MAXIM MAX7384A

19-3493; Rev 0; 11/04
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
Applications
White Goods
Features
♦ 2.7V to 5.5V Operation
♦ High-Speed Oscillator from 10MHz to 16MHz
Low-Speed 32kHz Oscillator
Glitch-Free Clock-Speed Switching
♦ Integrated POR
♦ ±10mA Clock-Output Drive Capability
♦ 2.5% Initial Accuracy
♦ ±50ppm/°C Frequency Drift
♦ 50% Duty Cycle
♦ 5ns Output Rise and Fall Time
♦ Low Jitter: 80psP-P at 16MHz
♦ 4mA Operating Current at 16MHz
♦ 13µA, 32kHz Operating Current
♦ -40°C to +125°C Temperature Range
Ordering Information
PART*
TEMP RANGE
PINPACKAGE
RESET
OUTPUT
MAX7384A_ _ _
-40°C to +125°C 8 µMAX
Active high
push-pull
MAX7384B_ _ _
-40°C to +125°C 8 µMAX
Active low
push-pull
MAX7384C_ _ _
-40°C to +125°C 8 µMAX
Open drain
*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.
Table 1 and Table 2 are located at the end of the data sheet.
Automotive
Consumer Products
Typical Application Circuit
Appliances and Controls
VCC 2.7V TO 5.5V
Handheld Products
Portable Equipment
0.1µF
0.1µF
Microcontroller Systems
VCC
VL
CLOCK
OSC1
OSC2
MAX7384
E.C.
RST/RST
RST
µC
I/O PORT
µMAX is a registered trademark of Maxim Integrated Products, Inc.
SPEED
GND
Pin Configuration appears at end of data sheet.
________________________________________________________________ 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
MAX7384
General Description
The MAX7384 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
MAX7384 features a factory-programmed high-speed
oscillator, a 32.768kHz oscillator, a clock-selector input,
and a µP power-on-reset (POR) supervisor. The clock
output can be switched at any time between the highspeed 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 MAX7384 is resistant to vibration and EMI.
The high-output-drive current and absence of highimpedance nodes makes the oscillator less susceptible
to dirty or humid operating conditions. With a wide operating temperature range as standard, the MAX7384 is a
good choice for demanding home appliance, industrial,
and automotive environments.
The MAX7384 is available with factory-programmed frequencies ranging from 10MHz to 16MHz. See Table 1
for standard frequencies and contact the factory for
custom frequencies. Refer to the MAX7378 data sheet
for frequencies less than 10MHz.
The MAX7384 is available in an 8-pin µMAX® package.
The MAX7384 standard operating temperature range is
-40°C to +125°C. See the Applications Information section for extended operating temperature range.
MAX7384
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +6.0V
All Other Pins to GND.................................-0.3V to (VCC + 0.3V)
CLOCK, RST Current .......................................................±50mA
Input Current (SPEED)......................................................±50mA
Continuous Power Dissipation (TA = +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) ...362mW (U8-1)
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, VCC = 2.7V to 5.5V, VL = VCC, TA = -40°C to +125°C. Typical values are at VCC = 5.0V, TA = +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Operating Supply Voltage
Operating Supply Current
SYMBOL
CONDITIONS
VCC
ICC
MIN
TYP
2.7
MAX
UNITS
5.5
V
fCLOCK = 16MHz, TA = -40°C to +125°C, no
load
8.7
fCLOCK = 14.7456MHz, TA = -40°C to
+125°C, no load
8.0
fCLOCK = 12MHz, TA = -40°C to +125°C, no
load
6.5
fCLOCK = 11.0592MHz, TA = -40°C to
+125°C, no load
6.0
fCLOCK = 10MHz, TA = -40°C to +125°C, no
load
5.4
fCLOCK = 32.768kHz, TA = -40°C to
+125°C, no load
13
25
mA
µA
LOGIC INPUTS (SPEED)
Input High Voltage
VIH
Input Low Voltage
VIL
Input Current
IIN
0.7 x VCC
V
0.3 x VCC
VCC = SPEED = 5.5V
2
µA
CLOCK OUTPUT
Output High Voltage
VOH
Output Low Voltage
VOL
Initial Fast Clock Frequency
Accuracy
Fast Clock Temperature
Coefficient
2
fCLOCK
VL = 4.5V, ISOURCE = 7.0mA
VL = 2.7V, ISOURCE = 2.0mA
VL - 0.4
V
VL = 4.5V, ISINK = 20mA
0.4
VL = 2.7V, ISINK = 10mA
VCC = 5V, TA = +25°C, deviation from
selected frequency
-2.5
+2.5
VCC = 2.7V to 5.5V, TA = +25°C,
