1997 1 MIC2571
MIC2571 Micrel
MIC2571
Single-Cell Switching Regulator
Final Information
General Description
Micrel’s MIC2571 is a micropower boost switching regulator
that operates from one alkaline, nickel-metal-hydride cell, or
lithium cell.
The MIC2571 accepts a positive input voltage between 0.9V
and 15V. Its typical no-load supply current is 120µA.
The MIC2571 is available in selectable fixed output or adjust-
able output versions. The MIC2571-1 can be configured for
2.85V, 3.3V, or 5V by connecting one of three separate
feedback pins to the output. The MIC2571-2 can be config-
ured for an output voltage ranging between its input voltage
and 36V, using an external resistor network.
The MIC2571 has a fixed switching frequency of 20kHz. An
external SYNC connection allows the switching frequency to
be synchronized to an external signal.
The MIC2571 requires only four components (diode, induc-
tor, input capacitor and output capacitor) to implement a
boost regulator. A complete regulator can be constructed in
a 0.3 in2 area.
All versions are available in an 8-lead MSOP with an operat-
ing range from –40°C to +85°.
Typical Applications
Features
• Operates from a single-cell supply
0.9V to 15V operation
• 120µA typical quiescent current
• Complete regulator fits 0.3 in2 area
• 2.85V/3.3V/5V selectable output voltage (MIC2571-1)
• Adjustable output up to 36V (MIC2571-2)
• 1A current limited pass element
• Frequency synchronization input
• 8-lead MSOP package
Applications
• Pagers
• LCD bias generator
• Battery-powered, hand-held instruments
• Palmtop computers
• Remote controls
• Detectors
• Battery Backup Supplies
Single-Cell to 5V DC-to-DC Converter
IN SW
GND
MIC2571-1
C2
47µF
16V
5V/5mA
C1*
47µF
16V
1V to1.5V
1 Cell 2.85V
3.3V
5V
2
4
5
6
1
7
8
L1
150µH
SYNC
D1
MBR0530
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in
2
excluding C1
Single-Cell to 3.3V DC-to-DC Converter
IN SW
GND
MIC2571-1
C2
47µF
16V
3.3V/8mA
C1*
47µF
16V
1V to1.5V
1 Cell 2.85V
3.3V
5V
2
4
5
6
1
7
8
L1
150µH
SYNC
D1
MBR0530
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in
2
excluding C1
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
MIC2571 Micrel
MIC2571 2 1997
Ordering Information
Part Number Temperature Range Voltage Frequency Package
MIC2571-1BMM –40°C to +85°C Selectable* 20kHz 8-lead MSOP
MIC2571-2BMM –40°C to +85°C Adjustable 20kHz 8-lead MSOP
* Externally selectable for 2.85V, 3.3V, or 5V
Pin Configuration
1
2
3
4
8
7
6
5
SW
GND
NC
5V
IN
SYNC
2.85V
3.3V
MIC2571-1
Selectable Voltage
20kHz Frequency
1
2
3
4
8
7
6
5
IN
SYNC
FB
NC
SW
GND
NC
NC
MIC2571-2
Adjustable Voltage
20kHz Frequency
8-Lead MSOP (MM)
Pin Description
Pin No. (Version†) Pin Name Pin Function
1 SW Switch: NPN output switch transistor collector.
2 GND Power Ground: NPN output switch transistor emitter.
3 NC Not internally connected.
4 (-1) 5V 5V Feedback (Input): Fixed 5V feedback to internal resistive divider.
4 (-2) NC Not internally connected.
5 (-1) 3.3V 3.3V Feedback (Input): Fixed 3.3V feedback to internal resistive divider.
5 (-2) NC Not internally connected.
6 (-1) 2.85V 2.85V Feedback (Input): Fixed 2.85V feedback to internal resistive divider.
6 (-2) FB Feedback (Input): 0.22V feedback from external voltage divider network.
7 SYNC Synchronization (Input): Oscillator start timing. Oscillator synchronizes to
falling edge of sync signal.
8 IN Supply (Input): Positive supply voltage input.
† Example: (-1) indicates the pin description is applicable to the MIC2571-1 only.
