Datasheet MIC2755BMM Datasheet (MICREL)

MIC2755 Micrel

MIC2755

Battery System Supervisor

Preliminary Information

General Description

The MIC2755 is composed of multiple comparators, a reset
pulse generator, and logic. It is designed for monitoring the
battery supply of portable digital systems, including PDAs
and pagers.

The MIC2755 detects three different battery states: battery
OK, low battery, and dead battery. The reset (/RST) output is
asserted for at least 700ms when a fresh battery is inserted.
The nonmaskable interrupt output (/NMI) is asserted when
the battery voltage is below the NTH threshold, indicating that
high-power system operations should not occur. If and when
battery voltage falls below the power-off threshold (PTH), the
reset output is asserted and latched, inhibiting system opera­tion until the battery is replaced or recharged.

All three voltage thresholds are set using external resistors.
A manual reset function can be implemented by connecting
a switch directly to the power on reset/manual reset [RTH(/MR)]
input. Internal circuitry detects switch activation and gener­ates a minimum 175ms debounced reset signal. The
MIC2755’s power supply input is separate from the detector
inputs to allow it to be powered from a down-stream voltage,
such as the output of a boost converter.

Inputs and outputs can be pulled above V
absolute maximum) without adverse effects or excessive
current draw.

Supply current is typically a low 2µA. Hysteresis is included
on all voltage detectors to prevent chattering due to noise.
The MIC2755 is available in the tiny 8-lead micro-small­outline package.

(up to 7V

DD

Features

• Optimized for PDAs, pagers and
other hand-held devices.

• Detects multiple battery states:

- battery OK

- low battery

- dead battery

• Adjustable voltage thresholds

• High accuracy ±2% voltage thresholds

• Reset generation at power-on (700ms min.)

• Debounced manual reset function

• Internal logic prevents chatter if battery voltage

fluctuates

• Extremely low 2µA typical supply current

• I/Os can be pulled above VDD (7V absolute maximum)

• Immune to brief power supply transients

• Low cost

• 8-lead MSOP

Applications

• PDAs

• Pagers

• Consumer electronics

• Embedded controllers

• Portable instruments

• Data loggers

Ordering Information

Part Number Junction Temp. Range Package

MIC2755BMM –40°C to +85°C 8-pin MSOP

Typical Application

Boost or Buck

Converter

IN OUT
EN

V

BAT(OK)

V

BAT(low)

V

BAT(dead)

= 3.6V
= 3.1V

= 2.9V

SW

RESET

V

656k

344k

BAT

576k

26.7k

400k

MIC2755

VDD /POF
PTH
NTH
RTH(/MR)

/NMI
/RST
GND

100k 100k 100k

Supervised Boost Converter and Microcontroller or Microprocessor

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

February 2000 1 MIC2755

µController or

µProcessor

SUPPLY

/NMI
/RST

GND

MIC2755 Micrel

Pin Configuration

NTH
PTH

GND

Pin Description

Pin Number Pin Name Pin Function

1 RTH(/MR) Power-On Reset Threshold (Analog Input): Comparator input assigned to

2 NTH Nonmaskable Interrupt Threshold (Analog Input): Voltage monitor input

3 PTH Power-Off Threshold (Analog Input): Voltage monitor input assigned to

4 GND Ground: Power and signal return for all IC functions.
5 /POF Power-off (Output): Active-low, open-drain output. Asserted and latched

6 /NMI Nonmaskable Interrupt (Output): Active-low, open-drain output. Asserted

7 /RST Reset (Output): Active-low, open-drain output. Asserted for a minimum of

8 VDD (Analog Input): Power supply input.

1RTH(/MR)
2
3
4

8 VDD

/RST

7

/NMI

6

/POF

5

8-Lead MSOP (MM)

battery-OK condition detection. When the level on this pin first exceeds

, the reset generator cycles. The /RST output is held low for a minimum

V

REF

of 700ms and the /POF threshold output is deasserted.

assigned to “low battery” condition detection. When the level on this pin falls
below V

“dead battery” condition detection. When the level on this pin falls below
V

REF

a reset cycle occurs (V

when V
in reset until the battery is replaced and a power-on reset cycle occurs.

when V
power system operation should not be allowed.

