MIC MIC2570-1YM

MIC2570
Micrel, Inc.
MIC2570
Two-Cell Switching Regulator
General Description
Features
Micrel’s MIC2570 is a micropower boost switching regulator
that operates from two alkaline, two nickel-metal-hydride
cells, or one lithium cell.
• Operates from a two-cell supply
1.3V to 15V operation
• 130µA typical quiescent current
• Complete regulator fits 0.6 in2 area
• 2.85V/3.3V/5V selectable output voltage (MIC2570-1)
• Adjustable output up to 36V (MIC2570-2)
• 1A current limited pass element
• Frequency synchronization input
• 8-lead SOIC package
The MIC2570 accepts a positive input voltage between 1.3V
and 15V. Its typical no-load supply current is 130µA.
The MIC2570 is available in selectable fixed output or adjustable output versions. The MIC2570-1 can be configured
for 2.85V, 3.3V, or 5V by connecting one of three separate
feedback pins to the output. The MIC2570-2 can be configured for an output voltage ranging between its input voltage
and 36V, using an external resistor network.
Applications
The MIC2570 has a fixed switching frequency of 20kHz. An
external SYNC connection allows the switching frequency to
be synchronized to an external signal.
•
•
•
•
•
•
•
•
•
•
The MIC2570 requires only four components (diode, inductor,
input capacitor and output capacitor) to implement a boost
regulator. A complete regulator can be constructed in a 0.6
in2 area.
All versions are available in an 8-lead SOIC with an operating
range from –40°C to +85°.
LCD bias generator
Glucose meters
Single-cell lithium to 3.3V or 5V converters
Two-cell alkaline to ±5V converters
Two-cell alkaline to –5V converters
Battery-powered, hand-held instruments
Palmtop computers
Remote controls
Detectors
Battery Backup Supplies
Typical Applications
L1
47µH
D1
MBRA140
5V/100mA
1
L1
50µH
2
3
8
2.0V–3.1V
2 AA Cells
C1
100µF
10V
IN
MIC2570-1 S W
2.85V
3.3V
SYNC
7
C2
100µF
10V MBRA140
5V
GND
2
1
C1
2.5V to 4.2V 100µF
1 Li Cell
10V
6
5
4
U1
8
IN
SW
MIC2570
3.3V
S Y N C GND
C2
220µF
10V
7
Two-Cell to 5V DC-to-DC Converter
D1
L1
2
1
VOU T
3.3V/80mA
4
5
C3
330µF
6.3V
Single-Cell Lithium to 3.3V/80mARegulator
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2007
1
MIC2570
MIC2570
Micrel, Inc.
Ordering Information
Part Number
Temperature
Range
Voltage
Frequency
Package
Standard
Pb-Free
MIC2570-1BM
MIC2570-1YM
–40ºC to +85ºC
Selectable*
20kHz
8-pin SOIC
MIC2570-2BM
MIC2570-2YM
–40ºC to +85ºC
Adjustable
20kHz
8-pin SOIC
* Externally selectable for 2.85V, 3.3V, or 5V
Pin Configuration
MIC2570-2
MIC2570-1
SW 1
8 IN
GND 2
7 SYNC
SW 1
8
IN
GND 2
7
SYNC
NC 3
6 2.85V
NC 3
6
FB
5V 4
5 3.3V
NC 4
5
NC
Adjustable Voltage
20kHz Frequency
Selectable Voltage
20kHz Frequency
8-Lead SOIC (M)
Pin Description
Pin No. (Version†)
†
Pin Name
Pin Function
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
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.
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 MIC2570-1 only.
MIC2570
2
August 2007
MIC2570
Micrel, Inc.
