MIC2544-2YMTR [MICROCHIP]
0.1A BUF OR INV BASED PRPHL DRVR, PDSO8, LEAD FREE, SOP-8;
| 型号： | MIC2544-2YMTR |
| 厂家： | 
MICROCHIP |
| 描述： | 0.1A BUF OR INV BASED PRPHL DRVR, PDSO8, LEAD FREE, SOP-8 驱动 光电二极管 接口集成电路 |
| 文件： | 总14页 (文件大小：1295K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC2544/2548
Programmable Current Limit
High-Side Switch
General Description
Features
The MIC2544 and MIC2548 are integrated, high-side
power switches optimized for low loss DC power switching
and other power management applications, including
Advanced Configuration and Power Interface (ACPI).
The MIC2544/48 is a cost-effective, highly integrated
solution that requires few external components to satisfy
USB and ACPI requirements.
• 2.7V to 5.5V input
• Adjustable current-limit up to 1.5A
• Reverse current flow blocking (no “body diode”)
• 75μA typical on-state supply current
• 1μA typical off-state supply current
• 120mΩ maximum on-resistance
• Open-drain fault flag
Load current management features include a precision
resistor-programmable output current-limit and a soft-start
circuit which minimizes inrush current when the switch is
enabled. Thermal shutdown, along with current-limit,
protects the switch and the attached device.
• Thermal shutdown
• Thermal shutdown output latch (MIC2548)
• 2ms (slow) turn-on and fast turnoff
• Available with active-high or active-low enable
The MIC2544/48’s open-drain flag output is used to
indicate current-limiting or thermal shutdown to a local
controller. The MIC2548 has an additional internal latch
which turns the output off upon thermal shutdown
providing robust fault control. The enable signal is
compatible with both 3V and 5V logic, and is also used as
the thermal shutdown latch reset for the MIC2548.
Applications
• USB power distribution
• PCI bus power switching
• Notebook PC
• ACPI power distribution
• PC card hot swap applications
• Inrush current-limiting
The MIC2544 and MIC2548 are available in active-high
and active-low enable versions in the 8-pin SOIC
(small-outline integrated circuit) and 8-pin MSOP (micro-
small-outline package).
_________________________________________________________________________________________________________
Typical Application
Typical Advanced Configuration and Power Interface (ACPI) Application
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-043010
April 2010
Micrel, Inc.
MIC2544/2548
Ordering Information*
Part Number
Enable
Latch*
Temperature Range
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
Package
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
8-pin SOIC
8-pin MSOP
Pb-Free
MIC2544-1BM
MIC2544-1BMM
MIC2544-2BM
MIC2544-2BM
MIC2544-1YM
MIC2544-1YMM
MIC2544-2YM
MIC2544-2YMM
MIC2548-1BM
MIC2548-1BMM
MIC2548-2BM
MIC2548-2BMM
MIC2548-1YM
MIC2548-1YMM
MIC2548-2YM
MIC2548-2YMM
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
*Thermal Shutdown Latch
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MIC2544/2548
Pin Configuration
8-pin SOIC (M)
8-Pin MSOP (MM)
Note: Pins 4 and 5 for SOIC and MSOP are different.
Pin Description
Pin Number
MSOP-8
Pin Number
SOIC-9
Pin Name
Pin Function
Enable (Input): Logic-compatible enable input. Active-high (-1) or active-
low (-2). High input >1.7V typical; low input <1.5V typical. Do not float.
MIC2548 only: Also resets thermal shutdown latch.
1
1
2
EN
Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent
or thermal shutdown conditions. MIC2548 only: latched low on thermal
shutdown.
2
FLG
3
5
3
4
GND
ILIM
IN
Ground.
1
Current Limit: Sets current-limit threshold using an external resistor, RSET
connected to ground. 154Ω < RSET < 2.29kΩ.
7
7
Input: Output MOSFET drain. Also powers internal circuitry.
Switch (Output): Output MOSFET source. Pins 6 and 8 must be externally
connected.
6,8
4
6,8
5
OUT
NC
Not internally connected.