700ms at power-on or anytime V
175ms minimum when RTH (/MR) is externally pulled low (manual reset).

, the /NMI output is asserted.

REF

, the /RST and /POF outputs are asserted. The condition is latched until

PTH

NTH

< V

< V

> V

RTH

, which is a “dead battery” condition. The system is held

REF

, which is a “low battery” condition. This indicates high-

REF

).

REF

drops below V

PTH

. Also asserted for

REF

MIC2755 2 February 2000

MIC2755 Micrel

Absolute Maximum Ratings (Note 1)

Supply Voltage (V
Input Voltage (V
Output Voltage (V
/RST Output Current (I
Storage Temperature (T

ESD Rating, Note 3 ......................................................2kV

) ..................................... –0.3V to +7V

DD

RTH

/RST

), (V

), (V

NTH

), (V

/NMI

) .......................................20mA

/RST

) ....................... –65°C to +150°C

S

) ............. –0.3V to +7V

PTH

), (V

) ........ –0.3V to +7V

/POF

Operating Ratings (Note 2)

Supply Voltage (V
Input Voltage (V
Output Voltage (V

Ambient Temperature Range (TA) ............. –40°C to +85°C

Package Thermal Resistance

1-layer PCB (θ

) .................................. +1.5V to +5.5V

DD

), (V

RTH

/RST

) ..............................................206°C/W

JA

NTH

), (V

), (V

/NMI

) ............. –0.3V to +6V

PTH

), (V

) ........ –0.3V to +6V

/POF

4-layer PCB (θJA) ..............................................113°C/W

Electrical Characteristics

VDD = 3.3V; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted
Symbol Parameter Condition Min Typ Max Units

I

DD

I

RTH(/MR)

, I

I

NTH

PTH

I

/RST, I/NMI

I

/POF

V

REF1

V

REF2

V

HYST

Reset Output (/RST)

t

/RST

t

/MR

V

/RST

Reset Input [RTH(/MR)]

V

/MRTV

t

DBNC

t

PROP

Nonmaskable Interrupt Output (/NMI)

t

PROP

V

/NMI

Power-Off Output (/POF)

t

PROP

V

/POF

Note 1. Exceeding the absolute maximum rating may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 100pF in series with 1.5k .
Note 4. VDD operating range is 1.5V to 5.5V. Output is guaranteed to be held low down to VDD = 1.2V.

Note 5.

Operating Supply Current outputs open, V

outputs open, V

RTH
RTH

, V
, V

NTH
NTH

, V

> 1.24V 2.0 4.0 µA

PTH

, V

< 1.24V 1.7 µA

PTH

, Leakage Current 5pA

, 10 nA

,

Threshold Voltage for RTH(/MR) and PTH inputs 1.215 1.240 1.265 V
Threshold Voltage for NTH inputs 1.215 1.240 1.265 V
Hysteresis Voltage on NTH 20 mV

Comparator

Reset Pulse Width 700 1200 ms
Manual Reset Pulse Width 175 300 ms
/RST Output Voltage Low, Note 4 /RST asserted, I

/RST asserted, I

= 1.6mA, VDD ≥ 1.6V 0.3 V

SINK

= 100µA, VDD ≥ 1.2V 0.4 V

SINK

Manual Reset Trip Voltage 275 310 345 mV
Debounce Time V

/MRTV(min)

Propogation Delay from (V

to RST Asserted

Propagation Delay (V

REF(max)

< V

RTH

< V

/MR

RTH(/MR)(min)

+ 100mV) < V

< V

/MRTV(max)

, Note 5 22 38 ms

– 100mV) 9 µs

NTH

< (V

REF(min)

9 µs

– 100mV)

/NMI Output Voltage Low /NMI asserted, I

/NMI asserted, I

Propagation Delay (V

– 100mV)

/POF Output Voltage Low /POF asserted, I

/POF asserted, I

t

t

t

DBNC

/RST /MR

==

32

8

. These relationships are guaranteed by design.

