MAX6902ETA+T Maxim Integrated Products, MAX6902ETA+T Datasheet - Page 4

• Manufacturer Part Number: MAX6902ETA+T
• Description: IC RTC SPI COMPAT 8-TDFN
• Manufacturer: Maxim Integrated Products
• Type: Clock/Calendar/NVSRAMr

Specifications of MAX6902ETA+T

• Memory Size: 31B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 2 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MAX6902ETA+TTR

SPI-Compatible RTC in a TDFN
4
(T
PIN
A
—
1
2
3
4
5
6
7
8
= +25°C, unless otherwise noted.)
_______________________________________________________________________________________
Typical Operating Characteristic
NAME
DOUT
SCLK
GND
V
DIN
CS
X2
X1
EP
10.0
CC
1.0
0.1
2.0
Serial Clock Input. SPI clock for DIN and
DOUT data transfers.
SPI Data Output
SPI Data Input
Ground
Chip Select Input. Active low for valid data
transfers.
Power-Supply Pin. Bypass V
with a 0.1µF capacitor.
External 32.768kHz Crystal
External 32.768kHz Crystal
Exposed Paddle. Internally connected to
GND. Connect to GND, but do not use as
the sole ground connection point or leave
unconnected.
2.5
TIMEKEEPING CURRENT
vs. SUPPLY VOLTAGE
3.0
SUPPLY VOLTAGE (V)
3.5
4.0
Pin Description
FUNCTION
4.5
5.0
CC
5.5
to GND
The MAX6902 is a real-time clock/calendar with an SPI-
compatible interface and 31 x 8 bits of SRAM. It pro-
vides seconds, minutes, hours, day of the week, date of
the month, month, and year information, held in seven 8-
bit timekeeping registers (Functional Diagram). An on-
chip 32.768kHz oscillator circuit requires only a single
external crystal to operate. Table 1 specifies the para-
meters for the external crystal, and Figure 1 shows a
functional schematic of the oscillator circuit. The
MAX6902’s register addresses and definitions are
described in Figure 2 and in Table 2. Time and calendar
data are stored in the registers in binary-coded decimal
(BCD) format. A polled alarm function is included for
scheduled timing of user-defined times or intervals.
Table 1. Acceptable Quartz Crystal
Parameters
Figure 1. Crystal Oscillator Circuit Schematic
PARAMETER
Frequency
Equivalent
Series
Resistance
(ESR)
Parallel Load
Capacitance
Q Factor
25pF
MAX6902
SYMBOL
R
C
Q
f
S
L
X1
Detailed Description
EXTERNAL
CRYSTAL
40,000
11.2
MIN
40
32.768
X2
TYP
12.5
60,000
25pF
MAX
13.7
60
UNITS
kHz
kΩ
pF