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MIC2544/2548
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN)....................................................+7.0V
Output Voltage (VOUT) .................................................+7.0V
Output Current (IOUT).................................Internally Limited
Enable Input (VEN).................................. –0.3V to VIN+0.3V
Fault Flag Voltage (VFLG).............................................+7.0V
Fault Flag Current (IFLG) ..............................................50mA
Storage Temperature (Ts) .........................–65°C to +150°C
Junction Temperature (TJ) ........................Internally Limited
Lead Temperature (soldering, 5 sec.)........................ 260°C
ESD Rating(3)..................................................................2kV
Supply Voltage (VIN)..................................... +2.7V to +5.5V
Current Limit Set Range................................... 0.1A to 1.5A
Ambient Temperature (TA) ..........................–40°C to +85°C
Package Thermal Resistance
SOIC (θJA)........................................................160°C/W
MSOP (θJA) ......................................................206°C/W
Electrical Characteristics
VIN = +5V; TA = 25°C, bold values indicate –40°C to +85°C, unless noted.
Symbol Parameter
Condition
Min
Typ
0.75
75
1.7
1.5
1
Max
5
Units
μA
μA
V
Switch off, OUT = open(4)
Switch on, OUT = open(4)
Enable high(4)
#
Supply Current
160
2.4
VEN
Enable Input Voltage
Enable low(1)
0.8
V
Enable Input Capacitance
Switch Resistance
Note 5
pF
mΩ
V
RDS(on)
IOUT = 500mA
80
230
230
1
120
276
299
10
5
IOUT = 100mA to 1A, VOUT=1V to 4V(6)
IOUT = 500mA to 1.5A, VOUT=1V to 4V(6)
Switch off
184
161
Current Limit Factor
V
Output Leakage Current
Output Turn-On Delay
Output Turn-On Rise Time
Output Turn-Off Delay
Output Turn-Off Fall Time
μA
ms
ms
μs
μs
°C
°C
Ω
tON
TR
1
1
2
RL = 10Ω, CL = 1μF, Figures 1a, 1b
RL = 10Ω, CL = 1μF, Figures 1a, 1b
RL = 10Ω, CL = 1μF, Figures 1a, 1b
RL = 10Ω, CL = 1μF, Figures 1a, 1b
TJ increasing
2
5
TOFF
TF
22
21
140
130
4
Overtemperature Threshold Shutdown
Error Flag Output Resistance
TJ decreasing
15
20
1
VIN = 5V, IL = 10μA
5
VIN = 3.3V, IL = 10μA
VFLG = 5V
Ω
Error Flag Off Current
0.01
μA
μs
μs
μs
μs
EN Pulse Reset Width
MIC2548 thermal shutdown latch
MIC2548(6)
VOUT = 0V(6)
5
0
VIN to EN Set-Up
Current-Limit Response Time
Overcurrent Flag Response Time
25
5
VOUT = VIN/2 to FLG low
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Off is ≤0.8V and on is ≥2.4V for the MIC2544-1 and MIC2548-1. Off is ≥2.4V and on is ≤0.8V for the MIC2544-2 and MIC2548-2. The enable input
has about 200mV of hysteresis.
5. Guaranteed by design but not production tested.
230V
6. Current limit threshold is determined by ILIMIT
=
, where RSET is in ohms.
RSET
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MIC2544/2548
Test Circuit
Functional Characteristics Test Circuit
Timing Diagrams
Figure 1a. MIC2544/48-1
Figure 1b. MIC2544/48-2
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MIC2544/2548
Timing Diagrams continued
Figure 2a. MIC2548-2 Timing: Output is reset by toggling EN
Figure 2b. MIC2544-2 Timing
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MIC2544/2548
Typical Characteristics
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MIC2544/2548
Typical Characteristics continued
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Functional Characteristics
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MIC2544/2548
Block Diagram
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MIC2544/2548
Functional Description
Adjustable Current-Limit
The MIC2544 and MIC2548 are high-side N-channel
switches available with active-high or active-low enable
inputs. Fault conditions turn-off or inhibit turn-on of the
output transistor and activate the open-drain error flag
transistor making it sink current to ground.
The short-circuit current-limit is user-adjustable with an
external set resistor. Current-limit in the range of 100mA
to 1.5A is available with a set point accuracy of better
than ±20%. The current-limit circuit prevents damage to
the output MOSFET and external load.
The nominal current-limit value is set with an external
resistor between ILIM and GND. For a desired current-
limit, the value of the external set resistor is given by:
Input and Output
IN is the power supply connection to the logic circuitry
and the drain of the output MOSFET. OUT is the source
of the output MOSFET. In a typical circuit, current flows
from IN to OUT toward the load. If VOUT is greater than
VIN, current will flow from OUT to IN since the switch is
bidirectional when enabled.
where:
154Ω < RSET <2.29kΩ
The output MOSFET and driver circuitry are also
designed to allow the MOSFET source to be externally
forced to a higher voltage than the drain (VOUT > VIN)
when the switch is disabled. In this situation, the
MIC2544/48 avoids undesirable current flow from OUT
to IN. Both OUT pins must be connected together.
