MAXIM MAX7378 User Manual

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General Description

The MAX7378 dual-speed silicon oscillator with reset, is
a replacement for ceramic resonators, crystals, crystal­oscillator modules, and discrete reset circuits. The
MAX7378 provides the primary and secondary clock
source and reset function for microcontrollers in 3V,

3.3V, and 5V applications. The MAX7378 features a
factory-programmed high-speed oscillator, a

32.768kHz oscillator, a clock selector input, and a
microprocessor (µP) power-on-reset (POR) supervisor.
The clock output can be switched at any time between
the high-speed clock and the 32.768kHz clock for low­power operation. Switchover is synchronized internally
to provide glitch-free clock switching.

Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7378 is resistant to vibration and EMI.
The high-output-drive current and absence of high­impedance nodes make the oscillator less susceptible
to dirty or humid operating conditions. With a wide
operating temperature range as standard, the
MAX7378 is a good choice for demanding home appli­ance, industrial, and automotive environments.

The MAX7378 is available in an 8-pin µMAX®package.
Refer to the MAX7384 data sheet for frequencies
≥10MHz. The MAX7378 standard operating tempera­ture range is -40°C to +125°C. See the Applications
Information section for the extended operating temper­ature range.

Applications

White Goods
Automotive
Consumer Products
Appliances and Controls
Handheld Products
Portable Equipment
Microcontroller (µC) Systems

Features

♦ 2.7V to 5.5V Operation
♦ Accurate High-Speed Oscillator: 600kHz to 10MHz
♦ Accurate Low-Speed 32kHz Oscillator
♦ Glitch-Free Switch Between High Speed and Low

Speed at Any Time

♦ Reset Output Holds the µC in Reset for 100µs

After Clock Startup

♦ ±10mA Clock-Output Drive Capability
♦ 2% Initial Accuracy
♦ ±50ppm/°C Temperature Coefficient
♦ 50% ±7% Output Duty Cycle
♦ 5ns Output Rise and Fall Time
♦ Low Jitter: 160ps

(Peak-to-Peak)

at 8MHz

♦ 2.4mA Fast-Mode Operating Current (8MHz)
♦ 11µA Slow-Mode Operating Current (32kHz)
♦ -40°C to +125°C Temperature Range

MAX7378

Silicon Oscillator with Low-Power

Frequency Switching and Reset Output

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3350; Rev 0; 7/04

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.

Pin Configuration appears at end of data sheet.

MAX7378

CLOCK

V

L

OSC1

OSC2

µCRST

I/O PORT

V

CC

SUPPLY VOLTAGE

ENABLE

RST/RST

SPEED

Typical Application Circuit

µMAX is a registered trademark of Maxim Integrated Products, Inc.

PART

TEMP RANGE

RESET

PIN-

PACKAGE

MAX7378A _ _ _

push-pull

8 µMAX

MAX7378B _ _ _

push-pull

8 µMAX

MAX7378C _ _ _

8 µMAX

Standard version is shown in bold. The first letter after the part
number designates the reset output option. Insert the letter cor­responding to the desired reset threshold level from Table 1 in
the next position. Insert the two-letter code from Table 2 in the
remaining two positions for the desired frequency range. See
Table 3 for standard part numbers.

OUTPUT

-40oC to +125oC

-40oC to +125oC

-40oC to +125oC Open drain

Active high

Active low

MAX7378

Silicon Oscillator with Low-Power
Frequency Switching and Reset Output

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 2.7V to 5.5V, VL= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= 5V, TA = +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

VCCto GND .............................................................-0.3V to +6V

All Other Pins to GND ................................-0.3V to (V

CC

+ 0.3V)

CLOCK Current ................................................................±10mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.5mW/°C above +70°C)....362mW (U8-1)

Operating Temperature Range .........................-40°C to +135°C

Junction Temperature .....................................................+150°C

Storage Temperature Range.............................-60°C to +150°C

Lead Temperature (soldering, 10s).................................+300°C

PARAMETER

CONDITIONS

UNITS

Operating Supply Voltage V

CC

2.7 5.5 V

Logic Output Supply Voltage V

L

Must be connected to V

CC

2.7 5.5 V

f

CLOCK

= 8MHz, no load 2.4 5.5 mA

Operating Supply Current

f

CLOCK

= 32.768kHz, no load 11 25 µA

Shutdown Current I

SHDN

ENABLE = 0V; ICC + I

L

3.0 7.5 µA

LOGIC INPUT (SPEED, ENABLE)

Input High Voltage V

IH

0.7 x
V

Input Low Voltage V

IL

0.3 x
V

Input Current I

IN

2µA

CLOCK OUTPUT

VL = 4.5V, I

SOURCE

= 9mA

V

L

-

0.4

Output High Voltage V

OH

VL = 2.7V, I

SOURCE

= 2.5mA

V

L

-

0.4

V

VL = 4.5V, I

SINK

= 20mA 0.4

Output Low Voltage V

OL

VL = 2.7V, I

SINK

= 10mA 0.4

V

VCC = 5V, TA = +25°C (Note 2) -2 +2

Initial Fast CLOCK Frequency
Accuracy

VCC = 2.7V to 5.5V, TA = +25°C -4 +4

%

Fast CLOCK Frequency
Temperature Sensitivity

(Note 3)

ppm/oC

VCC = 5V, TA = +25°C

Initial Slow CLOCK Frequency
Accuracy

VCC = 2.7V to 5.5V, TA = +25°C

kHz

Slow CLOCK Frequency
Temperature Sensitivity

(Note 3)

ppm/oC

SYMBOL

I

+ I

CC

I

+ I

CC

L

L

MIN TYP MAX

f

FCLOCK

f

SCLOCK

V

CC

32.440 32.768 33.096

31.785 33.751

±50 ±325

±50 ±325

V

CC

MAX7378

Silicon Oscillator with Low-Power

Frequency Switching and Reset Output

_______________________________________________________________________________________ 3

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2: The frequency is determined by part number selection. See the Ordering Information.
Note 3: Guaranteed by design. Not production tested.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 2.7V to 5.5V, VL= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= 5V, TA = +25°C.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

CLOCK Output Duty Cycle 43 50 57 %

CLOCK Output Jitter

Observation of 8MHz output for 20s using a
500MHz oscilloscope

ps

P-P

CLOCK Output Rise Time t

R

10% to 90% 5 ns

CLOCK Output Fall Time t

F

90% to 10% 5 ns

RST/RST OUTPUT

TA = +25°C

V

TH

-

VTH +

Reset Threshold V

TH+

VCC rising

T

A

= -40°C to +125°C

V

TH

-

5%

VTH +

5%

V

Reset Hysteresis V

THYS

V

HYST

= {(V

TH+

) - ( V

TH-

)}/(V

TH-

) x 100% 2.0 %

POR Delay

µs

VL = 4.5V, I

SOURCE

= 9mA VL - 0.4

Output High Voltage V

OH

VL = 2.7V, I

SOURCE

= 2.5mA VL - 0.4

V

VL = 4.5V, I

SINK

= 20mA 0.4

Output Low Voltage V

OL

VL = 2.7V, I

SINK

= 10mA 0.4

V

160

1.5%

VCC rising from 0V to (VTH +200mV) in 1µs 100

1.5%