1997 3 MIC2571
MIC2571 Micrel
Electrical Characteristics
VIN = 1.5V; TA = 25°C, bold indicates –40°C≤ TA≤ 85°C; unless noted
Parameter Condition Min Typ Max Units
Input Voltage Startup guaranteed, ISW = 100mA 15 V
0.9 V
2.7
3.14
4.75
3.0
3.47
5.25
208 232
Quiescent Current Output switch off 120 µA
Fixed Feedback Voltage MIC2571-1; V2.85V pin = VOUT, ISW = 100mA 2.85 V
MIC2571-1; V3.3V pin = VOUT, ISW = 100mA 3.30 V
MIC2571-1; V5V pin = VOUT, ISW = 100mA 5.00 V
Reference Voltage MIC2571-2, [adj. voltage versions], ISW = 100mA, Note 1 220 mV
Comparator Hysteresis MIC2571-2, [adj. voltage versions] 6 mV
Output Hysteresis MIC2571-1; V2.85V pin = VOUT, ISW = 100mA 65 mV
MIC2571-1; V3.3V pin = VOUT, ISW = 100mA 75 mV
MIC2571-1; V5V pin = VOUT, ISW = 100mA 120 mV
Feedback Current MIC2571-1; V2.85V pin = VOUT 4.5 µA
MIC2571-1; V3.3V pin = VOUT 4.5 µA
MIC2571-1; V5V pin = VOUT 4.5 µA
MIC2571-2, [adj. voltage versions]; VFB = 0V 25 nA
Reference Line Regulation 1.0V ≤ VIN ≤ 12V 0.35 %/V
Switch Saturation Voltage VIN = 1.0V, ISW = 200mA 200 mV
VIN = 1.2V, ISW = 600mA 400 mV
VIN = 1.5V, ISW = 800mA 500 mV
Switch Leakage Current Output switch off, VSW = 36V 1 µA
Oscillator Frequency MIC2571-1, -2; ISW = 100mA 20 kHz
Maximum Output Voltage 36 V
Sync Threshold Voltage 0.7 V
Switch On Time 35 µs
Currrent Limit 1.1 A
Duty Cycle VFB < VREF, ISW = 100mA 67 %
General Note: Devices are ESD protected; however, handling precautions are recommended.
Note 1: Measured using comparator trip point.
Absolute Maximum Ratings
Supply Voltage (VIN) ..................................................... 18V
Switch Voltage (VSW) .................................................... 36V
Switch Current (ISW) ....................................................... 1A
Sync Voltage (VSYNC) .................................... –0.3V to 15V
Storage Temperature (TA) ....................... –65°C to +150°C
MSOP Power Dissipation (PD) ................................ 250mW
Operating Ratings
Supply Voltage (VIN) .................................... +0.9V to +15V
Ambient Operating Temperature (TA) ........ –40°C to +85°C
Junction Temperature (TJ) ....................... –40°C to +125°C
MSOP Thermal Resistance (θJA) .......................... 240°C/W
MIC2571 Micrel
MIC2571 4 1997
Typical Characteristics
0
0.2
0.4
0.6
0.8
1.0
0 0.2 0.4 0.6 0.8 1.0
SWITCH CURRENT (A)
SWITCH VOLTAGE (V)
Switch Saturation Voltage
TA = –40°C
1.4V
1.3V
1.1V
1.2V
VIN = 1.0V 0
0.2
0.4
0.6
0.8
1.0
0 0.2 0.4 0.6 0.8 1.0
SWITCH CURRENT (A)
SWITCH VOLTAGE (V)
Switch Saturation Voltage
TA = 25°C
V
IN
= 0.9V
1.0V
1.1V
1.2V
1.3V
1.4V
0
0.2
0.4
0.6
0.8
1.0
0 0.2 0.4 0.6 0.8 1.0
SWITCH CURRENT (A)
SWITCH VOLTAGE (V)
Switch Saturation Voltage
TA = 85°C1.2V
1.0V
1.1V
VIN = 0.9V
1.4V 1.3V
15
20
25
30
-60 -30 0 30 60 90 120 150
OSC. FREQUENCY (kHz)
TEMPERATURE (°C)
Oscillator Frequency
vs. Temperature
VIN = 1.5V
ISW = 100mA
50
55
60
65
70
75
-60 -30 0 30 60 90 120 150
DUTY CYCLE (%)
TEMPERATURE (°C)
Oscillator Duty Cycle
vs. Temperature
VIN = 1.5V
ISW = 100mA
50
75
100
125
150
175
200
-60 -30 0 30 60 90 120 150
QUIESCENT CURRENT (µA)
TEMPERATURE (°C)
Quiescent Current
vs. Temperature
VIN = 1.5V
0
2
4
6
8
10
-60 -30 0 30 60 90 120 150
FEEDBACK CURRENT (µA)
TEMPERATURE (°C)
Feedback Current
vs. Temperature
VIN = 1.5V
MIC2571-1
0
10
20
30
40
50
-60 -30 0 30 60 90 120 150
FEEDBACK CURRENT (nA)
TEMPERATURE (°C)
Feedback Current
vs. Temperature
VIN = 2.5V
MIC2571-2
0
25
50
75
100
125
150
175
200
0246810
QUIESCENT CURRENT (µA)
SUPPLY VOLTAGE (V)
Quiescent Current
vs. Supply Voltage
–40°C
+85°C
+25°C
0
0.25
0.50
0.75
1.00
1.25
1.50
1.75
-60 -30 0 30 60 90 120 150
CURRENT LIMIT (A)
TEMPERATURE (°C)
Output Current Limit
vs. Temperature
0.01
0.1
1
10
100
1000
-60 -30 0 30 60 90 120 150
SWITCH LEAKAGE CURRENT (nA)
TEMPERATURE (°C)
Switch Leakage Current
vs. Temperature
0
25
50
75
100
125
150
-60 -30 0 30 60 90 120 150
OUTPUT HYSTERESIS (mV)