For example, to set a 1A nominal current-limit, RSET is
calculated as:
Thermal Shutdown
Current through RSET increases with OUT current.
The voltage across RSET could be monitored with a high
impedance comparator to provide an indication of output
current. RSET should be between 154Ω ±0.5% and
2.29kΩ ±0.5%.
Thermal shutdown shuts off the output MOSFET and
signals the fault flag if the die temperature exceeds
140°C. 10°C of hysteresis prevents the switch from
turning on until the die temperature drops to 130°C.
Overtemperature detection functions only when the
switch is enabled.
Short-Circuit Protection
In the event of a short circuit, the output current will fold
back to approximately 80% of the short-circuit current-
limit.
The MIC2548 features an internal latch which causes
the part to remain off after thermal shutdown until a reset
pulse is provided via the enable pin (pin 1). While in
current-limit, the thermal shutdown latch prevents on/off
cycling of the output.
Fault Flag
FLG is an N-channel, open-drain MOSFET output.
The faultflag is active (low) for current-limit or thermal
shutdown conditions. The flag output MOSFET is
capable of sinking a 10mA load to typically 100mV
above ground.
Refer to Figures 2a and 2b for timing diagram. The flag
remains low until reset.
Enable Input
EN must be driven logic high or logic low, or be pulled
high or low for a clearly defined input. Floating the input
may cause unpredictable operation. EN should not be
allowed to go negative with respect to GND, and VEN
should be less than or equal to VIN.
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MIC2544/2548
where:
Tj = junction temperature
TA = ambient temperature
JA = is the thermal resistance of the package
Application Information
Supply Filtering
A 0.1μF to 1μF bypass capacitor from IN to GND,
located near the MIC2544 and MIC2548, is strongly
recommended to control supply transients. Without a
bypass capacitor, an output short may cause sufficient
ringing on the input (from supply lead inductance) to
damage internal control circuitry.
θ
Transient Overcurrent Filter
The inrush current from the connection of a heavy
capacitive load may cause the fault flag to fall for 10μs to
200μs while the switch is in a constant-current mode,
charging the capacitance.
Input transients must not exceed the absolute maximum
supply voltage (VIN max = 6V) even for a short duration.
Adding an optional series resistor-capacitor (RSET2) in
parallel with RSET, as shown in Figure 4, allows the
transient current-limit to be set to a different value than
steady state. A typical USB hot-plug inrush is 2A to 3A
for 10μs to 20μs. If RSET is 435Ω (510mA), an RSET2 of
88Ω (2.5A) and CSET of 1μF (RC = 100μs) allows
transient surge of 3A to pass for 100μs without tripping
the overcurrent flag (FLG).
USB Power Distribution
The MIC2544 is ideal for meeting USB power distribution
requirements. Figure 4 depicts a USB Host application.
RSET should be set to a value providing a current-limit
>500mA.
Figure 3. Supply Bypassing
Power Dissipation
The accurate current-limit of the MIC2544 will reduce
power supply current requirements. Also, fast reaction to
short circuit faults prevent voltage droop in mobile
PC applications.
The device's junction temperature depends on several
factors such as the load, PCB layout, ambient
temperature, and package type. Equations that can be
used to calculate power dissipation and junction
temperature are found below.
Printed Circuit Board Hot-Plug
The MIC2544/48 are ideal inrush current-limiters suitable
for hot-plug applications. Due to the integrated charge
pump, the MIC2544/48 presents a high impedance when
off and slowly becomes a low impedance as it turns on.
This “softstart” feature effectively isolates power supplies
from highly capacitive loads by reducing inrush current
during hot-plug events. Figure 5 shows how the
MIC2544 may be used in a hot-plug application.
Calculation of power dissipation can be accomplished by
the following equation:
2
PD = RDS(on) × (IOUT
)
To relate this to junction temperature, the following
equation can be used:
Tj = PD × θJA + TA
Figure 4. USB Host Application
Note: MSOP package option uses pin 5 for ILIM. Pin 4 is not connected (NC). Bold lines indicate 0.1” wide, 1-oz. copper high-current traces.
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MIC2544/2548
Figure 5. Hot Plug Application
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MIC2544/2548
Package Information
8-pin SOIC (M)
8-Pin MSOP (MM)
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
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can 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 Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
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