MAX7390srff [MAXIM]
Microcontroller Clock Generator with Watchdog; 微控制器时钟发生器，带有看门狗
| 型号： | MAX7390srff |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Microcontroller Clock Generator with Watchdog |
| 文件： | 总11页 (文件大小：295K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3897; Rev 1; 2/06
Microcontroller Clock Generator with
Watchdog
General Description
The MAX7389/MAX7390 replace ceramic resonators,
crystals, and supervisory functions for microcontrollers
in 3.3V and 5V applications.
Features
♦ Robust Microcontroller Clock and Supervisor in a
Single Package
♦ Integrated Reset and Watchdog Functions
♦ Pin-Programmable Watchdog Timeout
♦ Speed Select
The MAX7389/MAX7390 provide a clock source, reset,
and watchdog functions. The watchdog timer is pin pro-
grammable and provides watchdog timeout values in
the 16ms to 2048ms range. The MAX7389 provides a
separate watchdog output that is used as a status indi-
cator or to control safety-critical system elements.
♦ +2.7V to +5.5V Operation
♦ Factory-Trimmed Oscillator
♦ Reset Valid Down to 1.1V Supply Voltage
♦ ±1ꢀmꢁ Clock-Output Drive Current
♦ ±±4 Total ꢁccuracy ꢂor -±ꢀ0C to +1250C
♦ ±2.754 Total ꢁccuracy ꢂor ꢀ0C to +ꢃ50C
♦ 5.5mꢁ Operating Current (12MHz Version)
♦ -±ꢀ0C to +1250C Temperature Range
♦ ꢃ-Pin µMꢁX Surꢂace-Mount Package
♦ 1MHz to 16MHz Factory Preset Frequency
The MAX7390 features a clock-speed select that
reduces the output frequency by half. This functionality
allows the microcontroller to operate at reduced power
and may be used to extend the time available to per-
form housekeeping tasks, such as writing data to flash
during a power failure.
The MAX7389/MAX7390 clock outputs are factory pro-
grammed to a frequency in the 1MHz to 16MHz range.
Four standard frequencies are available. Other frequen-
cies are available upon request. The maximum operating
supply current is 5.5mA with a clock frequency of 12MHz.
Ordering Information
Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7389/MAX7390 are resistant to EMI
and vibration, and operate reliably at high tempera-
tures. The high-output drive current and absence of
high-impedance nodes make the oscillator invulnerable
to dirty or humid operating conditions.
PIN-
PꢁCKꢁGE
PKG
CODE
PꢁRT
TEMP RꢁNGE
MꢁX73ꢃ9srff
MꢁX739ꢀsrff
-40oC to +125oC
-40oC to +125oC
8 µMAX
8 µMAX
U8-1
U8-1
The MAX7389/MAX7390 are available in an 8-pin µMAX®
package. The MAX7389/MAX7390 standard operating
temperature range is from -40°C to +125°C.
Note: “s” is a placeholder for the reset output type. Insert the
symbol found in Table 3 in the place of “s.” “r” is a placeholder
for the power-on reset (POR) voltage. Insert the symbol found in
Table 2 in the place of “r.” “ff” is a placeholder for the nominal
output frequency. Insert the symbol found in Table 4 in the
place of “ff.” For example, MAX7389CMTP describes a device
with 4.38V reset level, open-collector RST output, and a clock
output frequency of 8MHz.
Applications
White Goods
Automotive
Handheld Products
Portable Equipment
Typical Application Circuit, Functional Diagram, and Selector
Guide appear at end of data sheet.
Appliances and Controls Microcontroller Systems
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations
TOP VIEW
TOP VIEW
V
1
2
3
4
8
7
6
5
CLOCK
CC
V
1
2
3
4
8
7
6
5
CLOCK
RST/RST
WDI
CC
RST/RST
WDS1
WDS2
GND
WDS1
WDS2
GND
MAX7389
MAX7390
WDI
WDO
SPEED
µMꢁX
µMꢁX
________________________________________________________________ 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.
Microcontroller Clock Generator with
Watchdog
ꢁBSOLUTE MꢁXIMUM RꢁTINGS
CC
All Other Pins to GND ................................-0.3V to (V
CLOCK, RST/RST, WDO Output Current ......................... 50mA
V
to GND...........................................................-0.3V to +6.0V
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
+ 0.3V)
CC
Continuous Power Dissipation (T = +70°C)
A
8-Pin µMAX (derate 4.5mW/°C over +70°C)................362mW
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.