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
SOIC Power Dissipation (PD) .................................. 400mW
Supply Voltage (VIN) ..................................... +1.3V to +15V
Ambient Operating Temperature (TA) ......... –40°C to +85°C
Junction Temperature (TJ) ........................ –40°C to +125°C
SOIC Thermal Resistance (θJA) ............................ 140°C/W
Electrical Characteristics
VIN = 2.5V; TA = 25°C, bold indicates –40°C ≤ TA ≤ 85°C; unless noted
Parameter
Condition
Min
Input Voltage
Startup guaranteed, ISW = 100mA
1.3
MIC2570-1; V2.85V pin = VOUT, ISW = 100mA
MIC2570-1; V3.3V pin = VOUT, ISW = 100mA
MIC2570-1; 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
208
220
232
mV
Quiescent Current
Fixed Feedback Voltage
Reference Voltage
Comparator Hysteresis
Output Hysteresis
Feedback Current
Reference Line Regulation
Switch Saturation Voltage
Switch Leakage Current
Oscillator Frequency
Maximum Output Voltage
Output switch off
MIC2570-2, [adj. voltage versions], ISW = 100mA, Note 1
MIC2570-2, [adj. voltage versions]
Typ
Max
Units
15
V
130
µA
6
mV
MIC2570-1; V2.85V pin = VOUT, ISW = 100mA
MIC2570-1; V3.3V pin = VOUT, ISW = 100mA
MIC2570-1; V5V pin = VOUT, ISW = 100mA
65
75
120
mV
mV
mV
6
6
6
25
µA
µA
µA
nA
1.5V ≤ VIN ≤ 15V
0.35
%/V
VIN = 1.3V, ISW = 300mA
VIN = 1.5V, ISW = 800mA
VIN = 3.0V, ISW = 800mA
250
450
450
mV
mV
mV
1
µA
MIC2570-1, -2; ISW = 100mA
20
kHz
MIC2570-1; V2.85V pin = VOUT
MIC2570-1; V3.3V pin = VOUT
MIC2570-1; V5V pin = VOUT
MIC2570-2 [adj. voltage versions]; VFB = 0V
Output switch off, VSW = 36V
36
Sync Threshold Voltage
V
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:
Measured using comparator trip point.
August 2007
3
MIC2570
MIC2570
Micrel, Inc.
Typical Characteristics
1.0
VIN= 3.0V
0.5
0
30
1.5V
0
2.5V
2.0V
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
1.5
0
75
70
0
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
6
Oscillator Duty Cycle
vs. Temperature
VIN = 2.5V
IS W = 100mA
50
40
20
2
10
Output Current Limit
vs. Temperature
CURRENT LIMIT (A)
1.50
1.25
1.00
0.75
0.50
0.25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
1000
10
1
0.1
0.01
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
4
1.0
Quiescent Current
vs. Temperature
VIN = 2.5V
175
150
125
100
75
Quiescent Current
vs. Supply Voltage
200
–40°C
175
+25°C
150
125
+85°C
100
75
50
25
0
Switch Leakage Current
vs. Temperature
100
0.2
0.4
0.6
0.8
SWITCH VOLTAGE (V)
50
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
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)
1.75
VIN = 2.5V
MIC2570-2
0
200
Feedback Current
vs. Temperature
30
4
0
1.0
150
OUTPUT HYSTERESIS (mV)
8
VIN = 2.5V
MIC2570-1
1.5V
0.5
50
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
FEEDBACK CURRENT (nA)
10
FEEDBACK CURRENT (µA)
1.5V
55
Feedback Current
vs. Temperature
VIN = 3.0V
1.0
60
15
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
MIC2570
2.0V
65
20
TA = 85°C
1.5
VIN = 3.0V
0.5
Oscillator Frequency
vs. Temperature
25
2.5V
1.0
1.0
VIN = 2.5V
IS W = 100mA
OSC. FREQUENCY (kHz)
TA = 25°C
Switch Saturation Voltage
2.0
QUIESCENT CURRENT (µA)
1.5
Switch Saturation Voltage
SWITCH CURRENT (A)
SWITCH CURRENT (A)
TA = –40°C
2.0
QUIESCENT CURRENT (µA)
Switch Saturation Voltage
DUTY CYCLE (%)
SWITCH CURRENT (A)
2.0
125
100
0
2
4
6
8
SUPPLY VOLTAGE (V)
10
Output Hysteresis
vs. Temperature
5V
3.3V
75
50
2.85V
25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
August 2007
MIC2570
Micrel, Inc.