TEMPERATURE (°C)
Output Hysteresis
vs. Temperature
VOUT = 2.85V
3.3V
5V
1997 5 MIC2571
MIC2571 Micrel
Block Diagrams
Oscillator
0.22V
Reference Driver
IN
V
BATT
2.85V GND
SW
SYNC
3.3V5V
V
OUT
MIC2571-1
Selectable Voltage Version with External Components
Oscillator
0.22V
Reference Driver
IN
V
BATT
GND
SW
SYNC
MIC2571-2
V
OUT
FB
Adjustable Voltage Version with External Components
MIC2571 Micrel
MIC2571 6 1997
Functional Description
The MIC2571 switch-mode power supply (SMPS) is a gated
oscillator architecture designed to operate from an input
voltage as low as 0.9V and provide a high-efficiency fixed or
adjustable regulated output voltage. One advantage of this
architecture is that the output switch is disabled whenever the
output voltage is above the feedback comparator threshold
thereby greatly reducing quiescent current and improving
efficiency, especially at low output currents.
Refer to the Block Diagrams for the following discription of
typical gated oscillator boost regulator function.
The bandgap reference provides a constant 0.22V over a
wide range of input voltage and junction temperature. The
comparator senses the output voltage through an internal or
external resistor divider and compares it to the bandgap
reference voltage.
When the voltage at the inverting input of the comparator is
below 0.22V, the comparator output is high and the output of
the oscillator is allowed to pass through the AND gate to the
output driver and output switch. The output switch then turns
on and off storing energy in the inductor. When the output
switch is on (low) energy is stored in the inductor; when the
switch is off (high) the stored energy is dumped into the output
capacitor which causes the output voltage to rise.
When the output voltage is high enough to cause the com-
parator output to be low (inverting input voltage is above
0.22V) the AND gate is disabled and the output switch
remains off (high). The output switch remains disabled until
the output voltage falls low enough to cause the comparator
output to go high.
There is about 6mV of hysteresis built into the comparator to
prevent jitter about the switch point. Due to the gain of the
feedback resistor divider the voltage at VOUT experiences
about 120mV of hysteresis for a 5V output.
Appications Information
Oscillator Duty Cycle and Frequency
The oscillator duty cycle is set to 67% which is optimized to
provide maximum load current for output voltages approxi-
mately 3× larger than the input voltage. Other output voltages
are also easily generated but at a small cost in efficiency. The
fixed oscillator frequency (options -1 and -2) is set to 20kHz.
Output Waveforms
The voltage waveform seen at the collector of the output
switch (SW pin) is either a continuous value equal to VIN or a
switching waveform running at a frequency and duty cycle set
by the oscillator. The continuous voltage equal to VIN
happens when the voltage at the output (VOUT) is high
enough to cause the comparator to disable the AND gate. In
this state the output switch is off and no switching of the
inductor occurs. When VOUT drops low enough to cause the
comparator output to change to the high state the output
switch is driven by the oscillator. See Figure 1 for typical
voltage waveforms in a boost application.
5V
0V
5V
0mA
IPEAK
VIN
Supply
Voltage
Peak
Current
Output
Voltage
Time
Figure 1. Typical Boost Regulator Waveforms
Synchronization
The SYNC pin is used to synchronize the MIC2571 to an
external oscillator or clock signal. This can reduce system
noise by correlating switching noise with a known system
frequency. When not in use, the SYNC pin should be
grounded to prevent spurious circuit operation. A falling edge
at the SYNC input triggers a one-shot pulse which resets the
oscillator. It is possible to use the SYNC pin to generate
oscillator duty cycles from approximately 20% up to the
nominal duty cycle.
