19-3475; Rev 0; 10/04
Silicon Oscillator with Reset Output
Applications
White Goods
Automotive
Consumer Products
Appliances and Controls
Handheld Products
Features
♦ 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: 160psP-P) at 8MHz (No PLL)
♦ 3mA Operating Current (8MHz)
♦ 13µA Operating Current (32kHz)
♦ -40°C to +125°C Temperature Range
Ordering Information
PART
TEMP RANGE
PINPACKAGE
RESET
OUTPUT
MAX7376C_ _ _-T -40°C to +125°C 5 SOT23-5
Open drain
MAX7376A_ _ _-T
-40°C to +125°C 5 SOT23-5
Active high
push-pull
MAX7376B_ _ _-T
-40°C to +125°C 5 SOT23-5
Active low
push-pull
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 twoletter code from Table 2 in the remaining two positions for the
desired frequency range. See Table 3 for standard part numbers.
Portable Equipment
Pin Configuration
Microcontroller (µC) Systems
TOP VIEW
CLOCK
1
5
E.C.
4
VCC
Typical Application Circuit appears at end of data sheet.
GND 2
MAX7376
RST/RST 3
SOT23
________________________________________________________________ Maxim Integrated Products
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.
1
MAX7376
General Description
The MAX7376 silicon oscillator with reset, is a replacement for ceramic resonators, crystals, crystal oscillator
modules, and discrete reset circuits. The MAX7376 provides 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 highimpedance 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 frequencies from 32.768kHz to 10MHz. See Table 2 for
standard frequencies and contact the factory for custom frequencies.
The MAX7376 is available in a 5-pin SOT23 package.
Refer to the MAX7382 data sheet for frequencies
≥10MHz. The MAX7376 standard operating temperature range is -40°C to +125°C. See the Applications
Information section for the extended operating temperature range.
MAX7376
Silicon Oscillator with Reset Output
ABSOLUTE MAXIMUM RATINGS
VCC to GND .............................................................-0.3V to +6V
All Other Pins to GND ................................-0.3V to (VCC + 0.3V)
CLOCK Current ................................................................±10mA
Continuous Power Dissipation (TA = +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
(VCC = 2.7V to 5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = 5V and TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Operating Supply Voltage
VCC
Operating Supply Current
ICC
CONDITIONS
MIN
TYP
2.7
MAX
UNITS
5.5
V
fCLOCK = 8MHz, no load
3
5
mA
fCLOCK = 32.768kHz, no load
13
25
µA
CLOCK OUTPUT
Minimum Operating Voltage
Output High Voltage
Output Low Voltage
Initial Frequency Accuracy
1.65
VCC = 2.7V, ISOURCE = 2.5mA
VCC
- 0.4
VOL
fCLOCK
VCC = 4.5V, ISINK = 20mA
0.4
VCC = 2.7V, ISINK = 10mA
0.4
VCC = 5V, TA = +25°C (Note 2)
-2
+2
VCC = 2.7V to 5.5V, TA = +25°C
-4
+4
(Note 3)
fCLOCK
Frequency Temperature
Sensitivity
VCC = 5V, TA = +25°C (Note 2)
32.440
VCC = 2.7V to 5.5V, TA = +25°C
31.785
32.768kHz (Note 3)
CLOCK Output Duty Cycle
43
Observation of 8MHz output for 20s using a
500MHz oscilloscope
CLOCK Output Jitter
V
V
VOH
Frequency Temperature
Sensitivity
Initial Frequency Accuracy
(32.768kHz)
VCC = 4.5V, ISOURCE = 9mA
VCC
- 0.4
±50
±325
32.768
33.096
33.751
V
%
ppm/oC
kHz
±50
±325
ppm/oC
50
57
%
160
psP-P
CLOCK Output Rise Time
tR
10% to 90%
5
ns
CLOCK Output Fall Time
tF
90% to 10%
5
ns
2
_______________________________________________________________________________________
Silicon Oscillator with Reset Output
MAX7376
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 2.7V to 5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = 5V and TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
TA = +25°C
VTH 2%
VTH +
2%
TA = -40°C to +125°C
VTH 5%
VTH +
5%
UNITS
RST/RST OUTPUT
Reset Threshold
VTH+
Reset Hysteresis
VTHYS
POR Delay
Output High Voltage
VOH
Output Low Voltage
VOL
Leakage Current
V
VCC rising
ILEAK
VHYST = {(VTH+) - ( VTH-)}/(VTH-) x 100%
2.0
%
VCC rising from 0V to (VTH + 200mV) in 1µs
100
µs
VCC = 4.5V, ISOURCE = 9mA
VCC - 0.4
VCC = 2.7V, ISOURCE = 2.5mA
VCC - 0.4
V
VCC = 4.5V, ISINK = 20mA
0.4
VCC = 2.7V, ISINK = 10mA
0.4
VCC = 5.5V, VRST = 5.5V, open drain
V
1
µA
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 Table 3.