ELECTRICꢁL CHꢁRꢁCTERISTICS
(Typical Application Circuit, V
= +2.7V to +5.5V, T = -40°C to +125°C, 1MHz to 16MHz output frequency range, typical values at
CC
A
V
CC
= +5.0V, T = +25°C, unless otherwise noted.) (Note 1)
A
PꢁRꢁMETER
SYMBOL
CONDITIONS
MIN
TYP
MꢁX
UNITS
POWER REQUIREMENTS
Operating Supply Voltage
V
2.7
5.5
1.1
V
V
CC
T
T
= 0°C to +85°C
A
Valid RST/RST Supply Voltage
V
CCR
= -40°C to +125°C
1.18
5.5
A
f
= 12MHz
= 8MHz
CLOCK
CLOCK
Operating Supply Current
I
mA
CC
f
4.5
TRI-LEVEL ꢁNꢁLOG INPUTS: WDS1, WDS2
Input-High Voltage Level
V
- 0.55V
V
V
V
CC
Input-Middle Voltage Level
Input-Low Voltage Level
0.9
V
- 1.1V
0.45
CC
LOGIC INPUT: WDI
Input Leakage Current
Logic-Input High Voltage
Logic-Input Low Voltage
I
Input high
0.5
µA
V
LEAK
V
0.7 x V
CC
IH
V
0.3 x V
V
IL
CC
PUSH-PULL LOGIC OUTPUTS: RST/RST
Output High
Output Low
V
I
I
= 1mA
V
- 1.5
V
V
OH
SOURCE
CC
V
= 3mA
SINK
0.05
0.05
0.4
OL
OPEN-DRꢁIN LOGIC OUTPUTS: RST, PFO, WDO
Output Low
V
I
= 3mA
0.4
V
OLO
SINK
OUTPUT: CLOCK
Output High Voltage
Output Low Voltage
V
I
I
= 5mA
V
- 0.3
V
V
OHC
SOURCE
CC
V
= 5mA
SINK
0.3
+2.75
+4
OLC
T
T
= 0°C to +85°C, V
= 5.0V
CC
-2.75
-4
A
A
CLOCK Accuracy
f
%
CLOCK
= -40°C to +125°C, V
= 5.0V
CC
Clock Frequency Temperature
Coefficient
V
= 5.0V (Note 2)
140
400
1
ppm/°C
%/V
CC
Clock Frequency Supply Voltage
Coefficient
T
A
= +25°C (Note 2)
0.67
2
_______________________________________________________________________________________
Microcontroller Clock Generator with
Watchdog
ELECTRICꢁL CHꢁRꢁCTERISTICS (continued)
(Typical Application Circuit, V
= +2.7V to +5.5V, T = -40°C to +125°C, 1MHz to 16MHz output frequency range, typical values at
CC
A
V
CC
= +5.0V, T = +25°C, unless otherwise noted.) (Note 1)
A
PꢁRꢁMETER
SYMBOL
CONDITIONS
MIN
TYP
MꢁX
UNITS
CLOCK Duty Cycle
(Note 2)
45
50
55
%
Observation for 20s using a 500MHz
oscilloscope
ps
CLOCK Output Jitter
310
RMS
Output Rise Time
t
C
C
= 10pF, 10% to 90% of full scale (Note 2)
= 10pF, 90% to 10% of full scale (Note 2)
2.5
2.8
7.0
7.5
ns
ns
R
LOAD
LOAD
Output Fall Time
t
F
INTERNꢁL POWER-ON RESET
V
V
TH
+ 1.5%
TH
T
T
= +25°C
A
- 1.5%
V
V
V
rising, Table 2
TH+
CC
CC
V
V
TH
+ 2.5%
TH
Reset Voltage
= -40°C to +125°C
V
A
- 2.5%
0.98 x
V
falling
TH-
V
TH+
Reset Timeout Period
t
Figures 1, 2
86
135
250
µs
RST
WꢁTCHDOG
WDS1 = GND, WDS2 = GND
WDS1 = open, WDS2 = GND
11
22
16
32
22
44
WDS1 = V , WDS2 = GND
CC
44
64
88
WDS1 = GND, WDS2 = open
WDS1 = open, WDS2 = open
88
128
256
512
1024
2048
177
354
708
1416
2832
Watchdog Timeout Period
(Figure 2)
ms
t
177
354
708
1416
WDG
WDS1 = V , WDS2 = open
CC
WDS1 = GND, WDS2 = V
WDS1 = open, WDS2 = V
CC
CC
WDS1 = WDS2 = V (watchdog disabled)
CC
POWER FꢁIL
0.65 x
0.85 x
V
CC
Power-Fail Select Threshold
V
PFI input
V
V
SEL
V
CC
V
Monitoring Threshold
CC
V
V
V
rising
falling
4.06
1.0
0.9
1.0
4.38
2
4.60
4.0
1.4
8.0
ITH
CC
CC
(Internal Threshold)
Internal Threshold Hysteresis
V
%V
ITH
IHYST
PFI Monitoring Threshold
(External Threshold)
External Threshold Hysteresis
V
PFI rising
PFI falling
1.1
3.5
V
ETH
V
%V
ETH
EHYST
Note 1: All parameters are tested at T = +25°C. Specifications over temperature are guaranteed by design.