deviation from selected frequency
-5
+3.5
V
%
TA = -40°C to +125°C
±50
_______________________________________________________________________________________
±350
ppm/°C
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
(Typical Operating Circuit, VCC = 2.7V to 5.5V, VL = VCC, TA = -40°C to +125°C. Typical values are at VCC = 5.0V, TA = +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Slow Clock Frequency
SYMBOL
fCLOCK
MIN
TYP
MAX
VCC = 5V, TA = +25°C
CONDITIONS
32.268
32.768
33.268
UNITS
VCC = 2.7V to 5.5V, TA = +25°C
31.768
32.768
33.768
±50
±325
ppm/°C
50
60
%
kHz
Slow Clock Temperature
Coefficient
TA = -40°C to +125°C
Duty Cycle
(Note 2)
Output Jitter
Observation of 16MHz for 20s using a
12GHz oscilloscope
80
psP-P
5
ns
Output Rise Time
tR
10% to 90%
Output Fall Time
tF
90% to 10%
Power-On-Reset Threshold
VTH
Power-On-Reset Hysteresis
VHYST
Power-On-Reset Delay
PORdly
VCC rising, deviation
from nominal threshold
40
5
ns
TA = +25°C
-2
+2
TA = -40°C to
+125°C
-5
+5
Difference between rising and falling
thresholds
VCC rising from 0 to 5V in 1µs at +25°C
%
1
%
122
µs
RESET OUTPUT
Output High Voltage
(Note 3)
Output Low Voltage
VL = 4.5V, ISOURCE = 7.0mA
VCC 0.4
VL = 2.7V, ISOURCE = 2.0mA
VCC 0.4
V
VOH
VOL
VL = 4.5V, ISINK = 20mA
0.4
VL = 2.7V, ISOURCE = 10mA
0.4
V
Note 1: All parameters tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 2: Guaranteed by design. Not production tested.
Note 3: For push-pull output only.
_______________________________________________________________________________________
3
MAX7384
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VCC = VL = 5V, TA = +25°C, frequency = 10MHz, unless otherwise noted.)
DUTY CYCLE vs. SUPPLY VOLTAGE
50
48.5
49
48
47
46
-17
21
59
97
3.1
TEMPERATURE (°C)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
FREQUENCY = 11.0592MHz
3.5
3.5
3.9
4.3
4.7
5.1
-55
2.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
59
FREQUENCY DEVIATION
vs. TEMPERATURE
FREQUENCY = 11.0592MHz
4
FREQUENCY = 10MHz
3
PERCENT (%)
0.5
0
-0.5
1
0
-1
-1.0
-2
-1.5
-3
-4
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-55
-17
21
59
SETTLING TIME FROM START
CLOCK OUTPUT WAVEFORM
(CL = 10pF)
MAX7384 toc08
CLOCK OUTPUT WAVEFORM
(CL = 50pF)
135
MAX7384 toc09
CH1 FREQ
9.992MHz
LOW RESOLUTION
20ns/div
97
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
MAX7384 toc07
20ns/div
CHANNEL 1 = CLOCK, CHANNEL 2 = VCC
4
135
2
SUPPLY VOLTAGE (V)
10µs/div
97
FREQUENCY DEVIATION
vs. SUPPLY VOLTAGE
-2.0
1.5
21
TEMPERATURE (°C)
1.5
PERCENT (%)
2.5
-17
SUPPLY VOLTAGE (V)
1.0
3.0
3.00
5.5
2.0
MAX7384 toc04
4.0
FREQUENCY = 10MHz
3.05
2.90
2.7
135
MAX7384 toc05
-55
3.10
2.95
45
48.0
3.15
MAX7384 toc06
49.0
3.20
SUPPLY CURRENT (mA)
FREQUENCY = 10MHz
3.25
MAX7384 toc02
MAX7384 toc01
49.5
FREQUENCY = 11.0592MHz
DUTY CYCLE (%)
DUTY CYCLE (%)
50.0
SUPPLY CURRENT vs. TEMPERATURE
51
MAX7384 toc03
DUTY CYCLE vs. TEMPERATURE
50.5
SUPPLY CURRENT (mA)
MAX7384
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
_______________________________________________________________________________________
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
CLOCK OUTPUT WAVEFORM
(CL = 100pF)
HIGH-SPEED TO LOW-SPEED
TRANSITION
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX7384 toc10
MAX7384 toc12
MAX7384 toc11
MAXIMUM TRANSIENT DURATION (s)
1
0.1
0.01
1m
10m
VRESET = 4.32V
100m
1µ
0.04
20ns/div
0.14
0.09
0.19
10µs/div
0.24
RESET THRESHOLD OVERDRIVE (V)
HIGH-SPEED TO LOW-SPEED
TRANSITION
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
LOW-SPEED TO HIGH-SPEED
TRANSITION
LOW-SPEED TO HIGH-SPEED
TRANSITION
MAX7384 toc13
MAX7384 toc15
MAX7384 toc14
40ns/div
100ns/div
10µs/div
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
SUPPLY CURRENT vs. FREQUENCY
SUPPLY CURRENT (mA)
MAX7384 toc16
5
4
3
2
1
10
11
12
13
14
15
16
FREQUENCY (MHz)
_______________________________________________________________________________________
5
MAX7384
Typical Operating Characteristics (continued)
(VCC = VL = 5V, TA = +25°C, frequency = 10MHz, unless otherwise noted.)