Current Limit
Current limit for the MIC2571 is internally set with a resistor.
It functions by modifying the oscillator duty cycle and fre-
quency. When current exceeds 1.2A, the duty cycle is
reduced (switch on-time is reduced, off-time is unaffected)
and the corresponding frequency is increased. In this way
less time is available for the inductor current to build up while
maintaining the same discharge time. The onset of current
limit is soft rather than abrupt but sufficient to protect the
inductor and output switch from damage. Certain combina-
tions of input voltage, output voltage and load current can
cause the inductor to go into a continuous mode of operation.
This is what happens when the inductor current can not fall to
zero and occurs when:
duty cycle V + V – V
V + V – V
OUT DIODE IN
OUT DIODE SAT
≤
Time
Inductor Current
Current "ratchet"
without current limit
Current limit threshold
Continuous current
Discontinuous current
Figure 2. Current Limit Behavior
1997 7 MIC2571
MIC2571 Micrel
Figure 2 shows an example of inductor current in the continu-
ous mode with its associated change in oscillator frequency
and duty cycle. This situation is most likely to occur with
relatively small inductor values, large input voltage variations
and output voltages which are less than ~3× the input voltage.
Selection of an inductor with a saturation threshold above
1.2A will insure that the system can withstand these condi-
tions.
Inductors, Capacitors and Diodes
The importance of choosing correct inductors, capacitors and
diodes can not be ignored. Poor choices for these compo-
nents can cause problems as severe as circuit failure or as
subtle as poorer than expected efficiency.
a.
b.
c.
Inductor Current
Time
Figure 3. Inductor Current: a. Normal,
b. Saturating and c. Excessive ESR
Inductors
Inductors must be selected such that they do not saturate
under maximum current conditions. When an inductor satu-
rates, its effective inductance drops rapidly and the current
can suddenly jump to very high and destructive values.
Figure 3 compares inductors with currents that are correct
and unacceptable due to core saturation. The inductors have
the same nominal inductance but Figure 3b has a lower
saturation threshold. Another consideration in the selection
of inductors is the radiated energy. In general, toroids have
the best radiation characteristics while bobbins have the
worst. Some bobbins have caps or enclosures which signifi-
cantly reduce stray radiation.
The last electrical characteristic of the inductor that must be
considered is ESR (equivalent series resistance). Figure 3c
shows the current waveform when ESR is excessive. The
normal symptom of excessive ESR is reduced power transfer
efficiency. Note that inductor ESR can be used to the
designers advantage as reverse battery protection (current
limit) for the case of relatively low output power one-cell
designs. The potential for very large and destructive currents
exits if a battery in a one-cell application is inserted back-
wards into the circuit. In some applications it is possible to
limit the current to a nondestructive (but still battery draining)
level by choosing a relatively high inductor ESR value which
does not affect normal circuit performance.
Capacitors
It is important to select high-quality, low ESR, filter capacitors
for the output of the regulator circuit. High ESR in the output
capacitor causes excessive ripple due to the voltage drop
across the ESR. A triangular current pulse with a peak of
500mA into a 200mΩ ESR can cause 100mV of ripple at the
output due the capacitor only. Acceptable values of ESR are
typically in the 50mΩ range. Inexpensive aluminum electro-
lytic capacitors usually are the worst choice while tantalum
capacitors are typically better. Figure 4 demonstrates the
effect of capacitor ESR on output ripple voltage.
4.75
5.00
5.25
0 500 1000 1500
OUTPUT VOLTAGE (V)
TIME (µs)
Figure 4. Output Ripple
Output Diode
Finally, the output diode must be selected to have adequate
reverse breakdown voltage and low forward voltage at the
application current. Schottky diodes typically meet these
requirements.
Standard silicon diodes have forward voltages which are too
large except in extremely low power applications. They can
also be very slow, especially those suited to power rectifica-
tion such as the 1N400x series, which affects efficiency.