A
Note 2: Guaranteed by design. Not production tested.
_______________________________________________________________________________________
3
Microcontroller Clock Generator with
Watchdog
Typical Operating Characteristics
(Typical Application Circuit, V
= +5V, f
= 16MHz, T = +25°C, unless otherwise noted.)
CC
CLOCK
A
FREQUENCY vs. SUPPLY VOLTAGE
FREQUENCY vs. TEMPERATURE
DUTY CYCLE vs. SUPPLY VOLTAGE
1.020
1.010
1.000
0.990
0.980
1.040
1.030
1.020
1.010
1.000
0.990
0.980
52
51
50
49
48
NORMALIZED TO V = +5V
CC
V
= +2.9V
TH+
NORMALIZED TO T = +25°C
V
= +2.9V
A
TH+
2.90
3.55
4.20
(V)
4.85
5.50
-40 -25 -10
5
20 35 50 65 80 95 110 125
2.90
3.55
4.20
(V)
4.85
5.50
V
TEMPERATURE (°C)
CC
V
CC
CLOCK OUTPUT WAVEFORM
CLOCK OUTPUT WAVEFORM
WITH C = 10pF
WITH C = 50pF
DUTY CYCLE vs. TEMPERATURE
L
L
MAX7389 toc05
MAX7389 toc06
52
51
50
49
48
V
= +3.3V
V
= +3.3V
CC
CC
CLOCK
1V/div
CLOCK
1V/div
40ns/div
40ns/div
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
CLOCK OUTPUT WAVEFORM
WITH C = 100pF
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
L
MAX7389 toc07
5
4
3
2
1
5
4
3
2
1
V
= +5V
CC
CLOCK
1V/div
V
= +3.3V
CC
V
= +2.9V
TH+
40ns/div
-40 -25 -10
5
20 35 50 65 80 95 110 125
2.90
3.55
4.20
(V)
4.85
5.50
TEMPERATURE (°C)
V
CC
±
_______________________________________________________________________________________
Microcontroller Clock Generator with
Watchdog
Typical Operating Characteristics (continued)
(Typical Application Circuit, V
= +5V, f
= 16MHz, T = +25°C, unless otherwise noted.)
CC
CLOCK A
CLOCK SETTLING TIME FROM START
POWER-ON RESET BEHAVIOR
MAX7389 toc10
MAX7389/90 toc11
V
CC
V
2V/div
CC
2V/div
CLOCK
5V/div
CLOCK
2V/div
RST
5V/div
t
RST
1µs/div
100µs/div
MAXIMUM V TRANSIENT DURATION
CC
vs. RESET THRESHOLD OVERDRIVE
RESPONSE OF RST AND WDO
WDI EXCEEDING t
WDG
MAX7389/90 toc13
1000
100
10
WDI
2V/div
RESET OCCURS ABOVE THIS CURVE
WDO
5V/div
t
WDG
RST
5V/div
t
RST
V
FALLING FROM V + 100mV
TH+
CC
1
100 200 300 400 500 600 700 800 900 1000
RESET THRESHOLD OVERDRIVE (mV)
2ms/div
RISING THRESHOLD vs. TEMPERATURE
CLOCK RESPONSE TO SPEED SELECT INPUT
MAX7389/90 toc15
2.90
2.88
2.86
2.84
2.82
2.80
SPEED
2V/div
CLOCK
2V/div
-40 -25 -10
5
20 35 50 65 80 95 110 125
200ns/div
TEMPERATURE (°C)
_______________________________________________________________________________________
5
Microcontroller Clock Generator with
Watchdog
Pin Description
PIN
NꢁME
FUNCTION
MꢁX73ꢃ9
MꢁX739ꢀ
Power Input. Connect V
Install the bypass capacitor as close to the device as possible.
to the power supply. Bypass V
to GND with a 1µF capacitor.