Block Diagrams
VBATT
VOU T
IN
SYNC
MIC2570-1
Oscillator
0.22V
Reference
5V
Driver
SW
3.3V 2.85V
GND
Selectable Voltage Version with External Components
VOU T
VBATT
SYNC
IN
MIC2570-2
Oscillator
0.22V
Reference
Driver
FB
SW
GND
Adjustable Voltage Version with External Components
August 2007
5
MIC2570
MIC2570
Micrel, Inc.
Functional Description
Output
Voltage
Inductor
Current
Supply
Voltage
The MIC2570 switch-mode power supply (SMPS) is a gated
oscillator architecture designed to operate from an input
voltage as low as 1.3V 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.
5V
VIN
0V
IPEAK
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.
Figure 1. Typical Boost Regulator Waveforms
Synchronization
The SYNC pin is used to synchronize the MIC2570 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.
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.
Current Limit
Current limit for the MIC2570 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:
VOUT + V DIODE – V IN
duty cycle ≤
VOUT + V DIODE – V SAT
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.
Output Waveforms
Current “ratchet”
without current limit
Current Limit
Threshold
Inductor Current
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.
Continuous
Current
Discontinuous
Current
Time
Figure 2. Current Limit Behavior
MIC2570
6
August 2007
MIC2570
Micrel, Inc.
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.
capacitors are typically better. Figure 4 demonstrates the
effect of capacitor ESR on output ripple voltage.
OUTPUT VOLTAGE (V)
5.25
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.
4.75
Inductor Current
a.
0
500
1000
TIME (µs)
1500
Figure 4. Output Ripple
b.
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.
c.
Time
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.
Figure 3. Inductor Current: a. Normal,
b. Saturating, and c. Excessive ESR
Inductor Behavior
Inductors
The inductor is an energy storage and transfer device. Its
behavior (neglecting series resistance) is described by the
following equation:
V
×t
I=
L
where:
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.
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 = V IN – V SAT
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.
Capacitors
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:
V2 = V OUT + V DIODE – V IN
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
August 2007
5.00
For normal operation the inductor current is a triangular
waveform which returns to zero current (discontinuous mode)
7
MIC2570
MIC2570
Micrel, Inc.
at each cycle. At the threshold between continuous and discontinuous operation we can use the fact that I1 = I2 to get:
V1 × t 1 = V 2 × t 2
V1
V2
=
L=
L=
t2
t1
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).
I
× t1
VIN(min)
2 × Average I IN(max)
where t 1 =
× t1
duty cycle
fOSC
To illustrate the use of these equations a design example
will be given:
Assume:
MIC2570-1 (fixed oscillator)
VOUT = 5V
IOUT(max) =50mA
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.
VOUT × I OUT(max)
Average I IN(max) =
VIN(min) × Efficiency
VIN(min) = 1.8V
efficiency = 75%.
Average I IN(max) =
L=
5V × 50mA
1.8V × 0.75
× 185.2mA
1.8V × 0.7
2 × 185.2mA × 20kHz
L = 170µH
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:
MIC2570
V
Use the next lowest standard value of inductor and verify
that it does not saturate at a current below about 400mA
(< 2 × 185.2mA).
8
August 2007
MIC2570
Micrel, Inc.
