DS1677 반도체 회로 부품 판매점
Portable System Controller
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 Dallas Semiconductor |
www.DataSheet4U.com
DS1677
Portable System Controller
www.dalsemi.com
FEATURES
Provides Real Time Clock:
- Counts seconds, minutes, hours, date of
the month, month, day of the week, and
year with leap year compensation valid up
to 2100
- Power control circuitry supports system
power on from day/time alarm
Microprocessor monitor:
- Halts microprocessor during power–fail
- Automatically restarts microprocessor
after power failure
- Monitors push–button for external
override
- Halts and resets an out of control
microprocessor
=NV RAM control:
- Automatic battery backup and write
protection to external SRAM
3–channel, 8–bit analog–to–digital converter
Simple 3–wire interface
+5.0V operation
=1.25V threshold detector for power–fail
warning
PIN ASSIGNMENT
VBAT
VCCO
SCLK
I/O
CS
CEI
CEO
NC
INT
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
20-Pin TSSOP
ST
VCC
X1
X2
AIN0
AIN1
AIN2
RST
PFI
PFO
ORDERING INFORMATION
DS1677E 20–Pin TSSOP
DESCRIPTION
The Portable System Controller is a circuit which incorporates many of the functions necessary for low
power portable products integrated into one chip. The DS1677 provides a Real Time Clock, NV RAM
controller, micro-processor monitor, power–fail warning, and a 3–channel, 8–bit analog–to–digital
converter. Communication with the DS1677 is established through a simple 3–wire interface.
The Real Time Clock (RTC) provides seconds, minutes, hours, day, date, month, and year information
with leap year compensation. The RTC also provides an alarm interrupt. This interrupt works when the
DS1677 is powered by the system power supply or when in battery backup operation so the alarm can be
used to wake up a system that is powered down.
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DS1677
Automatic backup and write protection of an external SRAM is provided through the VCCO and CE0 pins.
The backup energy source used to power the RTC is also used to retain RAM data in the absence of VCC
through the VCCO pin. The chip-enable output to SRAM, CE0 , is controlled during power transients to
prevent data corruption.
The microprocessor monitor circuitry of the DS1677 provides three basic functions. First, a precision
temperature–compensated reference and comparator circuit monitors the status of VCC. When an out–of–
tolerance condition occurs, an internal power–fail signal is generated which forces the to RST the active
state. When VCC returns to an in–tolerance condition, the RST signal is kept in the active state for
250 ms to allow the power supply and processor to stabilize. The DS1677 debounces a push–button input
and guarantees an active RST pulse width of 250 ms. The third function is a watchdog timer. The
DS1677 has an internal timer that forces the RST signal to the active state if the strobe input is not driven
low prior to watchdog time–out.
The DS1677 also provides a 3–channel 8–bit successive approximation analog–to–digital converter. The
converter has an internal 2.55 volt (typical) reference voltage generated by an on–board band–gap circuit.
The A/D converter is monotonic (no missing codes) and has an internal analog filter to reduce high
frequency noise.
OPERATION
The block diagram in Figure 1 shows the main elements of the DS1677. The following paragraphs
describe the function of each pin.
DS1677 BLOCK DIAGRAM Figure 1
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제조업체: Dallas Semiconductor
( dallas )
DS1677 controller
데이터시트 다운로드 :
[ DS1677.PDF ]
[ DS1677 다른 제조사 검색 ]
국내 전력반도체 판매점
상호 : 아이지 인터내셔날
전화번호 : 051-319-2877
[ 홈페이지 ]
IGBT, TR 모듈, SCR, 다이오드모듈, 각종 전력 휴즈
( IYXS, Powerex, Toshiba, Fuji, Bussmann, Eaton )
전력반도체 문의 : 010-3582-2743
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