MIC2571
Micrel
MIC2571
Single-Cell Switching Regulator
Final Information
General Description
Features
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.
• 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
The MIC2571 is available in selectable fixed output or adjustable 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 configured 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, inductor, input capacitor and output capacitor) to implement a
boost regulator. A complete regulator can be constructed in
a 0.3 in2 area.
Applications
•
•
•
•
•
•
•
Pagers
LCD bias generator
Battery-powered, hand-held instruments
Palmtop computers
Remote controls
Detectors
Battery Backup Supplies
All versions are available in an 8-lead MSOP with an operating range from –40°C to +85°.
Typical Applications
D1
MBR0530
L1
150µH
D1
MBR0530
L1
150µH
5V/5mA
3.3V/8mA
8
8
IN
1V to1.5V
1 Cell
C1*
47µF
16V
MIC2571-1
SW
1
2.85V
6
3.3V
5
5V
SYNC
7
4
GND
2
IN
1V to1.5V
1 Cell
C1*
47µF
16V
MIC2571-1
SW
1
2.85V
6
3.3V
5
5V
C2
47µF
16V
SYNC
7
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in2 excluding C1
4
GND
2
C2
47µF
16V
* Needed if battery is ≥ 4" from MIC2571
Circuit size < 0.3 in2 excluding C1
Single-Cell to 5V DC-to-DC Converter
Single-Cell to 3.3V DC-to-DC Converter
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
1997
1
MIC2571
MIC2571
Micrel
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
MIC2571-1
MIC2571-2
SW
1
8
IN
SYNC
GND
2
7
SYNC
6
2.85V
NC
3
6
FB
5
3.3V
NC
4
5
NC
SW
1
8
IN
GND
2
7
NC
3
5V
4
Adjustable Voltage
20kHz Frequency
Selectable Voltage
20kHz Frequency
8-Lead MSOP (MM)
Pin Description
†
Pin No. (Version†)
Pin Name
1
SW
2
GND
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
5 (-2)
NC
6 (-1)
2.85V
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
Pin Function
Switch: NPN output switch transistor collector.
Power Ground: NPN output switch transistor emitter.
3.3V Feedback (Input): Fixed 3.3V feedback to internal resistive divider.
Not internally connected.
2.85V Feedback (Input): Fixed 2.85V feedback to internal resistive divider.
Supply (Input): Positive supply voltage input.
Example: (-1) indicates the pin description is applicable to the MIC2571-1 only.
MIC2571
2
1997
MIC2571
Micrel
Absolute Maximum Ratings
Operating 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
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
Electrical Characteristics
VIN = 1.5V; TA = 25°C, bold indicates –40°C ≤ TA ≤ 85°C; unless noted
Parameter
Condition
Min
Typ
Input Voltage
Startup guaranteed, ISW = 100mA
Quiescent Current
Output switch off
Fixed Feedback Voltage
MIC2571-1; V2.85V pin = VOUT, ISW = 100mA
MIC2571-1; V3.3V pin = VOUT, ISW = 100mA
MIC2571-1; V5V pin = VOUT, ISW = 100mA
2.7
3.14
4.75
2.85
3.30
5.00
3.0
3.47
5.25
V
V
V
Reference Voltage
MIC2571-2, [adj. voltage versions], ISW = 100mA, Note 1
208
220
232
mV
Comparator Hysteresis
MIC2571-2, [adj. voltage versions]
Output Hysteresis
0.9
Max
Units
15
V
V
µA
120
6
mV
MIC2571-1; V2.85V pin = VOUT, ISW = 100mA
MIC2571-1; V3.3V pin = VOUT, ISW = 100mA
MIC2571-1; V5V pin = VOUT, ISW = 100mA
65
75
120
mV
mV
mV
Feedback Current
MIC2571-1; V2.85V pin = VOUT
MIC2571-1; V3.3V pin = VOUT
MIC2571-1; V5V pin = VOUT
MIC2571-2, [adj. voltage versions]; VFB = 0V
4.5
4.5
4.5
25
µA
µA
µA
nA
Reference Line Regulation
1.0V ≤ VIN ≤ 12V
0.35
%/V
Switch Saturation Voltage
VIN = 1.0V, ISW = 200mA
VIN = 1.2V, ISW = 600mA
VIN = 1.5V, ISW = 800mA
200
400
500
mV
mV
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
67
%
Duty Cycle
VFB < VREF, ISW = 100mA
General Note: Devices are ESD protected; however, handling precautions are recommended.
