19-3474; Rev 0; 10/04
Silicon Oscillator with Low-Power
Frequency Switching
General Description
The MAX7377 dual-speed silicon oscillator with reset is
a replacement for ceramic resonators, crystals, crystal
oscillator modules, and discrete reset circuits. The
device provides the primary and secondary clock
source for microcontrollers in 3V, 3.3V, and 5V applica-
tions. The MAX7377 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 MAX7377 is resistant to vibration and EMI.
The high-output-drive current and absence of high-
impedance nodes make the oscillator less susceptible
to dirty or humid operating conditions. With a wide
operating temperature range as standard, the MAX7377
is a good choice for demanding home appliance,
industrial, and automotive environments.
The MAX7377 is available in factory-programmed fre-
quencies from 32.768kHz to 10MHz. See Table 1 for
standard frequencies and contact the factory for cus-
tom frequencies.
The MAX7377 is available in a 5-pin SOT23 package.
Refer to the MAX7383 data sheet for frequencies
≥10MHz.
The MAX7377 standard operating tempera-
ture range is -40°C to +125°C. See the
Applications
Information
section for the extended operating temper-
ature range.
♦
2.7V to 5.5V Operation
♦
Accurate High-Speed 600kHz to 10MHz Oscillator
♦
Accurate Low-Speed 32kHz Oscillator
♦
Glitch-Free Switch Between High Speed and Low
Speed at Any Time
♦
±10mA
Clock-Output Drive Capability
♦
2% Initial Accuracy
♦
±50ppm/°C
Temperature Coefficient
♦
50% Duty Cycle
♦
5ns Output Rise and Fall Time
♦
Low Jitter: 160ps
(P-P)
at 8MHz (No PLL)
♦
3mA Fast-Mode Operating Current (8MHz)
♦
13µA Slow-Mode Operating Current (32kHz)
♦
-40°C to +125°C Temperature Range
Features
MAX7377
Ordering Information
PART
MAX7377AX_ _-T
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
5 SOT23-5
The first two letters are AX. See Table 1 at the end of the data
sheet for the two-letter code.
Applications
White Goods
Handheld Products
Automotive
Portable Equipment
Consumer Products
Microcontroller Systems
Appliances and Controls
TOP VIEW
CLOCK
1
5
E.C.
Pin Configuration
GND 2
MAX7377
SPEED 3
4
V
CC
Typical Application Circuit appears at end of data sheet.
SOT23
________________________________________________________________
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
MAX7377
ABSOLUTE MAXIMUM RATINGS
V
CC
to 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)
5-Pin SOT23
(derate 7.1mW/°C above +70°C) ...................571mW (U5 - 2)
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
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
(V
CC
= 2.7V to 5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Note 1)
PARAMETER
Operating Supply Voltage
Operating Supply Current
LOGIC INPUT (SPEED)
Input High Voltage
Input Low Voltage
Input Current
CLOCK OUTPUT
V
CC
= 4.5V, I
SOURCE
= 9mA
Output High Voltage
V
OH
V
CC
= 2.7V, I
SOURCE
= 2.5mA
Output Low Voltage
Initial Fast CLOCK Frequency
Accuracy
V
OL
f
FCLOCK
V
CC
= 4.5V, I
SINK
= 20mA
V
CC
= 2.7V, I
SINK
= 10mA
V
CC
= 5V, T
A
= +25°C (Note 2)
V
CC
= 2.7V to 5.5V, T
A
= +25°C
-2
-4
V
CC
- 0.4
V
V
CC
- 0.4
0.4
0.4
+2
+4
V
%
V
IH
V
IL
I
IN
0.7 x
V
CC
0.3 x
V
CC
2
V
V
µA
SYMBOL
V
CC
I
CC
f
CLOCK
= 8MHz, no load
f
CLOCK
= 32.768kHz, no load
CONDITIONS
MIN
2.7
3
13
TYP
MAX
5.5
5
25
UNITS
V
mA
µA
2
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 2.7V to 5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Note 1)
PARAMETER
Fast CLOCK Frequency
Temperature Sensitivity
Initial Slow CLOCK Frequency
Accuracy
Slow CLOCK Frequency
Temperature Sensitivity
CLOCK Output Duty Cycle
CLOCK Output Jitter
CLOCK Output Rise Time
CLOCK Output Fall Time
Startup Delay
Output Undervoltage Lockout
Output Undervoltage Lockout
Hysteresis
UVLO
V
THYS
t
R
t
F
Observation of 8MHz output for 20s using a
500MHz oscilloscope
10% to 90%
90% to 10%
V
CC
rising from 0 to 5V in 1µs
V
CC
rising
T
A
= +25°C
T
A
= -40°C to +125°C
2.15
2.05
45
f
SCLOCK
SYMBOL
(Note 3)
V
CC
= 5V, T
A
= +25°C (Note 2)
V
CC
= 2.7V to 5.5V, T
A
= +25°C
(Note 3)
43
32.440
31.785
±50
50
160
5
5
100
2.2
2.25
2.35
CONDITIONS
MIN
TYP
±50
32.768
MAX
±325
33.096
33.751
±325
57
UNITS
ppm/
o
C
kHz
ppm/
o
C
%
ps
P-P
ns
ns
µs
V
mV
MAX7377
Note 1:
All parameters are tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
Note 2:
The frequency is determined by part number selection. See Table 1.
