MAX7377AXMG-T [MAXIM]
Analog Circuit, 1 Func, BICMOS, PDSO5, SOT-23, 5 PIN;
| 型号： | MAX7377AXMG-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Analog Circuit, 1 Func, BICMOS, PDSO5, SOT-23, 5 PIN 信息通信管理 光电二极管 |
| 文件： | 总9页 (文件大小：610K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3474; Rev 0; 10/04
Silicon Oscillator with Low-Power
Frequency Switching
General Description
Features
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.
♦ 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
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.
♦ 5ns Output Rise and Fall Time
♦ Low Jitter: 160ps
at 8MHz (No PLL)
(P-P)
♦ 3mA Fast-Mode Operating Current (8MHz)
♦ 13µA Slow-Mode Operating Current (32kHz)
♦ -40°C to +125°C Temperature Range
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.
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX7377AX_ _-T
-40°C to +125°C
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
Automotive
Consumer Products
Appliances and Controls
Handheld Products
Portable Equipment
Microcontroller Systems
Pin Configuration
TOP VIEW
CLOCK
GND
1
2
3
5
4
E.C.
MAX7377
SPEED
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
ABSOLUTE MAXIMUM RATINGS
CC
All Other Pins to GND ................................-0.3V to (V
CLOCK Current ................................................................ 10mA
V
to GND .............................................................-0.3V to +6V
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
+ 0.3V)
CC
Continuous Power Dissipation (T = +70°C)
A
5-Pin SOT23
(derate 7.1mW/°C above +70°C) ...................571mW (U5 - 2)
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
= 2.7V to 5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values are at V
= 5V and T = +25°C.) (Note 1)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
5.5
5
UNITS
V
Operating Supply Voltage
Operating Supply Current
LOGIC INPUT (SPEED)
Input High Voltage
V
2.7
CC
f
f
= 8MHz, no load
3
mA
µA
CLOCK
I
CC
= 32.768kHz, no load
13
25
CLOCK
0.7 x
V
V
IH
V
CC
0.3 x
Input Low Voltage
V
V
IL
V
CC
Input Current
I
2
µA
IN
CLOCK OUTPUT
V
- 0.4
CC
V
V
= 4.5V, I
= 2.7V, I
= 9mA
CC
CC
SOURCE
Output High Voltage
V
V
OH
V
- 0.4
CC
= 2.5mA
SOURCE
V
V
V
V
= 4.5V, I
= 2.7V, I
= 20mA
0.4
0.4
+2
+4
CC
CC
CC
CC
SINK
Output Low Voltage
V
V
OL
= 10mA
SINK
= 5V, T = +25°C (Note 2)
-2
-4
A
Initial Fast CLOCK Frequency
Accuracy
f
%
FCLOCK
= 2.7V to 5.5V, T = +25°C
A
2
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
ELECTRICAL CHARACTERISTICS (continued)
(V
= 2.7V to 5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values are at V
= 5V and T = +25°C.) (Note 1)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Fast CLOCK Frequency
Temperature Sensitivity
(Note 3)
50
325
ppm/oC
V
V
= 5V, T = +25°C (Note 2)
32.440 32.768 33.096
CC
CC
A
Initial Slow CLOCK Frequency
Accuracy
f
kHz
SCLOCK
= 2.7V to 5.5V, T = +25°C
31.785
33.751
A
Slow CLOCK Frequency
Temperature Sensitivity
(Note 3)
50
50
325
ppm/oC
%
CLOCK Output Duty Cycle
43
57
Observation of 8MHz output for 20s using a
500MHz oscilloscope
CLOCK Output Jitter
160
ps
P-P
CLOCK Output Rise Time
CLOCK Output Fall Time
Startup Delay
t
10% to 90%
90% to 10%
5
5
ns
R
t
ns
µs
F
V
rising from 0 to 5V in 1µs
100
2.2
CC
T
= +25°C
2.15
2.05
2.25
2.35
A
A
Output Undervoltage Lockout
UVLO
V
rising
V
CC
T
= -40°C to +125°C
Output Undervoltage Lockout
Hysteresis
V
45
mV
THYS
Note 1: All parameters are tested at T = +25°C. Specifications over temperature are guaranteed by design.
A
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
Typical Operating Characteristics
(V
= 5V, T = +25°C, unless otherwise noted.)
