MAXIM MAX7389, MAX7390 User Manual

General Description

The MAX7389/MAX7390 replace ceramic resonators,
crystals, and supervisory functions for microcontrollers
in 3.3V and 5V applications.

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 indi­cator or to control safety-critical system elements.

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 per­form housekeeping tasks, such as writing data to flash
during a power failure.

The MAX7389/MAX7390 clock outputs are factory pro­grammed to a frequency in the 1MHz to 16MHz range.
Four standard frequencies are available. Other frequen­cies are available upon request. The maximum operating
supply current is 5.5mA with a clock frequency of 12MHz.

Unlike typical crystal and ceramic resonator oscillator
circuits, the MAX7389/MAX7390 are resistant to EMI
and vibration, and operate reliably at high tempera­tures. The high-output drive current and absence of
high-impedance nodes make the oscillator invulnerable
to dirty or humid operating conditions.

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.

Applications

White Goods Handheld Products

Automotive Portable Equipment

Appliances and Controls Microcontroller Systems

Features

♦ Robust Microcontroller Clock and Supervisor in a

Single Package

♦ Integrated Reset and Watchdog Functions

♦ Pin-Programmable Watchdog Timeout

♦ Speed Select

♦ +2.7V to +5.5V Operation

♦ Factory-Trimmed Oscillator

♦ Reset Valid Down to 1.1V Supply Voltage

♦ ±10mA Clock-Output Drive Current

♦ ±4% Total Accuracy for -40°C to +125°C

♦ ±2.75% Total Accuracy for 0°C to +85°C

♦ 5.5mA Operating Current (12MHz Version)

♦ -40°C to +125°C Temperature Range

♦ 8-Pin µMAX Surface-Mount Package

♦ 1MHz to 16MHz Factory Preset Frequency

MAX7389/MAX7390

Microcontroller Clock Generator with

Watchdog

________________________________________________________________ Maxim Integrated Products 1

19-3897; Rev 1; 2/06

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.

RST/RST

TOP VIEW

µMAX

WDI

WDOGND

1

2

87CLOCK

WDS1

WDS2

V

CC

3

4

6

5

MAX7389

Pin Configurations

Ordering Information

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.

Typical Application Circuit, Functional Diagram, and Selector
Guide appear at end of data sheet.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

WDI

SPEEDGND

1

2

87CLOCK

RST/RSTWDS1

WDS2

V

CC

TOP VIEW

3

4

6

5

MAX7390

µMAX

查询MAX7389供应商

PART TEMP RANGE

o

MAX7389srff -40

MAX7390srff -40oC to +125oC 8 µMAX U8-1

C to +125oC 8 µMAX U8-1

PIN­PACKAGE

PKG

CODE

MAX7389/MAX7390

Microcontroller Clock Generator with
Watchdog

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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.

VCCto GND...........................................................-0.3V to +6.0V

All Other Pins to GND ................................-0.3V to (V

CC

+ 0.3V)

CLOCK, RST/RST, WDO Output Current .........................±50mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.5mW/°C over +70°C) ................362mW

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

ELECTRICAL CHARACTERISTICS

(Typical Application Circuit, VCC= +2.7V to +5.5V, TA= -40°C to +125°C, 1MHz to 16MHz output frequency range, typical values at
V

CC

= +5.0V, TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

POWER REQUIREMENTS

Operating Supply Voltage V

Valid RST/RST Supply Voltage V

Operating Supply Current I

TRI-LEVEL ANALOG INPUTS: WDS1, WDS2

Input-High Voltage Level V

Input-Middle Voltage Level 0.9 VCC - 1.1V V

Input-Low Voltage Level 0.45 V

LOGIC INPUT: WDI

Input Leakage Current I

Logic-Input High Voltage V

Logic-Input Low Voltage V

PUSH-PULL LOGIC OUTPUTS: RST/RST

Output High V

Output Low V

OPEN-DRAIN LOGIC OUTPUTS: RST, PFO, WDO

Output Low V

OUTPUT: CLOCK

Output High Voltage V

Output Low Voltage V

CLOCK Accuracy f

Clock Frequency Temperature
Coefficient

Clock Frequency Supply Voltage
Coefficient

CC

CCR

LEAK

OLO

OHCISOURCE

OLCISINK

CLOCK

TA = 0°C to +85°C 1.1

TA = -40°C to +125°C 1.18

f

CC

CLOCK

f

CLOCK

Input high 0.5 µA

IH

IL

I

OH

SOURCE

I

OL

SINK

I

SINK

TA = 0°C to +85°C, VCC = 5.0V -2.75 +2.75

TA = -40°C to +125°C, VCC = 5.0V -4 +4

V

CC

T

= +25°C (Note 2) 0.67 1 %/V

A

= 12MHz 5.5

= 8MHz 4.5

= 1mA VCC - 1.5 V

= 3mA 0.05 0.4 V

= 3mA 0.05 0.4 V

= 5mA VCC - 0.3 V

= 5mA 0.3 V

= 5.0V (Note 2) 140 400 ppm/°C

2.7 5.5 V

- 0.55V V

C C

0.7 x V

CC

0.3 x V

CC

V

mA

V

V

%

MAX7389/MAX7390

Microcontroller Clock Generator with

Watchdog

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Typical Application Circuit, VCC= +2.7V to +5.5V, TA= -40°C to +125°C, 1MHz to 16MHz output frequency range, typical values at
V

CC

= +5.0V, TA= +25°C, unless otherwise noted.) (Note 1)

(

)

(

)

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2: Guaranteed by design. Not production tested.