Note 3:
Guaranteed by design. Not production tested.
_______________________________________________________________________________________
3
Silicon Oscillator with Low-Power
Frequency Switching
MAX7377
Typical Operating Characteristics
(V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
DUTY CYCLE vs. TEMPERATURE
MAX7377 toc01
DUTY CYCLE vs. TEMPERATURE
MAX7377 toc02
DUTY CYCLE vs. SUPPLY VOLTAGE
54
53
DUTY CYCLE (%)
52
51
50
49
48
47
46
45
CLOCK = 32kHz
MAX7377 toc03
55
54
53
DUTY CYCLE (%)
52
51
50
49
48
47
46
45
-55
-30
-5
20
45
70
95
120
TEMPERATURE (°C)
CLOCK = 32kHz
55
54
53
DUTY CYCLE (%)
52
51
50
49
48
47
46
45
55
CLOCK = 4MHz
-55
-30
-5
20
45
70
95
120
4.3
4.6
4.9
5.2
5.5
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
DUTY CYCLE vs. SUPPLY VOLTAGE
MAX7377 toc04
SUPPLY CURRENT vs. TEMPERATURE
MAX7377 toc05
SUPPLY CURRENT vs. TEMPERATURE
1.4
1.3
SUPPLY CURRENT (mA)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
CLOCK = 4MHz
MAX7377 toc06
55
54
53
DUTY CYCLE (%)
52
51
50
49
48
47
46
45
CLOCK = 4MHz
14.0
CLOCK = 32kHz
13.5
SUPPLY CURRENT (µA)
13.0
12.5
12.0
11.5
11.0
10.5
10.0
1.5
4.3
4.6
4.9
5.2
5.5
-55
-30
-5
20
45
70
95
120
-55
-30
-5
20
45
70
95
120
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX7377 toc07
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX7377 toc08
FREQUENCY vs. SUPPLY VOLTAGE
34.5
34.0
FREQUENCY (kHz)
33.5
33.0
32.5
32.0
31.5
31.0
30.5
30.0
CLOCK = 32kHz
MAX7377 toc09
30
CLOCK = 32kHz
25
SUPPLY CURRENT (µA)
20
15
10
5
0
4.3
4.6
4.9
5.2
1.5
1.4
1.3
SUPPLY CURRENT (mA)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
35.0
CLOCK = 4MHz
5.5
4.3
4.6
4.9
5.2
5.5
4.3
4.6
4.9
5.2
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
MAX7377
Typical Operating Characteristics (continued)
(V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
FREQUENCY vs. SUPPLY VOLTAGE
MAX7377 toc10
FREQUENCY vs. TEMPERATURE
MAX7377 toc11
FREQUENCY vs. TEMPERATURE
4.08
4.06
FREQUENCY (MHz)
4.04
4.02
4.00
3.98
3.96
3.94
3.92
3.90
CLOCK = 4MHz
MAX7377 toc12
4.10
4.08
4.06
FREQUENCY (MHz)
4.04
4.02
4.00
3.98
3.96
3.94
3.92
3.90
CLOCK = 4MHz
33.0
32.9
32.8
FREQUENCY (kHz)
32.7
32.6
32.5
32.4
32.3
32.2
32.1
32.0
CLOCK = 32kHz
4.10
4.3
4.6
4.9
5.2
5.5
-55
-30
-5
20
45
70
95
120
-55
-30
-5
20
45
70
95
120
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
CLOCK OUTPUT WAVEFORM (C
L
= 10pF)
MAX7377 toc13
CLOCK OUTPUT WAVEFORM (C
L
= 50pF)
MAX7377 toc14
CLOCK OUTPUT WAVEFORM (C
L
= 100pF)
MAX7377 toc15
CLOCK
CLOCK
CLOCK
f = 4MHz, C
L
= 10pF
40ns/div
f = 4MHz, C
L
= 50pF
40ns/div
f = 4MHz, C
L
= 100pF
40ns/div
HIGH-SPEED TO LOW-SPEED
TRANSITION
MAX7377 toc16
HIGH-SPEED TO LOW-SPEED
TRANSITION (EXPANDED SCALE)
MAX7377 toc17
20µs/div
400ns/div
_______________________________________________________________________________________
5
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