CC
CC
1
1
V
CC
Watchdog Timeout Select Input 1. Connect WDS1 and WDS2 to V , GND, or V /2, as
shown in Table 1, to set the watchdog timeout period.
CC
CC
2
2
WDS1
Watchdog Timeout Select Input 2. Connect WDS2 and WDS1 to V , GND, or V /2, as
shown in Table 1, to set the watchdog timeout period.
Ground
CC
CC
3
4
5
3
4
WDS2
GND
Watchdog Output. Open-drain watchdog output asserts if WDI is not toggled within the
watchdog timeout period.
⎯
WDO
Clock-Speed Select Input. Connect SPEED high for the factory-trimmed clock output
frequency. Connect SPEED low to reduce the clock output frequency by half.
—
6
5
6
SPEED
WDI
Watchdog Input. A rising edge on WDI resets watchdog timer. If WDI does not receive a
rising edge within the watchdog timeout period (t
), RST/RST asserts. The watchdog
WDG
timeout period is programmable through WDS1 and WDS2. Connect WDS1 and WDS2 to
to disable the watchdog timer.
V
CC
Reset Output. Reset output is available in one of three configurations: push-pull RST, push-
pull RST, or open-drain RST. The reset output is asserted if one of the following conditions
7
8
7
8
RST/RST
occurs: whenever V
is below the reset threshold level; for devices with WDI, reset output
CC
asserts when WDI does not receive a rising edge within the watchdog timeout period.
CLOCK Clock Output
functionality. Two standard factory-trimmed reset levels
are available. The watchdog timer is programmable to
eight individual timeout values and may be disabled for
test purposes.
Detailed Description
The MAX7389/MAX7390 replace ceramic resonators,
crystals, and supervisory functions for microcontrollers
in 3.3V and 5V applications.
Clock Output (CLOCK)
The push-pull clock output (CLOCK) drives a ground-
connected 1kΩ load or a positive supply connected
500Ω load to within 300mV of either supply rail. CLOCK
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 section.
The MAX7389/MAX7390 provide a clock source, reset,
and watchdog functions. The watchdog timer is pin
programmable and provides watchdog timeout values
in the 16ms to 2048ms range. The MAX7389 provides a
separate watchdog output that is used as a status indi-
cator or to control safety-critical system elements. The
MAX7390 features a clock-speed switch that reduces
the output frequency by half. This functionality allows
the microcontroller to operate at reduced power and
may be used to extend the time available to perform
housekeeping tasks, such as writing data to flash during
a power failure.
The MAX7390 clock output frequency is reduced by a
factor of two by taking SPEED low. This functionality
allows the microcontroller to operate at reduced power
and may be used to extend the time available to per-
form housekeeping tasks.
The integrated reset and watchdog functions provide the
power-supply monitoring functions necessary to ensure
correct microcontroller operation. The reset circuit has
built-in power-supply transient immunity and provides
both power-on reset and power-fail or brownout reset
Reset
The reset function drives the microcontroller reset input
to prevent operation in the cases of the initial power-on
setting, low power-supply voltages, and the failed
6
_______________________________________________________________________________________
Microcontroller Clock Generator with
Watchdog
watchdog operations. Three reset output versions are
available: push-pull RST, push-pull RST, and open-drain
RST. The reset timeout period (t ) is nominally 135s.
maximum transient duration without causing a reset
pulse vs. reset comparator overdrive.
RST
Figure 1 shows the reset output (RST/RST) behavior
during power-up and brownout.
Power-On Reset (POR)
The internal power-on reset (POR) circuit detects the
power-supply voltage (V ) level at startup. The POR
Watchdog
The watchdog function provides microprocessor moni-
toring by requiring the microprocessor to toggle an out-
put pin to indicate correct operation. The WDI input
monitors the port signal and resets the watchdog timer
on receipt of a rising edge. If an edge is not received
within the required watchdog timeout period, the watch-
dog circuit initiates a reset cycle and asserts the WDO
output (MAX7389 only). The internal watchdog circuits
are reset and the watchdog timer restarts at the end of
the reset cycle (RST/RST output releases). The WDO
output remains asserted until a valid edge is received
on the WDI input, signifying correct microprocessor
operation. The WDO output can be used as a status
indicator either to the microprocessor or to an external
device, such as a fault-indicating LED or sounder. The
CC
circuit starts the oscillator when V
exceeds the reset
CC
rising threshold level (V
). The reset output remains
TH+
CC
asserted from the time V
crosses the V
and con-
TH+
tinues to be asserted for the reset timeout period (t
).