CLOCK Duty Cycle (Note 2) 45 50 55 %

CLOCK Output Jitter

Output Rise Time t

Output Fall Time t

INTERNAL POWER-ON RESET

Reset Voltage

Reset Timeout Period t

WATCHDOG

Watchdog Timeout Period
(Figure 2)

POWER FAIL

Power-Fail Select Threshold V

VCC Monitoring Threshold

Internal Threshold

Internal Threshold Hysteresis V

PFI Monitoring Threshold

External Threshold

External Threshold Hysteresis V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Observation for 20s using a 500MHz
oscilloscope

C

R

C

F

V

V

RST

t

WDG

V

IHYSTVCC

V

EHYST

VCC rising, Table 2

TH+

VCC falling

TH-

Figures 1, 2 86 135 250 µs

WDS1 = GND, WDS2 = GND 11 16 22

WDS1 = open, WDS2 = GND 22 32 44

WDS1 = VCC, WDS2 = GND 44 64 88

WDS1 = GND, WDS2 = open 88 128 177

WDS1 = open, WDS2 = open 177 256 354

WDS1 = VCC, WDS2 = open 354 512 708

WDS1 = GND, WDS2 = V

WDS1 = open, WDS2 = V

W D S 1 = W D S 2 = V

PFI input

SEL

VCC rising 4.06 4.38 4.60 V

ITH

PFI rising 0.9 1.1 1.4 V

ETH

PFI falling 1.0 3.5 8.0 %V

310

= 10p F, 10% to 90% of ful l scal e ( N ote 2) 2.5 7.0 ns

L OA D

= 10p F, 90% to 10% of ful l scal e ( N ote 2) 2.8 7.5 ns

L OA D

V

TA = +25°C

T

= -40°C to +125°C

A

CC

CC

( w atchd og d i sab l ed )

C C

falling 1.0 2 4.0 %V

TH

- 1.5%

V

TH

- 2.5%

0.98 x
V

TH+

708 1024 1416

1416 2048 2832

0.65 x
V

CC

V

TH

+ 1.5%

V

TH

+ 2.5%

0.85 x
V

CC

ps

RMS

V

ms

V

ITH

ETH

MAX7389/MAX7390

Microcontroller Clock Generator with
Watchdog

4 _______________________________________________________________________________________

Typical Operating Characteristics

(Typical Application Circuit, VCC= +5V, f

CLOCK

= 16MHz, TA= +25°C, unless otherwise noted.)

DUTY CYCLE vs. TEMPERATURE

MAX7389 toc04

DUTY CYCLE (%)

49

50

51

52

48

TEMPERATURE (°C)

1109580655035205-10-25-40 125

CLOCK OUTPUT WAVEFORM

WITH C

L

= 10pF

MAX7389 toc05

40ns/div

CLOCK
1V/div

VCC = +3.3V

CLOCK OUTPUT WAVEFORM

WITH C

L

= 50pF

MAX7389 toc06

40ns/div

CLOCK
1V/div

VCC = +3.3V

CLOCK OUTPUT WAVEFORM

WITH C

L

= 100pF

MAX7389 toc07

40ns/div

CLOCK
1V/div

SUPPLY CURRENT vs. TEMPERATURE

MAX7389 toc08

I

CC

(mA)

2

3

4

5

1

TEMPERATURE (°C)

1109580655035205-10-25-40 125

VCC = +5V

VCC = +3.3V

SUPPLY CURRENT vs. SUPPLY VOLTAGE

MAX7389 toc09

VCC (V)

I

CC

(mA)

4.854.203.55

2

3

4

5

1

2.90 5.50

V

TH+

= +2.9V

FREQUENCY vs. SUPPLY VOLTAGE

1.020

1.010

1.000

NORMALIZED FREQUENCY

0.990

NORMALIZED TO VCC = +5V

= +2.9V

V

0.980

2.90 5.50

TH+

4.854.203.55

VCC (V)

MAX7389 toc01

1.040

FREQUENCY vs. TEMPERATURE

1.030

1.020

1.010

1.000

NORMALIZED FREQUENCY

0.990

0.980

-40 125

NORMALIZED TO TA = +25°C

TEMPERATURE (°C)

DUTY CYCLE vs. SUPPLY VOLTAGE

52

MAX7389 toc02

51

50

DUTY CYCLE (%)

49

V

1109580655035205-10-25

48

2.90 5.50
VCC (V)

TH+

4.854.203.55

MAX7389 toc03

= +2.9V