
General Description
The MAX7387/MAX7388 replace ceramic resonators,
crystals, and supervisory functions for microcontrollers
in 3.3V and 5V applications.
The MAX7387/MAX7388 provide a clock source together
with integrated reset, watchdog, and power-fail func-
tions. The watchdog timer is pin programmable and
provides watchdog timeout values in the 16ms to
2048ms range. The power-fail output provides early
warning of power failure. The power-fail threshold on the
MAX7388 is internally set. The MAX7387 also provides
a separate watchdog output that is used as a status
indicator or to control safety-critical system elements.
The MAX7387/MAX7388 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 (max) with a clock frequency of
12MHz.
Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7387/MAX7388 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 MAX7387/MAX7388 are available in 10-pin and 8-pin
MAX packages, respectively. The MAX7387/MAX7388
standard operating temperature range is from -40°C to
+125°C.
Applications
White Goods
Handheld Products
Automotive
Portable Equipment
Appliances and Controls
Microcontroller Systems
Features
Robust Microcontroller Clock and Supervisor in a
Single Package
Integrated Reset, Watchdog, and Power-Fail
Functions
Pin-Programmable Watchdog Timeout
+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
-40°C to +125°C Temperature Range
8- and 10-Pin MAX Surface-Mount Packages
5.5mA Operating Current (12MHz)
1MHz to 16MHz Factory Preset Frequency
MAX7387/MAX7388
System Monitoring Oscillator with
Watchdog and Power Fail
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
WDI
PFO
GND
1
2
8
7
CLOCK
RST/RST
WDS1
WDS2
VCC
TOP VIEW
3
4
6
5
MAX7388
MAX
Pin Configurations
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
PKG CODE
MAX7387srff -40
oC to +125oC 10 MAX
U10-2
MAX7388srff -40
oC to +125oC 8 MAX
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, MAX7387CMTP 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.
MAX is a registered trademark of Maxim Integrated Products, Inc.
1
2
3
4
5
10
9
8
7
6
CLOCK
RST/RST
WDI
PFO
WDS2
WDS1
VCC
PFI
MAX7387
TOP VIEW
MAX
WDO
GND