Note 3: Guaranteed by design. Not production tested.
Typical Operating Characteristics
(VCC = 5V, TA = +25°C, unless otherwise noted.)
DUTY CYCLE
vs. SUPPLY VOLTAGE
51
CLOCK = 4MHz
50
53
DUTY CYCLE (%)
52
54
49
52
51
CLOCK = 4MHz
50
1.4
1.3
SUPPLY CURRENT (mA)
53
1.5
MAX7376 toc02
54
DUTY CYCLE (%)
55
MAX7376 toc01
55
SUPPLY CURRENT
vs. TEMPERATURE
49
1.2
1.1
1.0
48
47
47
0.7
46
46
0.6
45
45
-30
-5
20
45
70
TEMPERATURE (°C)
95
120
4.3
4.6
4.9
5.2
SUPPLY VOLTAGE (V)
5.5
CLOCK = 4MHz
0.9
48
-55
MAX7376 toc03
DUTY CYCLE
vs. TEMPERATURE
0.8
0.5
-55
-30
-5
20
45
70
95
120
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Typical Operating Characteristics (continued)
(VCC = 5V, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
FREQUENCY
vs. SUPPLY VOLTAGE
1.1
1.0
0.9
4.04
CLOCK = 4MHz
0.8
4.02
CLOCK = 4MHz
4.00
3.98
4.08
4.06
4.04
4.02
3.98
3.96
0.7
3.94
3.94
0.6
3.92
3.92
0.5
3.90
4.9
5.2
5.5
3.90
4.3
4.6
4.9
5.2
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
CLOCK OUTPUT WAVEFORM
(CL = 10pF)
CLOCK OUTPUT WAVEFORM
(CL = 50pF)
5.5
-55
-30
-5
20
45
70
95
120
TEMPERATURE (°C)
MAX7376 toc08
MAX7376 toc07
CLOCK OUTPUT WAVEFORM
(CL = 100pF)
MAX7376 toc09
4.6
CLOCK = 4MHz
4.00
3.96
4.3
MAX7376 toc06
4.06
FREQUENCY (MHz)
1.2
4.08
FREQUENCY (MHz)
1.3
4.10
MAX7376 toc05
1.4
FREQUENCY
vs. TEMPERATURE
4.10
MAX7376 toc04
1.5
SUPPLY CURRENT (mA)
CLOCK
CLOCK
CLOCK
f = 4MHz, CL = 10pF
f = 4MHz, CL = 50pF
f = 4MHz, CL = 100pF
40ns/div
40ns/div
40ns/div
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD
MAX7376 toc10
1000
MAXIMUM TRANSIENT DURATION (µs)
MAX7376
Silicon Oscillator with Reset Output
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
NAME
FUNCTION
1
CLOCK
2
GND
Push-Pull Clock Output
Ground
3
RST
Reset Output. See the RST Reset Output Options section for more details.
4
VCC
Positive Supply Voltage. Bypass VCC to GND with a 0.1µF capacitor.
5
E.C.
Must Be Externally Connected to VCC
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 standard frequencies are available (Table 2). No external
components are required for setting or adjusting the
frequency.
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 section for limit values of power-supply and pin voltages.
VCC
Oscillator
The clock output is a push-pull configuration and is
capable of driving a ground-connected 500Ω or a positive-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 position 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.
