MAX7389_06 Datasheet, PDF (1/11 Pages) Maxim Integrated Products – Microcontroller Clock Generator with Watchdog

19-3897; Rev 1; 2/06
Microcontroller Clock Generator with
Watchdog
General Description
The MAX7389/MAX7390 replace ceramic resonators,
crystals, and supervisory functions for microcontrollers
in 3.3V and 5V applications.
The MAX7389/MAX7390 provide a clock source, reset,
and watchdog functions. The watchdog timer is pin pro-
grammable and provides watchdog timeout values in
the 16ms to 2048ms range. The MAX7389 provides a
separate watchdog output that is used as a status indi-
cator or to control safety-critical system elements.
The MAX7390 features a clock-speed select that
reduces the output frequency by half. This functionality
allows the microcontroller to operate at reduced power
and may be used to extend the time available to per-
form housekeeping tasks, such as writing data to flash
during a power failure.
The MAX7389/MAX7390 clock outputs are factory pro-
grammed to a frequency in the 1MHz to 16MHz range.
Four standard frequencies are available. Other frequen-
cies are available upon request. The maximum operating
supply current is 5.5mA with a clock frequency of 12MHz.
Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7389/MAX7390 are resistant to EMI
and vibration, and operate reliably at high tempera-
tures. The high-output drive current and absence of
high-impedance nodes make the oscillator invulnerable
to dirty or humid operating conditions.
The MAX7389/MAX7390 are available in an 8-pin µMAX^®
package. The MAX7389/MAX7390 standard operating
temperature range is from -40°C to +125°C.
White Goods
Automotive
Appliances and Controls
Applications
Handheld Products
Portable Equipment
Microcontroller Systems
µMAX is a registered trademark of Maxim Integrated Products, Inc.
TOP VIEW
V_CC 1
WDS1 2
WDS2 3
GND 4
MAX7389
8 CLOCK
7 RST/RST
6 WDI
5 WDO
Features
♦ Robust Microcontroller Clock and Supervisor in a
Single Package
♦ Integrated Reset and Watchdog Functions
♦ Pin-Programmable Watchdog Timeout
♦ Speed Select
♦ +2.7V to +5.5V Operation
♦ Factory-Trimmed Oscillator
♦ Reset Valid Down to 1.1V Supply Voltage
♦ ±10mA Clock-Output Drive Current
♦ ±4% Total Accuracy for -40°C to +125°C
♦ ±2.75% Total Accuracy for 0°C to +85°C
♦ 5.5mA Operating Current (12MHz Version)
♦ -40°C to +125°C Temperature Range
♦ 8-Pin µMAX Surface-Mount Package
♦ 1MHz to 16MHz Factory Preset Frequency
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX7389srff
MAX7390srff
-40^oC to +125^oC 8 µMAX
-40^oC to +125^oC 8 µMAX
U8-1
U8-1
Note: “s” is a placeholder for the reset output type. Insert the
symbol found in Table 3 in the place of “s.” “r” is a placeholder
for the power-on reset (POR) voltage. Insert the symbol found in
Table 2 in the place of “r.” “ff” is a placeholder for the nominal
output frequency. Insert the symbol found in Table 4 in the
place of “ff.” For example, MAX7389CMTP describes a device
with 4.38V reset level, open-collector RST output, and a clock
output frequency of 8MHz.
Typical Application Circuit, Functional Diagram, and Selector
Guide appear at end of data sheet.
TOP VIEW
V_CC 1
WDS1 2
WDS2 3
GND 4
Pin Configurations
MAX7390
8 CLOCK
7 RST/RST
6 WDI
5 SPEED
µMAX
µMAX
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