backed static RAM. The date at the end of the month is
automatically adjusted for months with fewer than 31
days, including correction for leap years. It also oper-
ates in either 24-hour or 12-hour format with an AM/PM
indicator. A precision temperature-compensated circuit
monitors the status of VCC. If a primary power failure is
detected, the device automatically switches to a back-
up battery included in the package. The device is
accessed through a multiplexed byte-wide interface,
which supports both Intel and Motorola modes.
The DS12CR887 EDIP integrates a DS12R885 die with
a crystal and battery. The charging circuit on the
DS12R885 die is disabled. The battery has sufficient
capacity to power the oscillator and registers for five
years in the absence of VCC at +25°C.
The DS12R887 BGA includes a crystal and a recharge-
able battery. A fully charged battery can power the oscil-
lator and registers (typical current at +25°C) in the
absence of VCC for approximately 11 days (10% of
capacity consumed) or 98 days (90% capacity con-
sumed). When the discharge depth is 10% of capacity,
the battery can be recharged up to 1,000 times. If the dis-
charge depth is 90% of capacity, the battery can be
recharged up to 30 times. Thus, the life of the device
would be approximately 30 years (11 days X 1,000
cycles) or 8 years (98 days x 30 cycles). Charging time to
full capacity is approximately two days with VCC applied.
Please consult related application notes for detailed
information on battery lifetime versus depth of dis-
charge, and expected product lifetime based upon
battery cycles.
Oscillator Circuit
The DS12R885 uses an external 32.768kHz crystal. The
oscillator circuit does not require any external resistors
or capacitors to operate. Table 1 specifies several crys-
tal parameters for the external crystal. Figure 1 shows a
functional schematic of the oscillator circuit. An enable
bit in the control register controls the oscillator.
Oscillator startup times are highly dependent upon
crystal characteristics, PC board leakage, and layout.
High ESR and excessive capacitive loads are the major
contributors to long startup times. A circuit using a
crystal with the recommended characteristics and
proper layout usually starts within one second.
COUNTDOWN
CHAIN
X1
X2
CRYSTAL
CL1CL2
RTC REGISTERS
DS12R885
Figure 1. Oscillator Circuit Showing Internal Bias Network
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Nominal
Frequency
fO
32.768
kHz
Series
Resistance
ESR
50
k
Load
Capacitance
CL
12.5
pF
Table 1. Crystal Specifications*
*
The crystal, traces, and crystal input pins should be isolated
from RF generating signals. Refer to Application Note 58:
Crystal Considerations with Dallas Real-Time Clocks (RTCs)
for
additional specifications.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS12CR887-5+ | 功能描述:實(shí)時時鐘 RTC w/Constant V Trickle Charger RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS12R885-33 | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 114BYTE - Bulk |
| DS12R885-5 | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 114BYTE - Bulk |
| DS12R885S-33 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| DS12R885S-33/T&R | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 114BYTE 24SOIC W - Tape and Reel |
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