REF(max)

+ 100mV) < V

= 1.6mA, VDD ≥ 1.6V 0.3 V

SINK

= 100µA, VDD ≥ 1.2V 0.4 V

SINK

< (V

PTH

= 1.6mA, VDD ≥ 1.6V 0.3 V

SINK

= 100µA, VDD ≥ 1.2V 0.4 V

SINK

REF(min)

9 µs

February 2000 3 MIC2755

MIC2755 Micrel

Timing Diagram

V
V

V

BAT

V

V

/MR

/RST

/NMI

/POF

V

V

V
V

V
V
V

/MRH

/MRL

/RSTH

/RSTL
/NMIH

/NMIL

/POFH

/POFL

V

V

V

V

Block Diagram

PTH

0V

RTH

NTH

t

RST

Propagation delays not shown for clarity.
The MIC2755 ignores very brief transients. See “Application

Information” for details.

t

RST

<t

DBNC

>t

DBNC

t

/MR

NOT TO SCALE.

20mV

V

EXPANDED

BAT

VERTICALLY TO

SHOW DETAIL.

NTH

PTH

RTH(/MR)

1.24V
Ref1

1.24V
Ref2

20mV

Hysteresis

310mV

VDD

Machine

Logic-State

/NMI

/RST

/POF

GND

Oscillator

MIC2755 4 February 2000

MIC2755 Micrel

Functional Description

Typically the MIC2755 is used to monitor the battery supply
of intelligent circuits such as microcontrollers and micropro­cessors. By connecting the reset output of a MIC2755 to the
reset input of a µC or µP, the processor will be properly reset
at power-on and during power-down and low battery condi­tions. The /NMI output provides low-battery warnings to the
system. In addition, a system whose battery voltage declines
below the PTH threshold is held in reset to prevent spurious
operation. Thus the MIC2755 effectively detects three battery
states: “battery OK,” “low battery,” and “dead battery.”

Reset Output

/RST is an active-low, open-drain digital output. This output
is asserted for a minimum of 700ms at power-on and for a
minimum of 175ms when RTH(/MR) is externally pulled low,
indicating that a manual reset should be initiated. /RST is an
active-low, open-drain digital output and may be wire-ORed
with other open-drain logic signals. Most applications will
require a pull-up resistor on this pin. /RST may be pulled up
to any voltage not exceeding V

/RST(max)

higher than VDD (see “Electrical Characteristics”).

Nonmaskable Interrupt Output

/NMI is the output of a comparator that constantly compares
the level on the NTH pin with the internal voltage reference,
V

. This output is asserted when V

REF2

high-power system operation should not occur; that is, the
battery is low but not dead. Effectively, this function is an
uncommitted comparator with its inverting input connected to
the internal reference, V

, its noninverting input con-

REF2

nected to NTH, and its output on /NMI. This comparator does
not affect any other MIC2755 functions and may be used
independently.

/NMI is an active-low, open-drain digital output and may be
wire-ORed with other open-drain logic signals. Most applica­tions will require a pull-up resistor on this pin. /NMI may be
pulled up to any voltage not exceeding V
voltage is higher than VDD (see “Electrical Characteristics”).

even if this voltage is

< V

NTH

/NMI(max)

, indicating

REF2

even if this

Power-Off Output

This output and the /RST output are asserted and latched
when V

PTH

< V

, indicating a “dead battery.” The system

REF

is held in reset until the battery is replaced or recharged and
a power-on reset cycle occurs; that is, V

RTH

> V

REF1

. The
/POF output may be used to control a linear or switching
regulator, shutting down the regulator when the battery
reaches it end-of-life voltage.

/POF is an active-low, open-drain digital output and may be
wire-ORed with other open-drain logic signals. Most applica­tions will require a pull-up resistor on this output. /POF may
be pulled up to any voltage not exceeding V

/POF(max)

even if
this voltage is higher than VDD (see “Electrical Characteris­tics”).

Power-On Reset

The RTH(/MR) and PTH inputs work together to provide
predictable battery monitoring with user-programmable hys­teresis and without chatter. The /RST output is asserted for
a minimum of 700ms at power-on. Power-on is determined by
RTH(/MR) exceeding V

. Once this event has occurred,

REF1

the internal logic ignores further transitions on the RTH(/MR)
input, instead monitoring for a low voltage on PTH or the
manual reset condition. If V

drops below V

PTH

REF1

, the /POF
and /RST outputs are asserted and latched, holding the
system in its reset state.