CC
A
DUTY CYCLE vs. SUPPLY VOLTAGE
DUTY CYCLE vs. TEMPERATURE
DUTY CYCLE vs. TEMPERATURE
55
54
53
52
51
50
49
48
47
46
45
55
54
53
52
51
50
49
48
47
46
45
55
54
53
52
51
50
49
48
47
46
45
CLOCK = 32kHz
CLOCK = 32kHz
CLOCK = 4MHz
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. TEMPERATURE
DUTY CYCLE vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
1.5
55
54
53
52
51
50
49
48
47
46
45
14.0
CLOCK = 4MHz
CLOCK = 4MHz
CLOCK = 32kHz
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
13.5
13.0
12.5
12.0
11.5
11.0
10.5
10.0
-55 -30 -5
20 45 70 95 120
4.3
4.6
4.9
5.2
5.5
-55 -30 -5
20 45 70 95 120
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
FREQUENCY vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
30
25
20
35.0
34.5
34.0
33.5
33.0
32.5
32.0
31.5
31.0
30.5
30.0
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
CLOCK = 32kHz
CLOCK = 32kHz
CLOCK = 4MHz
15
10
5
0
4.3
4.6
4.9
5.2
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
Typical Operating Characteristics (continued)
(V
= 5V, T = +25°C, unless otherwise noted.)
CC
A
FREQUENCY vs. SUPPLY VOLTAGE
FREQUENCY vs. TEMPERATURE
FREQUENCY vs. TEMPERATURE
4.10
4.08
4.06
4.04
4.02
4.00
3.98
3.96
3.94
3.92
3.90
33.0
32.9
32.8
32.7
32.6
32.5
32.4
32.3
32.2
32.1
32.0
4.10
4.08
4.06
4.04
4.02
4.00
3.98
3.96
3.94
3.92
3.90
CLOCK = 4MHz
CLOCK = 32kHz
CLOCK = 4MHz
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 = 10pF)
L
CLOCK OUTPUT WAVEFORM (C = 50pF)
L
CLOCK OUTPUT WAVEFORM (C = 100pF)
L
MAX7377 toc13
MAX7377 toc14
MAX7377 toc15
CLOCK
CLOCK
CLOCK
f = 4MHz, C = 50pF
L
f = 4MHz, C = 100pF
L
f = 4MHz, C = 10pF
L
40ns/div
40ns/div
40ns/div
HIGH-SPEED TO LOW-SPEED
TRANSITION
HIGH-SPEED TO LOW-SPEED
TRANSITION (EXPANDED SCALE)
MAX7377 toc16
MAX7377 toc17
20µs/div
400ns/div
_______________________________________________________________________________________
5
Silicon Oscillator with Low-Power
Frequency Switching
Typical Operating Characteristics (continued)
(V
= 5V, T = +25°C, unless otherwise noted.)
CC
A
LOW-SPEED TO HIGH-SPEED
TRANSITION
LOW-SPEED TO HIGH-SPEED
TRANSISTION (EXPANDED SCALE)
MAX7377 toc18
MAX7377 toc19
CLOCK
SPEED
20µs/div
400ns/div
Pin Description
PIN
1
NAME
CLOCK
GND
FUNCTION
Push-Pull Clock Output
Ground
2
Clock-Speed Select Input. Drive SPEED low to select the 32kHz fixed frequency. Drive SPEED high to
select factory-trimmed frequency.
3
SPEED
4
5
V
Positive Supply Voltage. Bypass V
to GND with a 0.1µF capacitor.
CC
CC
E.C.
Must be Externally Connected to V
CC
Oscillator
Detailed Description
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 when switching between high- and
low-speed modes. A typical startup characteristic is
shown in the Typical Operating Characteristics.
The MAX7377 is a dual-speed clock generator for
microcontrollers (µCs) and UARTs in 3V, 3.3V, and 5V
applications. (Figure 1). The MAX7377 is a replacement
for two crystal oscillator modules, crystals, or ceramic
resonators. The high-speed clock frequency is factory
trimmed to specific values. A variety of popular stan-
dard frequencies are available. The low-speed clock
frequency is fixed at 32.768kHz (Table 1). No external
components are required for setting or adjusting the
frequency.