Inductor Behavior
The inductor is an energy storage and transfer device. Its
behavior (neglecting series resistance) is described by the
following equation:
I = V
L t×
where:
V = inductor voltage (V)
L = inductor value (H)
t = time (s)
I = inductor current (A)
If a voltage is applied across an inductor (initial current is
zero) for a known time, the current flowing through the
inductor is a linear ramp starting at zero, reaching a maximum
value at the end of the period. When the output switch is on,
the voltage across the inductor is:
V = V – V
1INSAT
MIC2571 Micrel
MIC2571 8 1997
When the output switch turns off, the voltage across the
inductor changes sign and flies high in an attempt to maintain
a constant current. The inductor voltage will eventually be
clamped to a diode drop above VOUT. Therefore, when the
output switch is off, the voltage across the inductor is:
V = V + V – V
2OUT DIODE IN
For normal operation the inductor current is a triangular
waveform which returns to zero current (discontinuous mode)
at each cycle. At the threshold between continuous and
discontinuous operation we can use the fact that I1 = I2 to get:
V t = V t
11 2 2
××
V
V = tt
1
2
2
1
This relationship is useful for finding the desired oscillator
duty cycle based on input and output voltages. Since input
voltages typically vary widely over the life of the battery, care
must be taken to consider the worst case voltage for each
parameter. For example, the worst case for t1 is when VIN is
at its minimum value and the worst case for t2 is when VIN is
at its maximum value (assuming that VOUT, VDIODE and VSAT
do not change much).
To select an inductor for a particular application, the worst
case input and output conditions must be determined. Based
on the worst case output current we can estimate efficiency
and therefore the required input current. Remember that this
is
power
conversion, so the worst case average input current
will occur at maximum output current and minimum input
voltage.
Average I = V I
V Efficiency
IN(max) OUT OUT(max)
IN(min)
×
×
Referring to Figure 1, it can be seen the peak input current will
be twice the average input current. Rearranging the inductor
equation to solve for L:
L = V
I t1
×
L = V
2 Average I t
IN(min)
IN(max) 1
××
where t = duty cycle
f
1OSC
To illustrate the use of these equations a design example will
be given:
Assume:
MIC2571-1 (fixed oscillator)
VOUT = 5V
IOUT(max) =5mA
VIN(min) = 1.0V
efficiency = 75%.
Average I = 5V 5mA
1.0V 0.75 = 33.3mA
IN(max) ××
L = 1.0V 0.7
2 33.3mA 20kHz
×
××
L = 525µH
Use the next lowest standard value of inductor and verify that
it does not saturate at a current below about 75mA
(< 2 × 33.3mA).
1997 9 MIC2571
MIC2571 Micrel
GND 5V
SW
MIC2571
SYNC
U1 Micrel MIC2571-1BMM
C1 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C2 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
D1 Motorola MBR0530T1
L1 Coilcraft DO1608C-154 DCR = 1.7Ω
7
4
1
2
8
IN
C2
47µF
16V
VOUT
5V/5mA
1V to 1.5V
1 Cell C1*
47µF
16V
D1
MBR0530
L1
150µH
* Needed if battery is more than 4" away from MIC2571
Example 1. 5V/5mA Regulator
GND
3.3V
SW
MIC2571
SYNC
U1 Micrel MIC2571-1BMM
C1 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C2 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
D1 Motorola MBR0530T1
L1 Coilcraft DO1608C-154 DCR = 1.7Ω
7
5
1
2
8
IN
C2
47µF
16V
VOUT
3.3V/8mA
1V to 1.5V
1 Cell C1*
47µF
16V
D1
MBR0530
L1
150µH
* Needed if battery is more than 4" away from MIC2571
Example 2. 3.3V/8mA Regulator
GND FB
SW
MIC2571
SYNC
U1 Micrel MIC2570-2BMM