Manual Reset

An internal circuit monitors RTH(/MR), comparing it to an
internal 310mV reference, V
below V

/MRTV,

and V

is still above V

PTH

. When RTH(/MR) is pulled

/MRTV

REF1

, the internal
circuitry initiates a manual reset cycle and asserts /RST for at
least 175ms. A momentary push-button switch is typically
connected such that RTH(/MR) is forced to ground when the
switch contacts close. This switch is internally debounced.
Each closure of the switch longer than t

results in a

DBNC

single output pulse of no less than 175ms and no more than
300ms being generated. (The manual reset pulse is derived
from the same oscillator and counter as t
t

is always equal to one fourth of t

/MR

/RST

. The length of

/RST

.) This prevents a
user who may hold the switch closed from keeping the system
in reset for an extended period of time.

February 2000 5 MIC2755

MIC2755 Micrel

V=V

R6 R7

R7

BAT(OK)

REF

+











Applications Information

Outputs

Since the MIC2755 outputs are open-drain MOSFETs, most
applications will require pull-up resistors. The value of the
resistors should not be too large or leakage effects may
dominate.

Programming Thresholds

There are separate resistive-divider configurations for cir­cuits that require or do not require manual reset capability.

Configuration Without Manual Reset

See Figure 1. The battery-OK threshold is calculated using:

R1 R2 R3 R4

VV

BAT(OK)

=

REF






4

R

+++

The low-battery threshold is calculated using:

R1 R2 R3 R4

+++

VV

BAT(low) REF

=






R3 R4

+

The dead-battery threshold is calculated using:

R1 R2 R3 R4

+++

VV

BAT(dead) REF

=






R2 R3 R4

++

where, for all equations:

V

= 1.24V

REF

In order to provide the additional criteria needed to solve for
the resistor values, the resistors can be selected such that
they have a given total value, that is, R1 + R2 + R3 + R4 =
R

. A value such as 1MΩ for R

total

total

because it draws minimum battery current per resistor ladder
but has no significant effect on system accuracy.

When working with large resistors, a small amount of leakage
current can cause voltage offsets that degrade system accu­racy. The maximum recommended total resistance from
V

to ground is 3MΩ.

BAT

V

BAT

R1

572k

R2

28k

R3

55.6k

R4

344k

MIC2755

VDD /POF
PTH
NTH
RTH(/MR)

/NMI
/RST
GND

Figure 1. Example Circuit without Manual Reset

Once the desired trip points are determined, set the V
threshold first.

For a typical single-cell lithium ion battery, 3.6V is a reason­able “OK threshold” because at 3.6V the battery is moder­ately charged. Solving for R4:

1M



V 3.6V 1.24V

BAT(OK)

==

Ω





R

4
















is a reasonable value

V

BAT

100k 100k100k

POF
NMI
RST

BAT(OK)






To determine the resistor values for V

BAT(low)

threshold, set

R4 = 344kΩ and solve for R3.

V = 3.1V=1.24V

BAT(low)






R+R4






3

1M

Ω

R3 = 56k

Once R3 and R4 are determined, the equation for V

BAT(dead)

can be used to determine R2. A single lithium-ion cell should
not be discharged below 2.5V. Many applications limit the
drain to 2.9V. Using 2.9V for the V

BAT(dead)

threshold allows

calculating the following resistor values.

1M

V = 2.9V=1.24V

BAT(dead)






R2+ 55.6k+ 344k

Ω






R2 = 27.4k
R1 = 1MΩ – R2 – R3 – R4 = 572k

Configuration With Manual Reset

See Figure 2. To use manual reset, the MIC2755 requires a
separate resistor ladder for the switch and fresh-battery
threshold. The remaining two thresholds are set by the three­resistor ladder.

SW

V

BAT

656k

344k

R6

R7

R8

573k

R9

26.7k

R10

400k

MIC2755

VDD /POF
PTH
NTH
RTH(/MR)

/NMI
/RST
GND

100k 100k100k

V

BAT

POF
NMI
RST

Figure 2. Example Circuit with Manual Reset

R8+R9+R10

V=V

BAT(low) REF

V=V

BAT(dead) REF






R8+R9+R10






R10

R9+R10











where, for all equations:

V

= 1.24V

REF

Once the desired trip points are determined, set R6 + R7 =
1MΩ and solve for R7.

