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MIC2025/2075
Micrel, Inc.
MIC2025/2075
Single-Channel Power Distribution Switch MM8(R)
General Description
The MIC2025 and MIC2075 are high-side MOSFET switches optimized for general-purpose power distribution requiring circuit protection. The MIC2025/75 are internally current limited and have thermal shutdown that protects the device and load. The MIC2075 offers "smart" thermal shutdown that reduces current consumption in fault modes. When a thermal shutdown fault occurs, the output is latched off until the faulty load is removed. Removing the load or toggling the enable input will reset the device output. Both devices employ soft-start circuitry that minimizes inrush current in applications where highly capacitive loads are employed. A fault status output flag is provided that is asserted during overcurrent and thermal shutdown conditions. The MIC2025/75 is available in the MM8(R) 8-lead MSOP and 8-lead SOP.
Features
* * * * * * * * * * * * * 140m maximum on-resistance 2.7V to 5.5V operating range 500mA minimum continuous output current Short-circuit protection with thermal shutdown Fault status flag with 3ms filter eliminates false assertions Undervoltage lockout Reverse current flow blocking (no "body diode") Circuit breaker mode (MIC2075) reduces power consumption Logic-compatible input Soft-start circuit Low quiescent current Pin-compatible with MIC2525 UL File # E179633
Applications
* * * * * * USB peripherals General purpose power switching ACPI power distribution Notebook PCs PDAs PC card hot swap
Typical Application
VCC 2.7V to 5.5V 10k Logic Controller VIN 1F ON/OFF OVERCURRENT GND MIC2025/75 EN FLG GND NC OUT IN OUT NC 0.1F Load
UL Recognized Component MM8 is a registered trademark of Micrel, Inc. Micrel, Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
June 2010
1
MIC2025/2075
MIC2025/2075
Micrel, Inc.
Ordering Information
Part Number Standard MIC2025-1BM MIC2025-2BM MIC2025-1BMM MIC2025-2BMM MIC2075-1BM MIC2075-2BM MIC2075-1BMM MIC2075-2BMM Pb-Free MIC2025-1YM MIC2025-2YM MIC2025-1YMM MIC2025-2YMM MIC2075-1YM MIC2075-2YM MIC2075-1YMM MIC2075-2YMM Active High Active Low Active High Active Low Active High Active Low Active High Active Low -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C 8-Lead SOIC 8-Lead SOIC 8-Pin MSOP 8-Pin MSOP 8-Lead SOIC 8-Lead SOIC 8-Pin MSOP 8-Pin MSOP Enable Temperature Range Package
Pin Configuration
EN 1 FLG 2 GND 3 NC 4
MIC2025/75
8 7 6 5 OUT IN OUT NC
8-Lead SOIC (BM) 8-Lead MSOP (BMM)
Pin Description
Pin Number 1 2 Pin Name EN FLG Pin Function Switch Enable (Input): Active-high (-1) or active-low (-2). Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent or thermal shutdown conditions. Overcurrent condition must exceed tD in order to assert FLG. Ground not internally connected not internally connected Supply (Output): Pins must be connected together. Supply Voltage (Input).
3 4 5 6, 8 7
GND NC NC OUT IN
MIC2025/2075
2
June 2010
MIC2025/2075
Micrel, Inc.