Application Examples
MBRA140
L1
47µH
U1
C1
2.0V to 3.1V 100µF
2 Cells
10V
SW
MIC2570
GND
SYNC
Micrel
AVX
AVX
Motorola
Coilcraft
5V
47µH
1
C1
2.0V to 3.1V 100µF
2 Cells
10V
U1
C2
220µF
10V
U1
C1
C2
D1
L1
IN
MIC2570
SYNC
7
U1
C1
C2
D1
L1
Micrel
AVX
AVX
Motorola
Coilcraft
SW
FB
GND
1
R2
1M
1%
Micrel
AVX
AVX
AVX
Motorola
Coiltronics
MBRA140
47µH
4
5
2
C3
330µF
6.3V
MIC2570-1BM
TPSD107M010R0100 Tantalum, ESR = 0.1Ω
TPSD107M010R0100 Tantalum, ESR = 0.1Ω
TPSE337M006R0100 Tantalum, ESR = 0.1Ω
MBRA140T3
CTX50-4P DCR = 0.097Ω
SW
S Y N C GND
FB
U2
6V
3
2
D1
8
IN
MIC2570
Micrel
Micrel
AVX
AVX
Sprague
Motorola
Coilcraft
1
Example 4. Single Cell Lithium
to 3.3V/80mA Regulator
L1
7
SW
3.3V
S Y N C GND
U1
C1
C2
C3
D1
L1
D1
VOU T
3.3V/80mA
L1
IN
7
U1
2
C2
100µF
10V MBRA140
8
MIC2570
R1
18.7k
1%
Example 3. 12V/40mA Regulator
U1
U2
C1
C2
C3
D1
L1
U1
C1
2.5V to 4.2V 100µF
1 Li Cell
10V
C2
33µF
25V
L1
50µH
3
VOU T = 0.22V × (1+R2/R1)
MIC2570-2BM
TPSD107M010R0100 Tantalum, ESR = 0.11Ω
TPSE336M025R0300 Tantalum, ESR = 0.3Ω
MBRA140T3
DO3316P-473, DCR = 0.12Ω
C1
2.0V to 3.1V 100µF
2 Cells
10V
C2
330µF
6.3V
MIC2570-1BM
TPSD107M010R0100 Tantalum, ESR = 0.1Ω
TPSE337M006R0100 Tantalum, ESR = 0.1Ω
MBRA140T3
DO3316P-473, DCR = 0.12Ω
VOU T
12V/40mA
6
2
5
Example 2. 3.3V/150mA Regulator
D1
1
Micrel
AVX
AVX
Motorola
Coilcraft
1
2
7
MBRA140
8
MIC2570
3.3V
S Y N C GND
Example 1. 5V/100mA Regulator
47µH
SW
VOU T
3.3V/150mA
D1
8
IN
4
MIC2570-1BM
TPSD107M010R0100 Tantalum, ESR = 0.1Ω
TPSE227M010R0100 Tantalum, ESR = 0.1Ω
MBRA140T3
DO3316P-473, DCR = 0.12Ω
L1
U1
C1
2.0V to 3.1V 100µF
2 Cells
10V
2
7
U1
C1
C2
D1
L1
D1
8
IN
MBRA140
L1
VOU T
5V/100mA
R2
523k
1%
1
6
R1
20k
1%
2
IN
EN
OUT
MIC5203
GND
1
C2
220µF
10V
4
VOU T
5V/80mA
C3
1µF
16V
VOU T = 0.22V × (1+R2/R1)
MIC2570-2BM
MIC5203-5.0BM4
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0300 Tantalum ESR = 0.1Ω
293D105X0016A2W Tantalum
MBRA140T3
DO3316P-473 DCR = 0.12Ω
Example 5. Low-Noise 5V/80mA Regulator
August 2007
9
MIC2570
MIC2570
Micrel, Inc.