Note 1:
1997
Measured using comparator trip point.
3
MIC2571
MIC2571
Micrel
Typical Characteristics
Switch Saturation Voltage
Switch Saturation Voltage
1.0
SWITCH CURRENT (A)
SWITCH CURRENT (A)
0.8
1.4V
0.6
1.3V
0.4
1.2V
1.1V
0.2
Switch Saturation Voltage
1.0
1.4V
TA = –40°C
0.8
1.2V
TA = 25°C
0.6
1.1V
0.4
1.0V
0.2
VIN = 0.9V
1.3V
1.4V
1.3V
SWITCH CURRENT (A)
1.0
1.2V
TA = 85°C
0.8
1.1V
0.6
1.0V
0.4
VIN = 0.9V
0.2
VIN = 1.0V
0
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
0
1.0
Oscillator Frequency
vs. Temperature
0
1.0
0
25
20
70
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
1.0
Quiescent Current
vs. Temperature
75
VIN = 1.5V
ISW = 100mA
DUTY CYCLE (%)
200
VIN = 1.5V
ISW = 100mA
65
60
55
VIN = 1.5V
175
150
125
100
75
15
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
50
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
50
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
Feedback Current
vs. Temperature
Feedback Current
vs. Temperature
Quiescent Current
vs. Supply Voltage
VIN = 1.5V
MIC2571-1
6
4
2
Output Current Limit
vs. Temperature
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
MIC2571
VIN = 2.5V
MIC2571-2
30
20
10
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
SWITCH LEAKAGE CURRENT (nA)
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
40
200
QUIESCENT CURRENT (µA)
8
50
FEEDBACK CURRENT (nA)
FEEDBACK CURRENT (µA)
10
–40°C
175
+25°C
150
125
+85°C
100
75
50
25
0
Switch Leakage Current
vs. Temperature
0
2
4
6
8
SUPPLY VOLTAGE (V)
10
Output Hysteresis
vs. Temperature
1000
150
OUTPUT HYSTERESIS (mV)
OSC. FREQUENCY (kHz)
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
Oscillator Duty Cycle
vs. Temperature
30
CURRENT LIMIT (A)
0
QUIESCENT CURRENT (µA)
0
100
10
1
0.1
0.01
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
4
125
5V
100
3.3V
75
50
VOUT = 2.85V
25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
1997
MIC2571
Micrel
Block Diagrams
VBATT
VOUT
IN
SYNC
MIC2571-1
Oscillator
0.22V
Reference
5V
3.3V
Driver
SW
2.85V
GND
Selectable Voltage Version with External Components
VBATT
VOUT
IN
SYNC
MIC2571-2
Oscillator
0.22V
Reference
Driver
FB
SW
GND
Adjustable Voltage Version with External Components
1997
5
MIC2571
MIC2571
Micrel
Supply
Voltage
5V
IPEAK
Output
Voltage
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.
Peak
Current
Functional Description
VIN
0V
0mA
5V
Time
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 comparator 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.
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 frequency. 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 combinations 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:
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 approximately 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.
duty cycle ≤
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.
VOUT + VDIODE – VIN
VOUT + VDIODE – VSAT
Inductor Current
Current "ratchet"
without current limit
Current limit threshold
Continuous current
Discontinuous current
Time
Figure 2. Current Limit Behavior
MIC2571
6
1997
MIC2571
Micrel
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 electrolytic capacitors usually are the worst choice while tantalum
capacitors are typically better. Figure 4 demonstrates the
effect of capacitor ESR on output ripple voltage.
Figure 2 shows an example of inductor current in the continuous 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 conditions.
Inductors, Capacitors and Diodes
The importance of choosing correct inductors, capacitors and
diodes can not be ignored. Poor choices for these components can cause problems as severe as circuit failure or as
subtle as poorer than expected efficiency.