Absolute Maximum Ratings (Note 1)
Supply Voltage (VIN) ..........................................-0.3V to 6V Fault Flag Voltage (VFLG) .............................................. +6V Fault Flag Current (IFLG)............................................. 25mA Output Voltage (VOUT) ................................................... +6V Output Current (IOUT) ............................... Internally Limited Enable Input (IEN) ..................................... -0.3V to VIN +3V Storage Temperature (TS) ........................ -65C to +150C ESD Rating, Note 3
Operating Ratings (Note 2)
Supply Voltage (VIN) ................................... +2.7V to +5.5V Ambient Temperature (TA) .......................... -40C to +85C Junction Temperature (TJ) ........................ Internally Limited Thermal Resistance SOP (JA) .......................................................... 160C/W MSOP(JA) ........................................................ 206C/W
Electrical Characteristics
VIN = +5V; TA = 25C, bold values indicate -40C TA +85C; unless noted Symbol IDD Parameter Condition Supply Current MIC20x5-1, VEN 0.8V, (switch off), OUT = open MIC20x5-2, VEN 2.4V, (switch off), OUT = open MIC20x5-1, VEN 2.4V, (switch on), OUT = open MIC20x5-2, VEN 0.8V, (switch on), OUT = open VEN Enable Input Voltage Enable Input Hysteresis IEN RDS(on) Enable Input Current Control Input Capacitance Switch Resistance Output Leakage Current OFF Current in Latched Thermal Shutdown tON tR tF tOFF ILIMIT Output Turn-On Delay Output Turn-On Rise Time Output Turnoff Delay Output Turnoff Fall Time Short-Circuit Output Current Current-Limit Threshold Short-Circuit Response Time tD Overcurrent Flag Response Delay Undervoltage Lockout Threshold VEN = 0V to 5.5V VIN = 5V, IOUT = 500mA -1 low-to-high transition high-to-low transition 0.8 2.1 1.9 200 0.01 1 90 100 50 1 0.5 2.5 2.3 50 50 0.5 0.60 0.7 0.85 24 1.5 1.5 2.2 2.0 3 3 2.5 2.3 7 8 2.7 2.5 6 5.9 100 100 1.25 1.25 140 160 10 1 Min Typ 0.75 0.75 Max 5 5 160 160 2.4 Units A A A A V V mV A pF m m A A ms ms s s A A s ms ms V V
VIN = 3.3V, IOUT = 500mA
MIC2025/2075 (output off) MIC2075 (during thermal shutdown state) RL = 10, CL = 1F, see "Timing Diagrams" RL = 10, CL = 1F, see "Timing Diagrams" RL = 10, CL = 1F, see "Timing Diagrams"
RL = 10, CL = 1F, see "Timing Diagrams" VOUT = 0V, enabled into short-circuit. VOUT = 0V to IOUT = ILIMIT (Short applied to output) VIN = 5V, apply VOUT = 0V until FLG low VIN rising VIN = 3.3V, apply VOUT = 0V until FLG low VIN falling ramped load applied to output, Note 4
June 2010
3
MIC2025/2075
MIC2025/2075
Symbol Parameter Error Flag Output Resistance Error Flag Off Current Overtemperature Threshold
Note 1. Note 2. Note 3. Note 4.
Micrel, Inc.
Condition IL = 10mA, VIN = 3.3V VFLAG = 5V TJ increasing IL = 10mA, VIN = 5V Min Typ 8 11 140 120 Max 25 40 10 Units A C C
TJ decreasing
Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. See "Functional Characteristics: Current-Limit Response" graph.
Test Circuit
IOUT Device Under OUT Test VOUT
RL
CL
Timing Diagrams
tR VOUT 90% 10% 90% 10% tF
Output Rise and Fall Times
VE N
50% tO F F tON
VOUT
90% 10%
Active-Low Switch Delay Times (MIC20x5-2)
VE N
50% tO F F tON 90% 10%
VOUT
Active-High Switch Delay Times (MIC20x5-1)
MIC2025/2075
4
June 2010
MIC2025/2075
Micrel, Inc.
180 160 120 100 80 60 40 20 140
S upply On-C urrent vs . T emperature
160 140
On-R es is tanc e vs . T emperature
5 4
T urn-O n R is e T ime vs . T emperature
V IN = 3.3V
RISE TIME (ms)
CURRENT (A)
5V
ON-RESISTANCE (m)
120 100 80 60 40 20 0 -40 -20
3.3V 5V
3 2 1 0 -40 -20 V IN = 5V R L =10 C L =1F 0 20 40 60 TEMPERATURE (C) 80 100
3.3V
I OUT = 500mA
0 -40 -20
0 20 40 60 TEMPERATURE (C)
80 100
0 20 40 60 TEMPERATURE (C)
80 100
200
S upply On-C urrent vs . Input V oltage
200
On-R es is tanc e vs . Input V oltage
5.0 4.0
T urn-O n R is e T ime vs . Input V oltage
150
150
+85C +25C -40C
RESISTANCE (m)
CURRENT (A)
RISE TIME (ms)
-40C 100 +25C +85C
+85C 100 +25C
3.0 2.0 1.0
50
50
-40C I OUT = 500mA
R L =10 C L =1F 3.0 3.5 4.0 4.5 INPUT VOLTAGE (V) 5.0 5.5
0 2.5
3.0 3.5 4.0 4.5 INPUT VOLTAGE (V)
5.0
5.5
0 2.5
3.0 3.5 4.0 4.5 INPUT VOLTAGE (V)
5.0
5.5
0 2.5
1000 800
S hort-C irc uit C urrent-L imit vs . T emperature
