DS1284/DS1286
PIN DESCRIPTION
PIN
NAME
FUNCTION
DIP
EDIP
PLCC
Active-Low Interrupt Output A. This open-drain pin requires a
pullup resistor for proper operation.
1
1
1
INTA
Connections for Standard 32.768kHz Quartz Crystal. The internal
oscillator circuitry is designed for operation with a crystal having
a specified load capacitance (CL) of 6pF. The crystal is connected
directly to the X1 and X2 pins. There is no need for external
capacitors or resistors. For more information on crystal selection
and crystal layout considerations, refer to Application Note 58:
Crystal Considerations with Dallas Real Time Clocks.
2, 3
—
2, 3
X1, X2
2, 3, 4,
21, 24,
25
4
4
N.C.
No Connection
Address Inputs
5–10
11, 12,
13, 15,
16–19
14, 21
20
5–10
11, 12,
13, 15,
16–19
14
5–10
11, 12,
13, 15,
16–19
14, 21
20
A5–A0
DQ0, DQ1,
DQ2, DQ3, Data Input/Output
DQ4–DQ7
GND
Ground
20
22
CE
Active-Low Chip-Enable Input
Active-Low Output-Enable Input
Square-Wave Output. Push-pull output. High impedance when
22
22
OE
23
23
23
SQW
VCC is below VTP.
Active-Low RAM Clear. Used to clear (set to logic 1) all 50
bytes of user NV RAM, but does not affect the registers
involved with time, alarm, and watchdog functions. To clear the
RAM, RCLR must be forced to an input logic 0 (-0.3V to
+0.8V) during battery-backup mode when VCC is not applied.
The RCLR function is designed to be used via human interface
(shorting to ground or by switch) and not be driven with external
buffers. This pin is internally pulled up and should be left
floating when not in use.
24
—
24
RCLR
Input for Any Standard 3V Lithium Cell or Other Energy
Source. Input voltage must be held between the minimum and
maximum limits for proper operation. The supply should be
connected directly to the VBAT pin. A diode must not be placed
in series with the battery to the VBAT pin. Furthermore, a diode is
not necessary because reverse charging current-protection
circuitry is provided internal to the device and has passed the
requirements of Underwriters Laboratories for UL listing. This
pin should be grounded but can be left floating.
25
—
25
VBAT
Active-Low (Active-High) Interrupt Output B. When the active-
high state is selected (IBH = 1), an open-drain pullup transistor
connected to VCC sources current when the output is active.
When the active-low state is selected (IBH = 0), an open-drain
pulldown transistor connected to ground sinks current when the
output is active. If active-high output operation is selected, a
pulldown resistor is required for proper operation. When active-
low output operation is selected, a pullup resistor is required for
proper operation.
INTB
(INTB)
26
27
26
27
26
27
WE
Active-Low Write-Enable Input
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DALLAS [ DALLAS SEMICONDUCTOR ]