OUTPUT VOLTAGE (V)
5.25
Inductor Current
a.
b.
5.00
c.
4.75
Time
Figure 3. Inductor Current: a. Normal,
b. Saturating and c. Excessive ESR
0
500
1000
TIME (µs)
1500
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 rectification 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:
Inductors
Inductors must be selected such that they do not saturate
under maximum current conditions. When an inductor saturates, 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 significantly 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 backwards 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.
I =
V
× t
L
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:
V1 = VIN – VSAT
1997
7
MIC2571
MIC2571
Micrel
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:
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
× t1
I
V2 = VOUT + VDIODE – VIN
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:
L =
× t1
duty cycle
fOSC
To illustrate the use of these equations a design example will
be given:
V1
t
= 2
V2
t1
Assume:
MIC2571-1 (fixed oscillator)
VOUT = 5V
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.
MIC2571
2 × Average IIN(max)
where t1 =
V1 × t1 = V2 × t 2
Average IIN(max) =
VIN(min)
IOUT(max) =5mA
VIN(min) = 1.0V
efficiency = 75%.
Average IIN(max) =
5V × 5mA
= 33.3mA
1.0V × 0.75
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).
L =
VOUT × IOUT(max)
VIN(min) × Efficiency
8
1997
MIC2571
Micrel
Application Examples
L1
D1
150µH
MBR0530
VOUT
5V/5mA
8
IN
C1*
47µF
16V
1V to 1.5V
1 Cell
1
SW
MIC2571
5V
4
SYNC GND
7
C2
47µF
16V
2
* Needed if battery is more than 4" away from MIC2571
U1
C1
C2
D1
L1
Micrel
Sprague
Sprague
Motorola
Coilcraft
MIC2571-1BMM
594D476X0016C2T Tantalum ESR = 0.11Ω
594D476X0016C2T Tantalum ESR = 0.11Ω
MBR0530T1
DO1608C-154 DCR = 1.7Ω
Example 1. 5V/5mA Regulator
L1
D1
150µH
MBR0530
VOUT
3.3V/8mA
8
1
IN
C1*
47µF
16V
1V to 1.5V
1 Cell
SW
MIC2571
3.3V
SYNC GND
7
5
C2
47µF
16V
2
* Needed if battery is more than 4" away from MIC2571
U1
C1
C2
D1
L1
Micrel
Sprague
Sprague
Motorola
Coilcraft
MIC2571-1BMM
594D476X0016C2T Tantalum ESR = 0.11Ω
594D476X0016C2T Tantalum ESR = 0.11Ω
MBR0530T1
DO1608C-154 DCR = 1.7Ω
Example 2. 3.3V/8mA Regulator
L1
D1
150µH
MBR0530
VOUT
12V/2mA
8
IN
1.0V to 1.5V
1 Cell
C1*
47µF
16V
SW
1
R2
1M
1%
MIC2571
FB
6
SYNC GND
7
2
C2
15µF
25V
R1
20k
1%
* Needed if battery is more than 4" away from MIC2571
VOUT = 0.22V
U1
C1
C2
D1
L1
Micrel
Sprague
Sprague
Motorola
Coilcraft
(1 + R2/R1)
MIC2570-2BMM
594D476X0016C2T Tantalum ESR = 0.11Ω
594D156X0025C2T Tantalum ESR = 0.22Ω
MBRA0530T1
DO1608C-154 DCR = 1.7Ω
Example 3. 12V/40mA Regulator
1997
9
MIC2571
MIC2571
Micrel
L1
D1
150µH
C3
47µF
16V
8
IN
C1*
47µF
16V
1V to 1.5V
1 Cell
SW
1
MIC2571
5V
SYNC
GND
7
2
C2
47µF
16V
4
D2
MBR0530
* Needed if battery is more than 4" away from MIC2571