CURRENT LIMIT THRESHOLD (mA)
V IN = 3.3V
1200 1000 800 600 400 200
C urrent-L imit T hres hold vs . T emperature
V IN = 3.3V V IN = 5V
2.5 2.0
E nable T hres hold vs . T emperature
600 400 200 0 -40 -20 V IN = 5V
ENABLE THRESHOLD (V)
CURRENT LIMIT (mA)
V E N R IS ING V E N F ALLING
1.5 1.0 0.5 V IN = 5V 0 -40 -20 0 20 40 60 TEMPERATURE (C) 80 100
0 20 40 60 TEMPERATURE (C)
80 100
0 -40 -20
0 20 40 60 TEMPERATURE (C)
80 100
800 700
S hort-C irc uit C urrent-L imit vs . Input V oltage
CURRENT LIMIT THRESHOLD (mA)
+25C +85C
ENABLE THRESHOLD (V)
CURRENT LIMIT (mA)
600 500 400 300 200 100 0 2.5 3.0 3.5 4.0 4.5 INPUT VOLTAGE (V) 5.0 5.5 -40C
1200 1100 1000 900 800 700 600 +85C +25C -40C 500 400 300 200 100 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
C urrent-L imit T hres hold vs . Input V oltage
2.5 2.0
E nable T hres hold vs . Input V oltage
V E N R IS ING 1.5 1.0 0.5 0 2.5 V E N F ALLING
T A = 25C 3.0 3.5 4.0 4.5 INPUT VOLTAGE (V) 5.0 5.5
5.5
June 2010
5
MIC2025/2075
MIC2025/2075
Micrel, Inc.
5 4
F lag Delay vs . T emperature
V IN = 3.3V
5 4
F lag Delay vs . Input V oltage
+85C
3.0 2.5
UV L O T hres hold vs . T emperature
V IN R IS ING
DELAY TIME (ms)
DELAY TIME (ms)
3 2 1 0 -40 -20
V IN = 5V
UVLO THRESHOLD (V)
3 2 1 0 2.5
2.0 1.5 1.0 0.5 0 -40 -20
+25C
V IN F ALLING
-40C
0 20 40 60 TEMPERATURE (C)
80 100
3.0 3.5 4.0 4.5 INPUT VOLTAGE (V)
5.0
5.5
0 20 40 60 TEMPERATURE (C)
80 100
MIC2025/2075
6
June 2010
MIC2025/2075
Micrel, Inc.
Functional Characteristics
June 2010
7
MIC2025/2075
MIC2025/2075
Micrel, Inc.
MIC2025/2075
8
June 2010
MIC2025/2075
Micrel, Inc.
Block Diagram
EN OSC. THERMAL SHUTDOWN UVLO 1.2V REFERENCE IN
CHARGE PUMP
GATE CONTROL
CURRENT LIMIT
FLAG RESPONSE DELAY
OUT FLG
GND
Functional Description
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. 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 MIC2025/75 avoids undesirable current flow from OUT to IN. Thermal Shutdown Thermal shutdown is employed to protect the device from damage should the die temperature exceed safe margins due mainly to short circuit faults. Each channel employs its own thermal sensor. Thermal shutdown shuts off the output MOSFET and asserts the FLG output if the die temperature reaches 140C. The MIC2025 will automatically reset its output should the die temperature cool down to 120C. The MIC2025 output and FLG signal will continue to cycle on and off until the device is disabled or the fault is removed. Figure 2 depicts typical timing. If the MIC2075 goes into thermal shutdown, its output will latch off and a pull-up current source is activated. This allows the output latch to automatically reset when the load (such as a USB device) is removed. The output can also be reset by toggling EN. Refer to Figure 1 for details. Depending on PCB layout, package, ambient temperature, etc., it may take several hundred milliseconds from the incidence of the fault to the output MOSFET being shut off. The worst-case scenario of thermal shutdown is that of a short-circuit fault and is shown in the in the "Function Characteristics: Thermal Shutdown Response" graph.
Power Dissipation 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 of each channel and junction temperature are found below. Total power dissipation of the device will be the summation of PD for both channels. To relate this to junction temperature, the following equation can be used: where: TJ = PD x JA + TA TJ = junction temperature PD = RDS(on) x IOUT2
TA = ambient temperature
Current Sensing and Limiting The current-limit threshold is preset internally. The preset level prevents damage to the device and external load but still allows a minimum current of 500mA to be delivered to the load. The current-limit circuit senses a portion of the output MOSFET switch current. The current-sense resistor shown in the block diagram is virtual and has no voltage drop. The reaction to an overcurrent condition varies with three scenarios: Switch Enabled into Short-Circuit If a switch is enabled into a heavy load or short-circuit, the switch immediately enters into a constant-current mode, reducing the output voltage. The FLG signal is asserted indicating an overcurrent condition. See the Short-Circuit Response graph under Functional Characteristics.