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
MAX7384
Pin Description
PIN
NAME
1
VCC
FUNCTION
2
VL
3
SPEED
4
RST
5
CLOCK
6
GND
Ground
7
E.C.
Externally Connected. Connect to Vcc.
8
N.C.
No Connection. Not internally connected.
Positive Supply Voltage. Bypass VCC to GND with a 0.1µF capacitor.
Output Supply Voltage. Bypass VL to GND with a 0.1µF capacitor. VL must be connected to VCC.
Clock-Speed Select Input. Drive SPEED low to select the 32kHz fixed frequency. Drive SPEED high
to select factory-trimmed frequency.
Reset Output. Open-drain or push-pull output. See the Ordering Information.
Push-Pull Clock Output
Detailed Description
The MAX7384 is a dual-speed clock generator with integrated reset for microcontrollers (µCs) and UARTs in 3V,
3.3V, and 5V applications. The MAX7384 is a replacement for crystal-oscillator modules, crystals, or ceramic
resonators and a system reset IC. The high-speed clock
frequency and reset threshold voltage are factory
trimmed to specific values (see Table 1). A variety of
popular standard frequencies are available. The lowspeed clock frequency is fixed at 32.768kHz; see Table
2. No external components are required for setting or
adjusting the frequency.
Oscillator
The push-pull clock output drives a 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 changing of the frequency. A typical oscillating startup is shown in the Typical Operating Characteristics.
VCC 2.7V TO 5.5V
VL
Clock-Speed Selection
Drive SPEED low to select slow clock speed (nominally
32.768kHz) or high to select full clock speed. SPEED can
be connected to VCC or to GND to select fast or slow
clock speed, or connected to a logic output (such as a µP
GPIO port) used to change clock speed on the fly. If
SPEED is connected to a µP GPIO port, connect a pullup
or pulldown resistor to set the clock to the preferred
speed on power-up. SPEED input bias current is 2µA
(max), so a resistor value as high as 500kΩ can be used.
Applications Information
Interfacing to a Microcontroller
Clock Input
The MAX7384 clock output is a push-pull, CMOS, logic
output that directly drives a µP or µC clock input. There
are no impedance-matching issues when using the
MAX7384. Refer to the microcontroller data sheet for
clock input compatibility with external clock signals.
The MAX7384 requires no biasing components or load
capacitance. When using the MAX7384 to retrofit a
crystal oscillator, remove all biasing components from
the oscillator input.
Reset Output
POR
MAX7384
RST
32kHz
(LF OSCILLATOR)
SPEED
LOGIC
MUX
10MHz TO 16MHz
(HF OSCILLATOR)
GND
CLOCK
The MAX7384 is available with three reset output stage
options: push-pull active low, push-pull active high, and
open-drain active low. RST is asserted when the monitored input (VCC) drops below the internal VTH- threshold
and remains asserted for 120µs after the monitored input
exceeds the internal VTH+ threshold. The open-drain
RST output requires an external pullup resistor.