47µH
C1
2.0V to 3.1V 100µF
2 Cells
10V
U1
SW
MIC2570
S Y N C GND
U1
U2
C1
C2
C3
D1
L1
Micrel
Micrel
AVX
AVX
Sprague
Motorola
Coilcraft
3
2
R2
374k
1%
1
FB
IN
EN
OUT
MIC5203
R1
20k
1%
VOU T
3.3V/80mA
4
GND
1
C2
220µF
10V
6
2
7
4.3V
D1
8
IN
U2
MBRA140
L1
C3
1µF
16V
VOU T = 0.22V × (1+R2/R1)
MIC2570-2BM
MIC5203-3.3BM4
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0100 Tantalum ESR = 0.1Ω
293D105X0016A2W Tantalum
MBRA140T3
DO3316P-473 DCR = 0.12Ω
Example 6. Low-Noise 3.3V/80mA Regulator
MBRA140
L1
47µH
C1
2.0V to 3.1V 100µF
2 Cells
16V
U1
SW
MIC2570
S Y N C GND
2
7
U1
C1
C2
C3
C4
D1
D2
D3
L1
Micrel
AVX
AVX
AVX
AVX
Motorola
Motorola
Motorola
Coilcraft
D1
8
IN
MIC2570-1BM
TPSD107M010R0100
TPSE227M010R0100
TPSE227M010R0100
TPSE227M010R0100
MBRA140T3
MBRA140T3
MBRA140T3
DO3316P-473, DCR =
5V
C3
220µF
10V
1
+VOU T
5V/50mA
– IOU T≤ +IOU T
4
C2
220µF
10V
D2
MBRA140
Tantalum,
Tantalum,
Tantalum,
Tantalum,
ESR
ESR
ESR
ESR
=
=
=
=
0.1Ω
0.1Ω
0.1Ω
0.1Ω
C4
220µF
10V
D3
MBRA140
–VOU T
–4.5V to –5V/50mA
1.2Ω
Example 7. ±5V/50mA Regulator
47µH
U1
MIC2570
SW
FB
S Y N C GND
7
2
1
Micrel
AVX
AVX
AVX
Motorola
Motorola
Coilcraft
R2
549k
1%
6
D1
MBRA140
C3
0.1µF
R1
4.99k
1%
C2
22µF
35V
–VOU T
MIC2570-2BM
–24V/20mA
TPSD107M010R0100, Tantalum ESR = 0.1Ω
TPSE226M035R0300, Tantalum ESR = 0.3Ω
TPSE226M035R0300, Tantalum ESR = 0.3Ω
MBRA140T3
MBRA140T3
DO3316P-473, DCR = 0.12Ω
–VOU T = –0.22V × (1+R2/R1) + 0.6V
U1
C1
C2
C3
D1
D2
L1
1N4148
C1
22µF
35V
8
IN
C1
100µF
10V
D3
L1
2.0V to 3.1V
2 Cells
D2
MBRA140
R3
220k
Example 8. –24V/20mA Regulator
MIC2570
10
August 2007
MIC2570
Micrel, Inc.
C2
68µF, 35V
L1
47µH
U1
C1
2.0V to 3.1V 330µF
2 Cell
16V
8
IN
MIC2570
U1
C1
C2
C3
C4
D1
D2
D3
L1
Micrel
Sanyo
Sanyo
Sanyo
Sanyo
Motorola
Motorola
Motorola
Sumida
D2
D3
1N5819
1N5819
1N5819
C3
68µF
35V
1
SW
VOU T
50V/10mA
R2
2.2M
1%
6
FB
S Y N C GND
7
D1
C4
82µF
63V
R1
10k
1%
2
VOU T = 0.22 ×(1+R2/R1)
MIC2570-2BM
16MV330GX Electrolytic ESR = 0.1Ω
35MV68GX
Electrolytic ESR = 0.22Ω
35MV68GX
Electrolytic ESR = 0.22Ω
63MV826X Electrolytic ESR = 0.34Ω
1N5819
1N5819
1N5819
RCH106-470k DCR = 0.16Ω
Example 9. Voltage Doubler
D1
MBRA140
L1
U1
C1
2.0V to 3.1V 100µF
2 Cell
10V
47µH
8
IN
SW
MIC2570
FB
S Y N C GND
D2
LED
X5 IL E D
6
C2
220µF
10V
R1
11k
1%
2
7
U1
C1
C2
D1
L1
1
I = 0.22V/R1
MIC2570-2BM
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0100 Tantalum ESR = 0.1Ω
MBRA140T3
DO3316P-473 DCR = 0.12Ω
Micrel
AVX
AVX
Motorola
Coilcraft
Example 10. Constant-Current LED Supply
L1
D1
47µH
C1
2.0V to 3.1V 100µF
2 Cell
10V
U1
MBRA140
8
IN
MIC2570
7
2
R2
434k
1%
1
SW
FB
S Y N C GND
6
74C04
Enable
Shutdown
Micrel
AVX
AVX
Motorola
Coilcraft
C2
220µF
10V
R1
20k
1%
D2
1N4148
VOU T = 0.22V × (1+R2/R1)
U1
C1
C2
D1
L1
VOU T
5V/100mA
R3
100k
MIC2570-2BM
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0100 Tantalum ESR = 0.1Ω
MBRA140T3
DO3316P-473 DCR = 0.12Ω
Example 11. 5V/100mA Regulator with Shutdown
August 2007
11
MIC2570
MIC2570
Micrel, Inc.
