19-3475; Rev 0; 10/04
Silicon Oscillator with Reset Output
General Description
The MAX7376 silicon oscillator with reset, is a replace-
ment for ceramic resonators, crystals, crystal oscillator
modules, and discrete reset circuits. The MAX7376 pro-
vides the primary clock source and reset function for
microcontrollers in 3V, 3.3V, and 5V applications. The
MAX7376 features a factory-programmed high-speed
oscillator and a microprocessor (µP) power-on-reset
(POR) supervisor.
Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7376 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 MAX7376
is a good choice for demanding home appliance,
industrial, and automotive environments.
The MAX7376 is available in factory-programmed fre-
quencies from 32.768kHz to 10MHz. See Table 2 for
standard frequencies and contact the factory for cus-
tom frequencies.
The MAX7376 is available in a 5-pin SOT23 package.
Refer to the MAX7382 data sheet for frequencies
≥10MHz.
The MAX7376 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 Oscillator: 600kHz to 10MHz or 32kHz
♦
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% Duty Cycle
♦
5ns Output Rise and Fall Time
♦
Low Jitter: 160ps
P-P
)
at 8MHz (No PLL)
♦
3mA Operating Current (8MHz)
♦
13µA Operating Current (32kHz)
♦
-40°C to +125°C Temperature Range
Features
MAX7376
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
RESET
OUTPUT
Open drain
Active high
push-pull
Active low
push-pull
MAX7376C_ _ _-T
-40°C to +125°C 5 SOT23-5
MAX7376A_ _ _-T
MAX7376B_ _ _-T
-40°C to +125°C 5 SOT23-5
-40°C to +125°C 5 SOT23-5
Applications
White Goods
Automotive
Consumer Products
Appliances and Controls
Handheld Products
Portable Equipment
Microcontroller (µC) Systems
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.
Pin Configuration
TOP VIEW
CLOCK
1
5
E.C.
Typical Application Circuit appears at end of data sheet.
GND 2
MAX7376
RST/RST 3
4
V
CC
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 Reset Output
MAX7376
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
CLOCK OUTPUT
Minimum Operating Voltage
V
CC
= 4.5V, I
SOURCE
= 9mA
Output High Voltage
V
OH
V
CC
= 2.7V, I
SOURCE
= 2.5mA
Output Low Voltage
Initial Frequency Accuracy
Frequency Temperature
Sensitivity
Initial Frequency Accuracy
(32.768kHz)
Frequency Temperature
Sensitivity
CLOCK Output Duty Cycle
CLOCK Output Jitter
CLOCK Output Rise Time
CLOCK Output Fall Time
t
R
t
F
Observation of 8MHz output for 20s using a
500MHz oscilloscope
10% to 90%
90% to 10%
f
CLOCK
V
OL
f
CLOCK
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
(Note 3)
V
CC
= 5V, T
A
= +25°C (Note 2)
V
CC
= 2.7V to 5.5V, T
A
= +25°C
32.768kHz (Note 3)
43
32.440
31.785
±50
50
160
5
5
-2
-4
±50
32.768
V
CC
- 0.4
V
V
CC
- 0.4
0.4
0.4
+2
+4
±325
33.096
33.751
±325
57
V
%
ppm/
o
C
kHz
ppm/
o
C
%
ps
P-P
ns
ns
1.65
V
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 Reset Output
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
RST/RST OUTPUT
T
A
= +25°C
Reset Threshold
V
TH+
V
CC
rising
T
A
= -40°C to +125°C
Reset Hysteresis
POR Delay
Output High Voltage
Output Low Voltage
Leakage Current
V
OH
V
OL
I
LEAK
V
THYS
V
HYST
= {(V
TH+
) - ( V
TH-
)}/(V
TH-
) x 100%
V
CC
rising from 0V to (V
TH
+ 200mV) in 1µs
V
CC
= 4.5V, I
SOURCE
= 9mA
V
CC
= 2.7V, I
SOURCE
= 2.5mA
V
CC
= 4.5V, I
SINK
= 20mA
V
CC
= 2.7V, I
SINK
= 10mA
V
CC
= 5.5V, V
RST
= 5.5V, open drain
V
CC
- 0.4
V
CC
- 0.4
0.4
0.4
1
V
TH
-
2%
V
TH
-
5%
2.0
100
V
TH
+
2%
V
V
TH
+
5%
%
µs
V
V
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX7376
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 3.
Note 3:
Guaranteed by design. Not production tested.