C1 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C2 Sprague 594D156X0025C2T Tantalum ESR = 0.22Ω
D1 Motorola MBRA0530T1
L1 Coilcraft DO1608C-154 DCR = 1.7Ω
7
6
1
2
8
IN
C2
15µF
25V
V
OUT
12V/2mA
1.0V to 1.5V
1 Cell C1*
47µF
16V
D1
MBR0530
L1
150µH
R2
1M
1%
R1
20k
1%
* Needed if battery is more than 4" away from MIC2571
V
OUT
= 0.22V (1 + R2/R1)
Example 3. 12V/40mA Regulator
Application Examples
MIC2571 Micrel
MIC2571 10 1997
GND 5V
SW
MIC2571
SYNC
U1 Micrel MIC2571-1BMM
C1 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C2 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C3 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C4 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
D1 Motorola MBR0530T1
D2 Motorola MBR0530T1
D3 Motorola MBR0530T1
L1 Coilcraft DO1608C-154 DCR = 1.7Ω
7
4
1
2
8
IN
C2
47µF
16V
VOUT/+IOUT
5V/2mA
1V to 1.5V
1 Cell C1*
47µF
16V
D1
MBR0530
L1
150µH
* Needed if battery is more than 4" away from MIC2571
C3
47µF
16V
D2
MBR0530
D3
MBR0530 R1
220k C4
47µF
16V –VOUT/–IOUT
–5V/2mA
–IOUT ≤ +IOUT
Example 4. ±5V/2mA Regulator
GND 5V
SW
MIC2571
SYNC
U1 Micrel MIC2571-1BMM
C1 AVX TPSD107M010R0100 Tantalum ESR = 0.1Ω
C2 AVX TPSD107M010R0100 Tantalum ESR = 0.1Ω
D1 Motorola MBRA140T3
L1 Coilcraft DO3308P-473 DCR = 0.32Ω
7
4
1
2
8
IN
C2
100µF
10V
VOUT
5V/15mA
1V to 1.5V
1 Cell
C1
100µF
10V
D1
MBRA140
L1
47µH
R1
51k
Q1
2N3906
Minimum Start-Up Supply Voltage
VIN = 1V, ILOAD = 0A
VIN = 1.2V, ILOAD = 15mA
Example 5. 5V/15mA Regulator
GND FB
SW
MIC2571
SYNC
U1 Micrel MIC2571-2BM
C1 Sprague 594D476X0016C2T Tantalum ESR = 0.11Ω
C2 Sprague 594D156X0025C2T Tantalum ESR = 0.22Ω
C3 Sprague 594D156X0025C2T Tantalum ESR = 0.22Ω
D1 Motorola MBR0530T1
D2 Motorola MBR0530T1
L1 Coilcraft DO1608C-154 DCR = 1.7Ω
7
6
1
2
8
IN
C2
0.1µF
C1
47µF
16V
D3
1N4148
L1
150µH
R2
1.1M
1.1%
R1
20k
1%
1V to 1.5V
1 Cell
R3
220k C2
15µF
25V –V
OUT
–12V/2mA
D2
MBR0530
D1
MBR0530
C1
15µF
25V
–V
OUT
= – 0.22V (1+R2/R1) + 0.6V
Example 6. –12V/2mA Regulator
1997 11 MIC2571
MIC2571 Micrel
Suggested Manufacturers List
Inductors Capacitors Diodes
Coilcraft AVX Corp. General Instruments (GI)
1102 Silver Lake Rd. 801 17th Ave. South 10 Melville Park Rd.
Cary, IL 60013 Myrtle Beach, SC 29577 Melville, NY 11747
PH (708) 639-2361 PH (803) 448-9411 PH (516) 847-3222
FX (708) 639-1469 FX (803) 448-1943 FX (516) 847-3150
Coiltronics Sanyo Video Components Corp. International Rectifier Corp.
6000 Park of Commerce Blvd. 2001 Sanyo Ave. 233 Kansas St.
Boca Raton, FL 33487 San Diego, CA 92173 El Segundo, CA 90245
PH (407) 241-7876 PH (619) 661-6835 PH (310) 322-3331
FX (407) 241-9339 FX (619) 661-1055 FX (310) 322-3332
Sumida Sprague Electric Motorola Inc.
637 E. Golf Road, Suite 209 Lower Main Street 3102 North 56th St.
Arlington Heights, IL 60005Sanford, ME 04073 MS 56-126
PH (708) 956-0666 PH (207) 324-4140 Phoenix, AZ 85018
FX (708) 956-0702 PH (602) 244-3576
FX (602) 244-4015
Component Side and Silk Screen (Not Actual Size)
Solder Side and Silk Screen (Not Actual Size)
Evaluation Board Layout
MIC2571 Micrel
MIC2571 12 1997
Package Information
0.008 (0.20)
0.004 (0.10) 0.039 (0.99)
0.035 (0.89)
0.021 (0.53)
0.012 (0.03) R
0.0256 (0.65) TYP
0.012 (0.30) R
5° MAX
0° MIN
0.122 (3.10)
0.112 (2.84)
0.120 (3.05)
0.116 (2.95)
0.012 (0.03)
0.007 (0.18)
0.005 (0.13)
0.043 (1.09)
0.038 (0.97)
0.036 (0.90)
0.032 (0.81)
DIMENSIONS:
INCH (MM)
0.199 (5.05)
0.187 (4.74)
8-Pin MSOP (MM)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 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.
© 1997 Micrel Incorporated