R1
510Ω
L1
47µH
U1
C1
2.0V to 3.1V 100µF
2 Cell
10V
MIC2570
SW
R2
434k
1%
1
6
FB
S Y N C GND
D2
7
2
1N4148
U1
C1
C2
C3
D1
L1
Q1
Micrel
AVX
AVX
AVX
Motorola
Coilcraft
Zetex
MIC2570-2BM
TPSD107M010R0100
TPSE227M010R0100
TPSE227M010R0100
MBRA140T3
DO3316P-473 DCR =
ZTX7888
C3
220µF
10V
R3
100k
74C04
Enable
Shutdown
C2
220µF
10V
R1
20k
1%
VOU T = 0.22V × (1+R2/R1)
VOU T
5V/100mA
Q1
ZTX7888
MBRA140
8
IN
D1
Tantalum ESR = 0.1Ω
Tantalum ESR = 0.1Ω
Tantalum ESR = 0.1Ω
0.12Ω
Example 12. 5V/100mA Regulator with Shutdown and Output Disconnect
47µH
D2
U1
C1
100µF
10V
2.0V to 3.1V
2 Cell
MIC2570
SW
GND
5V
VOU T
5V/70mA
1
4
C2
220µF
10V
2
7
Micrel
AVX
AVX
Motorola
Motorola
Coilcraft
D1
8
IN
SYNC
U1
C1
C2
D1
D2
L1
MBRA140
L1
MBRS130L
MIC2570-1BM
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0100 Tantalum ESR = 0.1Ω
MBRA140T3
MBRS130L
DO3316P-473 DCR = 0.12Ω
Example 13. Reversed-Battery Protected Regulator
body diode
Q1
Si9434
2.0V to 3.1V
2 Cell
D3
C3
0.1µF
1N4148
C4
R1
0.1µF 100k
U1
C1
C2
D1
D2
D3
L1
Q1
Micrel
AVX
AVX
Motorola
Motorola
Motorola
Coilcraft
Siliconix
MBRA140
L1
D2
1N4148
U1
8
47µH
IN
C1
100µF
10V
MIC2570
SYNC
7
SW
5V
GND
D1
VOU T
5V/100mA
1
4
2
C2
220µF
10V
MIC2570-1BM
TPSD107M010R0100 Tantalum ESR = 0.1Ω
TPSE227M010R0100 Tantalum ESR = 0.1Ω
MBRA140T3
MBRS130LT3
MBRS130LT3
DO3316P-473 DCR = 0.12
Si9434 PMOS
Example 14. Improved Reversed-Battery Protected Regulator
MIC2570
12
August 2007
MIC2570
Micrel, Inc.