Typical Operating Characteristics
(V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
DUTY CYCLE
vs. TEMPERATURE
MAX7376 toc01
DUTY CYCLE
vs. SUPPLY VOLTAGE
MAX7376 toc02
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
CLOCK = 4MHz
MAX7376 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 = 4MHz
55
54
53
DUTY CYCLE (%)
52
51
50
49
48
47
46
45
4.3
4.6
4.9
5.2
CLOCK = 4MHz
1.5
5.5
0.5
-55
-30
-5
20
45
70
95
120
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
Silicon Oscillator with Reset Output
MAX7376
Typical Operating Characteristics (continued)
(V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7376 toc04
FREQUENCY
vs. SUPPLY VOLTAGE
MAX7376 toc05
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
MAX7376 toc06
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
4.3
4.6
4.9
5.2
CLOCK = 4MHz
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
4.10
5.5
4.3
4.6
4.9
5.2
5.5
-55
-30
-5
20
45
70
95
120
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
CLOCK OUTPUT WAVEFORM
(C
L
= 10pF)
MAX7376 toc07
CLOCK OUTPUT WAVEFORM
(C
L
= 50pF)
MAX7376 toc08
CLOCK OUTPUT WAVEFORM
(C
L
= 100pF)
MAX7376 toc09
CLOCK
CLOCK
CLOCK
f = 4MHz, C
L
= 10pF
40ns/div
f = 4MHz, C
L
= 50pF
40ns/div
f = 4MHz, C
L
= 100pF
40ns/div
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD
MAXIMUM TRANSIENT DURATION (µs)
MAX7376 toc10
1000
RESET OCCURS
ABOVE THE CURVE
100
RESET = 4.29V
10
0
200
400
600
800
1000
RESET THRESHOLD OVERDRIVE (mV)
4
_______________________________________________________________________________________
Silicon Oscillator with Reset Output
Pin Description
PIN
1
2
3
4
5
NAME
CLOCK
GND
RST
V
CC
E.C.
Push-Pull Clock Output
Ground
Reset Output. See the
RST Reset Output Options
section for more details.
Positive Supply Voltage. Bypass V
CC
to GND with a 0.1µF capacitor.
Must Be Externally Connected to V
CC
FUNCTION
MAX7376
Detailed Description
The MAX7376 is a clock generator with integrated reset
for µCs and UARTs in 3V, 3.3V, and 5V applications
(Figure 1). The MAX7376 is a replacement for crystal
oscillator modules, crystals, or ceramic resonators and
a system-reset IC. The clock frequency is factory
trimmed to specific values. A variety of popular stan-
dard frequencies are available (Table 2). No external
components are required for setting or adjusting the
frequency.
Oscillator
The clock output is a push-pull configuration and is
capable of driving a ground-connected 500Ω or a posi-
tive-supply-connected 250Ω load to within 400mV of
either supply rail. The clock output remains stable over
the full operating voltage range and does not generate
short output cycles during either power-on or power-off.
A typical startup characteristic is shown in the
Typical
Operating Characteristics.
Applications Information
Interfacing to a µC Clock Input
The MAX7376 clock output is a push-pull, CMOS, logic
output that directly drives any µP or µC clock input.
There are no impedance-matching issues when using
the MAX7376. The MAX7376 is not sensitive to its posi-
tion on the board and it does not need to be placed right
next to the µP. Refer to the µC data sheet for clock-input
compatibility with external clock signals. The MAX7376
requires no biasing components or load capacitance.
When using the MAX7376 to retrofit a crystal oscillator,
remove all biasing components from the oscillator input.
Supply Voltage
The MAX7376 has been designed for use in systems
with nominal supply voltages of 3V, 3.3V, or 5V and is
specified for operation with supply voltages in the 2.7V
to 5.5V range. See the
Absolute Maximum Ratings
sec-
tion for limit values of power-supply and pin voltages.
V
CC
RST Reset Output Options
The MAX7376 is available with three reset output stage
options: push-pull with active-low output, push-pull with
active-high output, and open drain with active-low out-
put. The RST output is asserted when the monitored
input (V
CC
) drops below the internal V
TH-
threshold and
remains asserted for 100µs after the monitored input
exceeds the internal V
TH+
threshold. The open-drain
RST output requires an external pullup resistor.
BIAS_V
LOGIC
POR
RST/RST
MUX
CLOCK
Output Jitter
The MAX7376’s jitter performance is given in the
Electrical Characteristics
table as a peak-to-peak value
obtained by observing the output of the MAX7376 for
20s with a 500MHz oscilloscope. Jitter values are
approximately proportional to the period of the output
frequency of the device. Thus, a 4MHz part has
approximately twice the jitter value of an 8MHz part.
The jitter performance of clock sources degrades in the
presence of mechanical and electrical interference.
5
600kHz TO 10MHz
MAX7376
Figure 1. Functional Diagram
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