RST
Upon completion of the reset timeout, the reset output
is released. See Figure 1.
Low-Voltage Lockout
The reset output asserts whenever V
drops below the
CC
reset falling threshold, V . The difference between the
TH-
reset rising and falling threshold values is V
- (V ).
TH-
TH+
The nominal hysteresis value is 2% of the reset rising
threshold value. The reset detection circuitry provides
filtering to prevent triggering on negative voltage spikes.
See the Typical Operating Characteristics for a plot of
5
4
V
TH+
V
TH-
3
2
1
V
CCR
CLK
t
RST
RST
CLOCK STARTS ON INTERNAL
POR (V , V RISING).
TH+ CC
RST RELEASES AFTER THE
RESET TIMEOUT PERIOD.
RST ASSERTS ON RESET FALLING
VOLTAGE (V , V FALLING).
TH- CC
CLOCK STOPS.
RST CONTINUES TO
ASSERT UNTIL V
.
CCR
Figure 1. RST/RST Behavior During Power-Up and Brownout
_______________________________________________________________________________________
7
Microcontroller Clock Generator with
Watchdog
WDO output is an open-drain output. The power-up
Applications Information
Interfacing to a Microcontroller
Clock Input
condition of the WDO output is high (not asserted).
The operation of the watchdog and reset function is
illustrated in Figure 2.
The CLOCK output is a push-pull, CMOS logic output,
which directly drives any microprocessor (µP) or micro-
controller (µC) clock input. There are no impedance-
matching issues when using the MAX7389/MAX7390.
Operate the MAX7389/MAX7390 and microcontroller
(or other clock input device) from the same supply volt-
age level. Refer to the microcontroller data sheet for
clock-input compatibility with external clock signals.
The watchdog timeout period is set to one of nine possi-
ble values by pin strapping WDS1 and WDS2. Each
control input has three possible values assigned by
connection to GND, V , or V /2 (see Table 1). One
CC
CC
of the assigned values disables the watchdog function
and is intended for customer use during test. The
watchdog timer is disabled while the RST/RST output is
asserted.
The MAX7389/MAX7390 require no biasing components
or load capacitance. When using the MAX7389/
MAX7390 to retrofit a crystal oscillator, remove all biasing
components from the oscillator input.
Table 1. Watchdog Timeout Periods
WꢁTCHDOG TIMEOUT
PERIOD (ms)
WDS1
WDS2
Power-Supply Considerations
The MAX7389/MAX7390 operate with power-supply
voltages in the 2.7V to 5.5V range. Power-supply
decoupling is needed to maintain the power-supply
MIN
11
TYP
16
MꢁX
22
GND
GND
GND
GND
V
V
V
/2 = open
22
32
44
CC
CC
CC
V
44
64
88
rejection performance of the devices. Bypass V
to
CC
CC
GND with a 0.1µF surface-mount ceramic capacitor.
Mount the bypass capacitor as close to the device as
possible. If possible, mount the MAX7389/MAX7390
close to the microcontroller’s decoupling capacitor so
that additional decoupling is not required.
GND
V
V
V
/2 = open
/2 = open
/2 = open
88
128
177
354
708
1416
2828
CC
CC
CC
/2 = open
177
354
708
1416
256
V
512
CC
GND
V
1024
2048
Disabled
CC
/2 = open
V
V
CC
CC
A larger-value bypass capacitor is recommended if the
MAX7389/MAX7390 are to operate with a large capaci-
tive load. Use a bypass capacitor value of at least 1000
times that of the output load capacitance.
V
CC
Note: WDS1 or WDS2 is pulled internally to V /2 if left floating.
CC
V
CC
CLK
RST
RESET TIMEOUT PERIOD
(t
)
RST
ACTIVE
INTERNAL
WATCHDOG STATE
TRIPPED
WDI
WDO
WATCHDOG TIMEOUT
PERIOD (t
)
WDG
Figure 2. Watchdog Timing Diagram
_______________________________________________________________________________________
ꢃ
Microcontroller Clock Generator with
Watchdog
The MAX7389/MAX7390 are immune to vibration,
shock, and EMI influences and thus provide a consider-
ably more robust clock source than crystal- or ceramic-
resonator-based oscillator circuits.