1M

Ω



V = 3.6V=1.24V

BAT(fresh)











R7

R7 = 344k
R6 = 1MΩ – 344k = 656k

The remaining resistor values are solved in a similar manner
as the above.

1MΩ = R8 + R9 + R10

R4 = 344kΩ

MIC2755 6 February 2000

MIC2755 Micrel

1M

Ω



V = 3.1V=1.24V

BAT(low)





R10






R10 = 400k
1MΩ = R10+R11

V = 2.9V=1.24V

BAT(dead)






R9+ 400k






1M

Ω

R9 = 27k
R8 = 1MΩ – R9 – R10 = 573k

The accuracy of the resistors can be chosen based upon the
accuracy required by the system.

Input Transients

The MIC2755 is inherently immune to very short negative­going “glitches.” Very brief transients may cross the V
or V

BAT(dead)

thresholds without tripping the output(s).

BAT(lo)

As shown in Figures 3 and 4, the narrower the transient, the
deeper the threshold overdrive that will be ignored by the
MIC2755. The graph represents the typical allowable tran­sient duration for a given amount of threshold overdrive that
will not cause the corresponding output to change state.

Alternate Configurations

The MIC2755 can be used in a variety of ways. It is especially
flexible due to the fact that the NMI comparator is completely
independent. There are other useful configuration besides a
three-state battery monitor. The NMI comparator can be used
to provide power-fail indication (PFI/PFI), monitor an auxiliary
battery (LBI/LBO), or detect the presence of an ac adapter.

Voltage Supervisor and Backup Battery Monitor

Figure 5 illustrates the MIC2755 being used as a voltage
supervisor and a battery monitor in a 3.3V system with a
Lithium coin-cell backup. The primary voltage monitor is
configured as a voltage supervisor with a nominal trip point of

3.034V and 33mV of hysteresis as set by R1, R2, and R3. The
NMI comparator is used to detect a low-battery condition so
the system is aware that the backup battery is discharged. In
this example, the /NMI output will be asserted if battery
voltage falls below 2.2V. Manual reset capability can be
added as discussed in the

With Manual Reset

sections.

Manual Reset

and

Configuration

This same configuration can be used to detect the presence
of an auxiliary power source such as an ac adapter instead of
monitoring a battery. R4 and R5 would be selected such that
the /NMI output is deasserted when the proper input voltage
is applied.

Voltage Supervisor with Power Fail Warning

Figure 6 illustrates the MIC2755 being used as a voltage
supervisor and a power-fail detector in a 3.3V system. The
primary voltage monitor is configured as a voltage supervisor

Input Transient

200
180
160
140
120
100

MAX. TRANSIENT DURATION (µs)

RESET COMP. OVERDRIVE, V

Response (V

80
60
40
20

0

0 5 10 15 20 25 30

POF

REF–VPTH

)

(mV)

Figure 3. Input Transient Response

Input Transient

120

100

MAX. TRANSIENT DURATION (µs)

RESET COMP. OVERDRIVE, V

Response (V

80

60

40

20

0

0 5 10 15 20 25 30 35 40 45

)

NMI

REF–VNTH

(mV)

Figure 4. Input Transient Response

with a nominal trip point of 3.034V and 33mV of hysteresis as
set by R1, R2, and R3. The NMI comparator is used to detect
an impending power failure such as a low-battery condition or
ac power outage. The /NMI output will be asserted if the input
voltage to the LDO regulator falls below 3.55V. (The MIC5245
has a specified maximum dropout of 250mV at 150mA output
current. If the input voltage falls below 3.55V, the output may
droop.)

By monitoring the input of the LDO regulator, the system
receives the earliest warning of an impending power loss.
Manual reset capability can be added as discussed in the

Manual Reset

and

Configuration With Manual Reset

sec-

tions.

