19-3492; Rev 0; 1/05
Silicon Oscillator with Low-Power
Frequency Switching
General Description
The MAX7383 dual-speed silicon oscillator replaces
ceramic resonators, crystals, and crystal-oscillator
modules as the primary and secondary clock source for
microcontrollers in 3V, 3.3V, and 5V applications. The
MAX7383 features a factory-programmed high-speed
oscillator, a 32.768kHz oscillator, and a clock-selector
input. The clock output can be switched at any time
between the high-speed clock and the 32.768kHz clock
for low-power operation. Switchover is synchronized
internally to provide glitch-free clock switching.
Unlike typical crystal and ceramic-resonator oscillator
circuits, the MAX7383 is resistant to vibration and EMI.
The high-output-drive current and absence of high-
impedance nodes makes the oscillator less susceptible
to dirty or humid operating conditions. With a wide
operating temperature range as standard, the
MAX7383 is a good choice for demanding home appli-
ance and automotive environments.
The MAX7383 is available with factory-programmed fre-
quencies ranging from 10MHz to 32MHz. See Table 1
for standard frequencies and contact the factory for
custom frequencies. Refer to the MAX7377 data sheet
for frequencies less than 10MHz.
The MAX7383 is available in a 5-pin SOT23 package.
The MAX7383 standard operating temperature range is
-40°C to +125°C. See the
Applications Information
sec-
tion for extended operating temperature range.
♦
2.7V to 5.5V Operation
♦
High-Speed Oscillator from 10MHz to 32MHz
Low-Speed 32kHz Oscillator
Glitch-Free Clock-Speed Switching
♦
±10mA Clock-Output Drive Capability
♦
2.5% Initial Accuracy
♦
±50ppm/°C (typ) Frequency Drift
♦
50% Duty Cycle
♦
5ns Output Rise and Fall Time
♦
Low Jitter: 80ps
P-P
at 16MHz
♦
4mA Operating Current at 16MHz
♦
13µA, 32kHz Operating Current
♦
-40°C to +125°C Temperature Range
♦
Small 5-Pin SOT23 Package
Features
MAX7383
Ordering Information
PART*
TEMP RANGE
PIN-
PACKAGE
RESET
OUTPUT
Active high
push-pull
MAX7383AX _ _-T -40°C to +125°C 5 SOT23-5
Applications
White Goods
Automotive
Consumer Products
Appliances and Controls
Handheld Products
Portable Equipment
Microcontroller Systems
*The
first two letters are AX. Insert the two-letter code from
Table 2 in the remaining two positions for the desired frequen-
cy range. Insert the two-letter code from Table 1 in the remain-
ing two positions for the desired frequency range. Table 1 is
located at the end of the data sheet.
Typical Operating Circuit
V
CC
2.7V TO 5.5V
0.1µF
V
CC
CLOCK
OSC1
OSC2
MAX7383
E.C.
I/O PORT
SPEED
GND
µC
Pin Configuration appears at end of data sheet.
________________________________________________________________
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.
Silicon Oscillator with Low-Power
Frequency Switching
MAX7383
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ...........................................................-0.3V to +6.0V
All Other Pins to GND...................................-0.3V to (V+ + 0.3V)
CLOCK Current ...............................................................±50mA
Input Current (SPEED)......................................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)....571mW (U5-2)
Operating Temperature Range .........................-55°C to +135°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
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.
ELECTRICAL CHARACTERISTICS
(Typical
Operating Circuit,
V
CC
= 2.7V to 5.5V, V
L
= V
CC
, T
A
= -40°C to +125°C. Typical values are at V
CC
= 5.0V, T
A
= +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Operating Supply Voltage
SYMBOL
V
CC
f
CLOCK
= 16MHz, T
A
= -40°C to +125°C, no
load
f
CLOCK
= 14.7456MHz, T
A
= -40°C to
+125°C, no load
f
CLOCK
= 12MHz, T
A
= -40°C to +125°C, no
load
Operating Supply Current
I
CC
f
CLOCK
= 11.0592MHz, T
A
= -40°C to
+125°C, no load
f
CLOCK
= 10MHz, T
A
= -40°C to +125°C, no
load
f
CLOCK
= 32.768kHz, T
A
= -40°C to
+125°C, no load
LOGIC INPUTS (SPEED)
Input High Voltage
Input Low Voltage
Input Current
CLOCK OUTPUT
Output High Voltage
Output Low Voltage
V
OH
V
OL
V
L
= 4.5V, I
SOURCE
= 7.0mA
V
L
= 2.7V, I
SOURCE
= 2.0mA
V
L
= 4.5V, I
SINK
= 20mA
V
L
= 2.7V, I
SINK
= 10mA
V
CC
= 5V, T
A
= +25°C, deviation from
selected frequency
Fast Clock Frequency Accuracy
f
CLOCK
V
CC
= 2.7V to 5.5V, T
A
= +25°C,
deviation from selected frequency
T
A
= -40°C to +125°C
-2.5
-5.0
±50
V
L
- 0.4
0.4
+2.5
%
+3.5
±350
ppm/°C
V
V
V
IH
V
IL
I
IN
V
CC
SPEED = 5.5V
0.7 x V
CC
0.3 x V
CC
2
V
V
µA
13
CONDITIONS
MIN
2.7
TYP
MAX
5.5
8.7
8.0
6.5
6.0
5.4
25
µA
mA
UNITS
V
Fast Clock Temperature
Coefficient
2
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
ELECTRICAL CHARACTERISTICS (continued)
(Typical
Operating Circuit,
V
CC
= 2.7V to 5.5V, V
L
= V
CC
, T
A
= -40°C to +125°C. Typical values are at V
CC
= 5.0V, T
A
= +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Slow Clock Frequency
Slow Clock Temperature
Coefficient
Duty Cycle
Output Jitter
Output Rise Time
Output Fall Time
Undervoltage Lockout
Threshold
Undervoltage Lockout Hysteresis
t
R
t
F
V
TH
SYMBOL
f
CLOCK
CONDITIONS
V
CC
= 5V, T
A
= +25°C
V
CC
= 2.7V to 5.5V, T
A
= +25°C
T
A
= -40°C to +125°C
(Note 2)
Observation of 16MHz for 20s using a
500MHz oscilloscope
10% to 90%
90% to 10%
V
CC
rising, deviation
from nominal threshold
T
A
= +25°C
T
A
= -40°C to
+125°C
2.45
2.37
1
40
MIN
32.268
31.768
TYP
32.768
32.768
±50
50
80
5
5
2.55
2.63
%
MAX
33.268
33.768
±325
60
UNITS
kHz
ppm/°C
%
ps
P-P
ns
ns
MAX7383
HYST
Difference between rising and falling
thresholds
%
Note 1:
All parameters tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
Note 2:
Guaranteed by design. Not production tested.