RST Reset Output Options
BIAS_V
RST/RST
POR
LOGIC
MUX
600kHz TO 10MHz
MAX7376
Figure 1. Functional Diagram
CLOCK
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 output. The RST output is asserted when the monitored
input (VCC) drops below the internal VTH- threshold and
remains asserted for 100µs after the monitored input
exceeds the internal VTH+ threshold. The open-drain
RST output requires an external pullup resistor.
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
MAX7376
Pin Description
MAX7376
Silicon Oscillator with Reset Output
The MAX7376 is relatively immune to vibration, shock,
and EMI influences, and thus provides a considerably
more robust clock source than crystal or ceramic resonator-based oscillator circuits.
Initial Power-Up and Operation
The clock starts up within 30µs (typ) after VCC has risen
above the reset threshold. The reset output remains
asserted for 100µs after the reset threshold is reached.
Extended Temperature Operation
The MAX7376 was tested to +135°C during product
characterization and shown to function normally at
this temperature (see the Typical Operating
Characteristics). However, production test and qualification is only performed from -40°C to +125°C at this
time. Contact the factory if operation outside this range
is required.
Power-Supply Considerations
The MAX7376 operates with a 2.7V and 5.5V powersupply voltage. Good power-supply decoupling is
needed to maintain the power-supply rejection performance of the MAX7376. Bypass VCC to GND with a
0.1µF surface-mount ceramic capacitor. Mount the
bypass capacitor as close to the device as possible. If
possible, mount the MAX7376 close to the µC’s decoupling capacitor so that additional decoupling is not
required. A larger value bypass capacitor is recommended if the MAX7376 is to operate with a large
capacitive load. Use a bypass capacitor value of at
least 1000 times that of the output load capacitance.
Typical Application Circuit
Table 1. Standard Reset Threshold Levels
SUFFIX
RESET THRESHOLD (V)
R
2.57
M
4.29
SUPPLY VOLTAGE
For all other reset threshold options, contact factory.
VCC
Table 2. Standard Frequencies
SUFFIX
STANDARD FREQUENCY (MHz)
AA
32.768kHz
MG
1
OK
1.8432
QT
3.39545
QW
3.6864
RD
4
RH
4.1943
TP
8
OSC1
CLOCK
E.C.
OSC2
MAX7376
RST
RST/RST
For all other reset threshold options, contact factory.
6
_______________________________________________________________________________________
µC
Silicon Oscillator with Reset Output
MAX7376
Table 3. Standard Part Numbers
PART
MAX7376CRAA
PIN-PACKAGE
RESET THRESHOLD
(V)
FREQUENCY
(Hz)
TOP MARK
5 SOT23
2.57
32.768k
AEUZ
MAX7376CRMG
5 SOT23
2.57
1M
AEUN
MAX7376CROK
5 SOT23
2.57
1.8432M
AEUJ
MAX7376CRQT
5 SOT23
2.57
3.39545M
AETT
MAX7376CRQW
5 SOT23
2.57
3.6864M
AETU
MAX7376CRRD
5 SOT23
2.57
4M
AETV
MAX7376CRRH
5 SOT23
2.57
4.1943M
AETW
MAX7376CRTP
5 SOT23
2.57
8M
AESF
AEUM
MAX7376CMMG
5 SOT23
4.29
1M
MAX7376CMOK
5 SOT23
4.29
1.8432M
AEUI
MAX7376CMQT
5 SOT23
4.29
3.39545M
AESH
MAX7376CMQW
5 SOT23
4.29
3.6864M
AETP
MAX7376CMRD
5 SOT23
4.29
4M
AESJ
MAX7376CMRH
5 SOT23
4.29
4.1943M
AETR
MAX7376CMTP
5 SOT23
4.29
8M
AETS
Chip Information
TRANSISTOR COUNT: 2027
PROCESS: BiCMOS
_______________________________________________________________________________________
7
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
SOT-23 5L .EPS
MAX7376
Silicon Oscillator with Reset Output
PACKAGE OUTLINE, SOT-23, 5L
21-0057
E
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.