Supervised Boost Converter and Microcontroller or
Microprocessor

In Figures 7 and 8, the MIC2755 is used to monitor the battery
and the MIC3172 is used to maintain the output voltage at

3.3V by boosting the input voltage. When the Li-ion battery
voltage drops to 3.1V, the MIC2755 alerts the microcontroller
or the microprocessor. When the battery voltage drops to

2.9V, the MIC2755 turns off the MIC3172.

February 2000 7 MIC2755

MIC2755 8 February 2000

MIC2755

PTH

RTH(/MR)

NTH

VDD /POF

/RST

/NMI

3.3V

Power Rail

Power Fail

Warning Flag

System

Reset

GND

V

MAIN

R4

436k

R5

564k

R1

1.77M

R2

13.2k

R3

1.21M

R

PULLUP

R

PULLUP

R

PULLUP

MIC5205-3.3

EN

IN OUT

GND

Backup

Power

Lithium

Coin

Cell

MIC2755

PTH

RTH(/MR)

NTH

VDD /POF

/RST

/NMI

3.3V

Power Rail

Power Fail

Warning Flag

System

Reset

GND

V

BAT

R4

651k

R5

349k

R1

1.77M

R2

13.2k

R3

1.21M

R

PULLUP

R

PULLUP

R

PULLUP

MIC5245-3.3

EN

IN OUT

GND

MIC2755 Micrel

Figure 5. Voltage Supervisor and Backup Battery Monitor

Figure 6. Voltage Supervisor With Power Fail Warning

February 2000 9 MIC2755

PGND1

MIC3172

MIC2755

SGND

COMP

EN

IN

PTH

RTH(/MR)

NTH

VDD

µController or

µProcessor

RST

GND

NMI

SUPPLY

/POF

8

1

2

3

5
6
7
4

/RST

/NMI

GND

FB

L1b
33µH

C7 10µF 16V

L1a

33µH

SW

PGND2

C5

0.01µF

R7

4.75k

R6
100k

V

BAT(OK)

= 3.6V

V

BAT(low)

= 3.1V

V

BAT(dead)

= 2.9V

R1

569k

R2

28k

C6
3300pF

C1
10µF
16V

R3

55.6k
R4

344k

Li-Ion

Cell

R10

3.01k

R11

1.82k

C3
220µF
10V

C2
220µF
10V

C4

0.1µF
R8

100k

3.3V @ 200mA

R9

100k

PGND1

MIC3172

MIC2755

SGND

COMP

EN

IN

PTH

RTH(/MR)

NTH

VDD

µController or

µProcessor

RST

GND

NMI

SUPPLY

/POF

8

1

2

3

5
6
7
4

/RST

/NMI

GND

FB

L1b
33µH

C2 10µF 16V

L1a

33µH

SW

PGND2

C5

0.01µF

R8

4.75k

R7
100k

C6
3300pF

C1
10µF
16V

R4

656k

R5

344k

Li-Ion

Cell

R1

576k

SW

R2

26.7k

R3

400k

R11

3.01k

R12

1.82k

C4
220µF
10V

C3
220µF
10V

C5

0.1µF
R9

100k

R10

100k

V

BAT(OK)

= 3.6V

V

BAT(low)

= 3.1V

V

BAT(dead)

= 2.9V

3.3V @ 200mA

MIC2755 Micrel

Figure 7. Typical Application Without Manual Reset

Figure 8. Typical Application With Manual Reset

MIC2755 Micrel

Package Information

0.122 (3.10)

0.112 (2.84)

0.036 (0.90)

0.032 (0.81)

0.012 (0.03)

0.0256 (0.65) TYP

0.199 (5.05)

0.187 (4.74)

0.120 (3.05)

0.116 (2.95)

0.043 (1.09)

0.038 (0.97)

0.012 (0.30) R

0.008 (0.20)

0.004 (0.10)

8-Lead MSOP (MM)

5° MAX

0° MIN

DIMENSIONS:

INCH (MM)

0.007 (0.18)

0.005 (0.13)

0.012 (0.03) R

0.039 (0.99)

0.035 (0.89)

0.021 (0.53)

MIC2755 10 February 2000

MIC2755 Micrel

February 2000 11 MIC2755

MIC2755 Micrel

MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 [phone] FAX + 1 [phone] WEB http://www.micrel.com

This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or

other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.

© 2000 Micrel Incorporated

MIC2755 12 February 2000