Typical Operating Characteristics
(V
CC
= V
L
= 5V, T
A
= +25°C, frequency = 10MHz, unless otherwise noted.)
DUTY CYCLE vs. TEMPERATURE
MAX7383 toc01
DUTY CYCLE vs. SUPPLY VOLTAGE
FREQUENCY = 11.0592MHz
50
DUTY CYCLE (%)
49
48
47
46
45
MAX7383 toc02
SUPPLY CURRENT vs. TEMPERATURE
MAX7383 toc03
50.5
51
3.25
3.20
SUPPLY CURRENT (mA)
3.15
3.10
FREQUENCY = 10MHz
3.05
3.00
2.95
2.90
50.0
DUTY CYCLE (%)
49.5
FREQUENCY = 10MHz
49.0
48.5
48.0
-55
-17
21
59
97
135
TEMPERATURE (°C)
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-55
-17
21
59
97
135
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Silicon Oscillator with Low-Power
Frequency Switching
MAX7383
Typical Operating Characteristics (continued)
(V
CC
= V
L
= 5V, T
A
= +25°C, frequency = 10MHz, unless otherwise noted.)
FREQUENCY DEVIATION
vs. SUPPLY VOLTAGE
FREQUENCY = 11.0592MHz
1.5
FREQUENCY DEVIATION (%)
1.0
0.5
0
-0.5
-1.0
-1.5
1.5
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
SUPPLY VOLTAGE (V)
-2.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
SUPPLY VOLTAGE (V)
MAX7383 toc05
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX7383 toc04
FREQUENCY DEVIATION
vs. TEMPERATURE
FREQUENCY = 10MHz
3
FREQUENCY DEVIATION (%)
2
1
0
-1
-2
-3
-4
-55
-17
21
59
97
135
TEMPERATURE (°C)
MAX7383 toc06
MAX7383 toc09
MAX7383 toc12
MAX7383 toc11
4.0
FREQUENCY = 11.0592MHz
3.5
SUPPLY CURRENT (mA)
2.0
4
3.0
2.5
2.0
SETTLING TIME FROM START
MAX7383 toc07
CLOCK OUTPUT WAVEFORM
(C
L
= 10pF)
MAX7383 toc08
CLOCK OUTPUT WAVEFORM
(C
L
= 10pF)
CH1 FREQ
9.992MHz
LOW RESOLUTION
10µs/div
CHANNEL 1 = CLOCK, CHANNEL 2 = V
CC
20ns/div
20ns/div
CLOCK OUTPUT WAVEFORM
(C
L
= 100pF)
SUPPLY CURRENT vs. FREQUENCY
5
HIGH-SPEED TO LOW-SPEED
TRANSITION
MAX7383 toc10
SUPPLY CURRENT (mA)
4
3
2
1
20ns/div
10
11
12
13
14
15
16
10µs/div
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
FREQUENCY (MHz)
4
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
Typical Operating Characteristics (continued)
(V
CC
= V
L
= 5V, T
A
= +25°C, frequency = 10MHz, unless otherwise noted.)
HIGH-SPEED TO LOW-SPEED
TRANSITION (DETAIL ZOOM)
MAX7383 toc13
MAX7383
LOW-SPEED TO HIGH-SPEED
TRANSITION
MAX7383 toc14
LOW-SPEED TO HIGH-SPEED
TRANSITION (DETAIL ZOOM)
MAX7383 toc15
40ns/div
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
10µs/div
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
100ns/div
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
Pin Description
PIN
1
2
3
4
5
NAME
CLOCK
GND
SPEED
V
CC
E.C.
Push-Pull Clock Output
Ground
Clock Speed Select Input. Drive SPEED low to select the 32kHz fixed frequency. Drive SPEED high to
select the factory-trimmed frequency.
Positive Supply Voltage. Bypass V
CC
to GND with a 0.1µF capacitor.
Externally Connected. Connect to Vcc.
FUNCTION
_______________________________________________________________________________________
5
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