Component Cross Reference
Capacitors
AVX
Surface Mount
(Tantalum)
Sprague
Surface Mount
(Tantalum)
Sanyo
Through Hole
(OS-CON)
Sanyo
Through Hole
(AL Electrolytic)
330µF/6.3V
TPSE337M006R0100
593D337X06R3E2W
10SA220M
16MV330GX (330µF/16V)
220µF/10V
TPSE227M010R0100
593D227X0010E2W
10SA220M
16MV330GX (330µF/16V)
100µF/10V
TPSD107M010R0100
593D107X0010D2W
10SA100M
16MV330GX (330µF/16V)
33µF/25V
TPSE336M025R0300
593D336X0025E2W
35MV68GX (68µF/35V)
22µF/35V
TPSE226M035R0300
593D226X0035E2W
35MV68GX (68µF/35V)
Motorola
Surface Mount
(Schottky)
GI
Surface Mount
(Schottky)
IR
Surface Mount
(Schottky)
Motorola
Through Hole
(Schottky)
MBRA140T3
SS14
10MQ40
1N5819
Diodes
1A/40V
1A/20V
1N5817
Inductors
Coilcraft
Surface Mount
(Button Cores)
22µH
DO3308P-223
47µH
DO3316P-473
50µH
Coiltronics
Surface Mount
(Torriod)
Sumida
Surface Mount
(Button Cores)
Sumida
Through Hole
(Button Cores)
CD75-470LC
RCH-106-470k
CTX50-4P
Suggested Manufacturers List
Inductors
Capacitors
Diodes
Transistors
Coilcraft
1102 Silver Lake Rd.
Cary, IL 60013
tel: (708) 639-2361
fax: (708) 639-1469
AVX Corp.
801 17th Ave. South
Myrtle Beach, SC 29577
tel: (803) 448-9411
fax: (803) 448-1943
General Instruments (GI)
10 Melville Park Rd.
Melville, NY 11747
tel: (516) 847-3222
fax: (516) 847-3150
Siliconix
2201 Laurelwood Rd.
Santa Clara, CA 96056
tel: (800) 554-5565
Coiltronics
6000 Park of Commerce Blvd.
Boca Raton, FL 33487
tel: (407) 241-7876
fax: (407) 241-9339
Sanyo Video Components Corp.
2001 Sanyo Ave.
San Diego, CA 92173
tel: (619) 661-6835
fax: (619) 661-1055
International Rectifier Corp.
233 Kansas St.
El Segundo, CA 90245
tel: (310) 322-3331
fax: (310) 322-3332
Zetex
87 Modular Ave.
Commack, NY 11725
tel: (516) 543-7100
Sumida
Suite 209
637 E. Golf Road
Arlington Heights, IL
tel: (708) 956-0666
fax: (708) 956-0702
Sprague Electric
Lower Main St.
60005 Sanford, ME 04073
tel: (207) 324-4140
Motorola Inc.
MS 56-126
3102 North 56th St.
Phoenix, AZ 85018
tel: (602) 244-3576
fax: (602) 244-4015
August 2007
13
MIC2570
MIC2570
Micrel, Inc.
Evaluation Board Layout
Component Side and Silk Screen (Not Actual Size)
Solder Side and Silk Screen (Not Actual Size)
MIC2570
14
August 2007
MIC2570
Micrel, Inc.
Package Information
0.026 (0.65)
MAX)
PIN 1
0.157 (3.99)
0.150 (3.81)
DIMENSIONS:
INCHES (MM)
0.050 (1.27)
TYP
0.064 (1.63)
0.045 (1.14)
0.197 (5.0)
0.189 (4.8)
0.020 (0.51)
0.013 (0.33)
45°
0.0098 (0.249)
0.0040 (0.102)
0°–8°
0.010 (0.25)
0.007 (0.18)
0.050 (1.27)
0.016 (0.40)
SEATING
PLANE
0.244 (6.20)
0.228 (5.79)
8-Pin SOIC (M)
MICREL INC.
2180 FORTUNE DRIVE
SAN JOSE, CA 95131
USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
This information furnished by�
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not�
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's
use or sale of Micrel Pr�
Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Inc.
August 2007
15
MIC2570