Clock-Speed Select Input
The MAX7377 uses a logic input pin, SPEED, to set
clock speed. Take this pin low to select slow clock
speed (nominally 32.768kHz) or high to select full clock
Supply Voltage
The MAX7377 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.
speed. The SPEED input can be strapped to V
or to
CC
GND to select fast or slow clock speed, or connected
to a logic output (such as a processor port) used to
change clock speed on the fly. If the SPEED input is
connected to a processor port that powers up in the
6
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
Output Jitter
The MAX7377’s jitter performance is given in the
Electrical Characteristics table as a peak-to-peak value
obtained by observing the output of the MAX7377 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.
V
CC
MAX7377
600kHz TO 10MHz
(HF OSCILLATOR)
The jitter performance of clock sources degrades in the
POR
presence of mechanical and electrical interference.
The MAX7377 is relatively immune to vibration, shock,
and EMI influences, and thus provides a considerably
more robust clock source than crystal or ceramic res-
SPEED
MUX
onator-based oscillator circuits.
CLOCK
LOGIC
Initial Power-Up and Operation
An internal power-up reset disables the oscillator until
has risen above 2.2V. The clock then starts up
within 30µs (typ) at the frequency determined by the
SPEED pin.
V
CC
32kHz
(LF OSCILLATOR)
Extended Temperature Operation
The MAX7377 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 qualifi-
cation is only performed from -40°C to +125°C at this
time. Contact the factory if operation outside this range
is required.
Figure 1. Functional Diagram
input condition, connect a pullup or pulldown resistor to
the SPEED input to set the clock to the preferred speed
on power-up. The leakage current through the resistor
into the SPEED input is very low, so a resistor value as
high as 500kΩ may be used.
Power-Supply Considerations
The MAX7377 operates with a 2.7V and 5.5V power-
supply voltage. Good power-supply decoupling is
needed to maintain the power-supply rejection perfor-
mance of the MAX7377. Bypass V
to GND with a
Applications Information
Interfacing to a Microcontroller
Clock Input
CC
0.1µF surface-mount ceramic capacitor. Mount the
bypass capacitor as close to the device as possible. If
possible, mount the MAX7377 close to the microcon-
troller’s decoupling capacitor so that additional decou-
pling is not required. A larger value bypass capacitor is
recommended if the MAX7377 is to operate with a large
capacitive load. Use a bypass capacitor value of at
least 1000 times that of the output load capacitance.
The MAX7377 clock output is a push-pull, CMOS, logic
output that directly drives any microprocessor (µP) or
µC clock input. There are no impedance-matching
issues when using the MAX7377. The MAX7377 is not
sensitive to its position on the board and does not need
to be placed right next to the µP. Refer to the microcon-
troller data sheet for clock-input compatibility with exter-
nal clock signals. The MAX7377 requires no biasing
components or load capacitance. When using the
MAX7377 to retrofit a crystal oscillator, remove all bias-
ing components from the oscillator input.
_______________________________________________________________________________________
7
Silicon Oscillator with Low-Power
Frequency Switching
Typical Application Circuit
Table 1. Standard Frequencies
SUFFIX
MG
OK
STANDARD FREQUENCY (MHz)
SUPPLY VOLTAGE
1
1.8432
3.39545
3.6864
4
QT
QW
RD
OSC1
OSC2
V
CC
RH
4.1943
8
CLOCK
SPEED
TP
E.C.
For all other reset threshold options, contact factory.
µC
MAX7377
I/O PORT
Table 2. Standard Part Numbers
FREQUENCY
TOP MARK
(Hz)
PART
PIN-PACKAGE
MAX7377AXMG
5 SOT23
5 SOT23
5 SOT23
5 SOT23
5 SOT23
5 SOT23
5 SOT23
1M
1.8432M
3.39545M
3.6864M
4M
AENE
AEND
AEMY
AEMZ
AENA
AENB
AENC
MAX7377AXOK
MAX7377AXQT
MAX7377AXQW
MAX7377AXRD
MAX7377AXRH
MAX7377AXTP
4.1943M
8M
Chip Information
TRANSISTOR COUNT: 2027
PROCESS: BiCMOS
8
_______________________________________________________________________________________
Silicon Oscillator with Low-Power
Frequency Switching
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.)
PACKAGE OUTLINE, SOT-23, 5L
1
21-0057
E
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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