Output Jitter
The MAX7389/MAX7390s’ jitter performance is given in
the Electrical Characteristics table as a peak-to-peak
value obtained by observing the output of the device for
20s with a 500MHz oscilloscope. Jitter measurements
are approximately proportional to the period of the out-
put frequency of the device. Thus, a 4MHz part has
approximately twice the jitter value of an 8MHz part.
Table 3. Reset Output Type
OUTPUT TYPE
s
A
B
C
Push-pull RST
The jitter performance of all clock sources degrades in
the presence of mechanical and electrical interference.
Push-pull RST
Open drain RST
Table 2. POR Voltage
Note: Standard values are shown in bold. Contact factory for
other output types.
POWER-ON RESET VOLTꢁGE (V
)
TH
r
M
J
±.3ꢃ
3.96
3.44
3.34
3.13
2.ꢃ9
2.82
2.5
Table ±. Clock Output Frequency
N
P
Q
S
V
X
CLOCK FREQUENCY (ꢂ
) (MHz)
ꢂꢂ
CLOCK
4
8
RD
TP
12
16
VB
WB
Note: Contact factory for other frequencies.
Note: Standard values are shown in bold. Contact factory for
other POR voltage.
Selector Guide
FREQUENCY
RESET
WꢁTCHDOG INPUT (WDI)/
POWER-FꢁIL INPUT (PFI)/
PIN-
PꢁCKꢁGE
PꢁRT
SPEED
RꢁNGE (MHz) FUNCTION WꢁTCHDOG OUTPUT (WDO) POWER-FꢁIL OUTPUT (PFO)
MAX7387
MAX7388
MAX7389
MAX7390
MAX7391
1 to 16
1 to 16
1 to 16
1 to 16
1 to 16
Yes
Yes
Yes
Yes
Yes
Yes/yes
Yes/no
Yes/yes
Yes/no
No/no
Yes/yes
No/yes
No/no
—
—
10 µMAX
8 µMAX
8 µMAX
8 µMAX
8 µMAX
—
No/no
Yes
Yes
Yes/no
Note: Other versions with different features are available. Refer to the MAX7387/MAX7388 and MAX7391 data sheets.
_______________________________________________________________________________________
9
Microcontroller Clock Generator with
Watchdog
Functional Diagram
V
CC
RST/RST
MAX7389
MAX7390
PRESCALER
RESET TIMER
POWER-ON
RESET
OSCILLATOR
CLOCK
SPEED**
WDO*
WATCHDOG
TIMER
WDI
N
WDS1
WDS2
*MAX7389 ONLY
**MAX7390 ONLY
GND
Typical Application Circuit
12V
5V
DC-DC
V
CC
V
CC
RST/RST
RST/RST
WDS1
WDS2
WDO*
WDI
I/O PORT
I/O PORT
I/O PORT
OSC1
MAX7389
MAX7390
µC
SPEED**
CLOCK
*MAX7389 ONLY
**MAX7390 ONLY
GND
Chip Information
PROCESS: BiCMOS
1ꢀ ______________________________________________________________________________________
Microcontroller Clock Generator with
Watchdog
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.)
4X S
8
8
MILLIMETERS
INCHES
DIM MIN
MAX
MAX
MIN
-
-
0.043
0.006
0.037
0.014
0.007
0.120
1.10
0.15
0.95
0.36
0.18
3.05
A
0.002
0.030
0.010
0.005
0.116
0.05
0.75
0.25
0.13
2.95
A1
A2
b
E
H
Ø0.50±0.1
c
D
e
0.0256 BSC
0.65 BSC
0.6±0.1
E
H
0.116
0.188
0.016
0°
0.120
2.95
4.78
0.41
0°
3.05
5.03
0.66
6°
0.198
0.026
6°
L
1
1
α
S
0.6±0.1
0.0207 BSC
0.5250 BSC
BOTTOM VIEW
D
TOP VIEW
A1
A2
A
c
α
e
L
b
SIDE VIEW
FRONT VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
APPROVAL
DOCUMENT CONTROL NO.
REV.
1
21-0036
J
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 ____________________ 11
© 2006 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
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