D3
MBR0530
U1
C1
C2
C3
C4
D1
D2
D3
L1
Micrel
Sprague
Sprague
Sprague
Sprague
Motorola
Motorola
Motorola
Coilcraft
VOUT/+IOUT
5V/2mA
MBR0530
C4
47µF
16V
R1
220k
MIC2571-1BMM
594D476X0016C2T Tantalum ESR = 0.11Ω
594D476X0016C2T Tantalum ESR = 0.11Ω
594D476X0016C2T Tantalum ESR = 0.11Ω
594D476X0016C2T Tantalum ESR = 0.11Ω
MBR0530T1
MBR0530T1
MBR0530T1
DO1608C-154 DCR = 1.7Ω
–VOUT/–IOUT
–5V/2mA
–IOUT ≤ +IOUT
Example 4. ±5V/2mA Regulator
L1
D1
47µH
1V to 1.5V
1 Cell
MBRA140
Q1
2N3906
C1
100µF
10V
VOUT
5V/15mA
8
R1
51k
IN
1
SW
MIC2571
5V
4
SYNC GND
7
C2
100µF
10V
2
Minimum Start-Up Supply Voltage
VIN = 1V, ILOAD = 0A
VIN = 1.2V, ILOAD = 15mA
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
Example 5. 5V/15mA Regulator
L1
1V to 1.5V
1 Cell
D3
150µH
1N4148
8
IN
C1
47µF
16V
SW
C1
15µF
25V
1
R2
1.1M
1.1%
MIC2571
FB
6
C2
0.1µF
SYNC GND
7
R1
20k
1%
2
D1
MBR0530
–VOUT = – 0.22V
U1
C1
C2
C3
D1
D2
L1
Micrel
Sprague
Sprague
Sprague
Motorola
Motorola
Coilcraft
(1+R2/R1) + 0.6V
D2
MBR0530
MIC2571-2BM
594D476X0016C2T Tantalum ESR = 0.11Ω
594D156X0025C2T Tantalum ESR = 0.22Ω
594D156X0025C2T Tantalum ESR = 0.22Ω
MBR0530T1
MBR0530T1
DO1608C-154 DCR = 1.7Ω
R3
220k
C2
15µF
25V
–VOUT
–12V/2mA
Example 6. –12V/2mA Regulator
MIC2571
10
1997
MIC2571
Micrel
Suggested Manufacturers List
Inductors
Capacitors
Diodes
Coilcraft
1102 Silver Lake Rd.
Cary, IL 60013
PH (708) 639-2361
FX (708) 639-1469
AVX Corp.
801 17th Ave. South
Myrtle Beach, SC 29577
PH (803) 448-9411
FX (803) 448-1943
General Instruments (GI)
10 Melville Park Rd.
Melville, NY 11747
PH (516) 847-3222
FX (516) 847-3150
Coiltronics
6000 Park of Commerce Blvd.
Boca Raton, FL 33487
PH (407) 241-7876
FX (407) 241-9339
Sanyo Video Components Corp.
2001 Sanyo Ave.
San Diego, CA 92173
PH (619) 661-6835
FX (619) 661-1055
International Rectifier Corp.
233 Kansas St.
El Segundo, CA 90245
PH (310) 322-3331
FX (310) 322-3332
Sprague Electric
Motorola Inc.
3102 North 56th St.
MS 56-126
Phoenix, AZ 85018
PH (602) 244-3576
FX (602) 244-4015
Sumida
637 E. Golf Road, Suite 209
Arlington Heights, IL
PH (708) 956-0666
FX (708) 956-0702
Lower Main Street
60005Sanford, ME 04073
PH (207) 324-4140
Evaluation Board Layout
Component Side and Silk Screen (Not Actual Size)
Solder Side and Silk Screen (Not Actual Size)
1997
11
MIC2571
MIC2571
Micrel
Package Information
0.199 (5.05)
0.187 (4.74)
0.122 (3.10)
0.112 (2.84)
DIMENSIONS:
INCH (MM)
0.120 (3.05)
0.116 (2.95)
0.036 (0.90)
0.032 (0.81)
0.043 (1.09)
0.038 (0.97)
0.012 (0.30) R
0.012 (0.03)
0.0256 (0.65) TYP
0.008 (0.20)
0.004 (0.10)
5° MAX
0° MIN
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)
8-Pin MSOP (MM)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
USA
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
MIC2571
12
1997
工商网监
湘ICP备2023018690号