Output Jitter
The MAX7384’s jitter performance is given in the
Electrical Characteristics table as a peak-to-peak value
obtained by observing the output of the MAX7384 for
Figure 1. Functional Diagram
6
_______________________________________________________________________________________
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
Initial Power-Up and Operation
An internal power-up reset asserts RST until the supply
voltage has risen above the power-on-reset threshold
(VTH+).
RST holds the microcontroller in a reset condition until
120µs after VCC has risen above VTH+. This reset delay
ensures that the clock output and the microcontroller’s
internal clock circuits have stabilized before the system
is allowed to start. Typical microcontroller reset delay
ranges from 1ms to 250ms to allow a slow crystal oscillator circuit to start up. The MAX7384 has a fast startup,
eliminating the need for such a long reset delay.
Extended Temperature Operation
The MAX7384 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 MAX7384 operates with a 2.7V and 5.5V powersupply voltage. VCC provides power to the the internal
circuitry and VL supplies power to the clock and reset
outputs. Good power-supply decoupling is needed to
maintain the power-supply rejection performance of the
MAX7384. Bypass both V CC and V L to GND with a
0.1µF surface-mount ceramic capacitor. Mount the
bypassing capacitors as close to the device as possible. Use a larger value bypass capacitor if the MAX7384
is to operate with a large capacitive load. Use a bypass
capacitor value of at least 1000 times that of the output
load capacitance.
MAX7384
20s with a 12GHz oscilloscope. Jitter measurements
are approximately proportional to the output period of
the device. Thus, a 10MHz device has approximately
twice the jitter value of a 20MHz device. The jitter performance of all clock sources degrades in the presence of mechanical and electrical interference. The
MAX7384 is relatively immune to vibration, shock, and
EMI influences and thus provides a considerably more
robust clock source than crystal or ceramic resonatorbased oscillator circuits.
Table 1. Standard Reset Threshold
Levels
SUFFIX
X
V
R
Q
P
N
J
M
RESET THRESHOLD (V)
2.50
2.71
2.89
Standard value
3.13
3.34
3.44
3.96
4.38
Standard value
Contact factory for nonstandard reset threshold options.
Table 2. Standard Frequencies
SUFFIX
STANDARD FREQUENCY (MHz)
UK
10
UT
11.0592
VB
12
VT
14.7456
WB
16
For all other frequency options, contact factory.
Table 3. Standard Part Numbers
PART
RESET
OUTPUT
TYPE
RESET
FREQUENCY
THRESHOLD
(MHz)
(V)
MAX7384CRUK
Open drain
2.89
10
MAX7384CRUT
Open drain
2.89
11.0592
MAX7384CRVB
Open drain
2.89
12
MAX7384CRVT
Open drain
2.89
14.7456
MAX7384CRWB Open drain
2.89
16
MAX7384CMUK Open drain
4.38
10
MAX7384CMUT
Open drain
4.38
11.0592
MAX7384CMVB
Open drain
4.38
12
MAX7384CMVT
Open drain
4.38
14.7456
MAX7384CMWB Open drain
4.38
16
_______________________________________________________________________________________
7
MAX7384
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
Pin Configuration
Chip Information
TRANSISTOR COUNT: 2937
PROCESS: BiCMOS
TOP VIEW
VCC 1
8
N.C.
7
E.C.
3
6
GND
RST 4
5
CLOCK
VL 2
SPEED
MAX7384
µMAX
8
_______________________________________________________________________________________
Silicon Oscillator with Low-Power Frequency
Switching and Reset Output
E
ÿ 0.50±0.1
8
INCHES
DIM
A
A1
A2
b
H
c
D
e
E
H
0.6±0.1
1
L
1
α
0.6±0.1
S
BOTTOM VIEW
D
MIN
0.002
0.030
MAX
0.043
0.006
0.037
0.014
0.010
0.007
0.005
0.120
0.116
0.0256 BSC
0.120
0.116
0.198
0.188
0.026
0.016
6∞
0∞
0.0207 BSC
8LUMAXD.EPS
4X S
8
MILLIMETERS
MAX
MIN
0.05
0.75
1.10
0.15
0.95
0.25
0.36
0.13
0.18
2.95
3.05
0.65 BSC
2.95
3.05
4.78
5.03
0.41
0.66
0∞
6∞
0.5250 BSC
TOP VIEW
A1
A2
e
A
c
b
α
L
SIDE VIEW
FRONT VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
APPROVAL
DOCUMENT CONTROL NO.
21-0036
REV.
J
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.
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.
MAX7384
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.)