JA = is the thermal resistance of the package
June 2010
9
MIC2025/2075
MIC2025/2075 Short-Circuit Applied to Enabled Output When a heavy load or short-circuit is applied, a large transient current may flow until the current-limit circuitry responds. Once this occurs the device limits current to less than the short-circuit current limit specification. See the Short-Circuit Transient Response graph under Functional Characteristics. Current-Limit Response--Ramped Load The MIC2025/75 current-limit profile exhibits a small foldback effect of about 200mA. Once this current-limit threshold is exceeded the device switches into a constant current mode. It is important to note that the device will supply current until the current-limit threshold is exceeded. See the Current-Limit Response graph under Functional Characteristics.
Micrel, Inc. Fault Flag The FLG signal is an N-channel open-drain MOSFET output. FLG is asserted (active-low) when either an overcurrent or thermal shutdown condition occurs. In the case where an overcurrent condition occurs, FLG will be asserted only after the flag response delay time, tD, has elapsed. This ensures that FLG is asserted only upon valid overcurrent conditions and that erroneous error reporting is eliminated. For example, false overcurrent conditions can occur during hot-plug events when a highly capacitive load is connected and causes a high transient inrush current that exceeds the current-limit threshold. The FLG response delay time tD is typically 3ms. Undervoltage Lockout Undervoltage lockout (UVLO) prevents the output MOSFET from turning on until VIN exceeds approximately 2.5V. Undervoltage detection functions only when the switch is enabled.
VE N VOUT ILIMIT IDC IOUT VF L G
Short-Circuit Faul t
Load Removed (Output Reset)
Thermal Shutdow n Reached
tD
Figure 1. MIC2075-2 Timing: Output Reset by Removing Load
Short-Circuit Faul t Load/Fault Removed
VE N VOUT ILIMIT IDC IOUT VF L G
Thermal Shutdow n Reached
tD
Figure 2. MIC2025-2 Timing
MIC2025/2075
10
June 2010
MIC2025/2075
Micrel, Inc. Universal Serial Bus (USB) Power Distribution The MIC2025/75 is ideally suited for USB (Universal Serial Bus) power distribution applications. The USB specification defines power distribution for USB host systems such as PCs and USB hubs. Hubs can either be self-powered or bus-powered (that is, powered from the bus). Figure 5 below shows a typical USB Host application that may be suited for mobile PC applications employing USB. The requirements for USB host systems is that the port must supply a minimum of 500mA at an output voltage of 5V 5%. In addition, the output power delivered must be limited to below 25VA. Upon an overcurrent condition, the host must also be notified. To support hot-plug events, the hub must have a minimum of 120F of bulk capacitance, preferably low-ESR electrolytic or tantulum. Refer to Application Note 17 for more details on designing compliant USB hub and host systems. For bus-powered hubs, USB requires that each downstream port be switched on or off under control by the host. Up to four downstream ports each capable of supplying 100mA at 4.4V minimum are allowed. In addition, to reduce voltage droop on the upstream VBUS, soft-start is necessary. Although the hub can consume up to 500mA from the upstream bus the hub must consume only 100mA max at start-up, until it enumerates with the host prior to requesting more power. The same requirements apply for bus-powered peripherals that have no downstream ports. Figure 6 shows a bus-powered hub.
Applications Information
Supply Filtering A 0.1F to 1F bypass capacitor positioned close to VIN and GND of the device 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. Printed Circuit Board Hot-Plug The MIC2025/75 are ideal inrush current-limiters suitable for hot-plug applications. Due to the integrated charge pump, the MIC2025/75 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 3 shows how the MIC2075 may be used in a hot-plug application. In cases of extremely large capacitive loads (>400F), the length of the transient due to inrush current may exceed the delay provided by the integrated filter. Since this inrush current exceeds the current-limit delay specification, FLG will be asserted during this time. To prevent the logic controller from responding to FLG being asserted, an external RC filter, as shown in Figure 4, can be used to filter out transient FLG assertion. The value of the RC time constant will be selected to match the length of the transient.
MIC2025-2 VC C to "Hot" Receptacle 0.1 F
1 2 3 4
EN FLG GND NC
OUT IN OUT NC
8 7 6 5
Backend Function CBULK
GND Adaptor Card
Figure 3. Hot Plug Application
V+ Logic Controller OVERCURRENT 10k R C MIC2025
1 2 3 4
EN FLG GND NC
OUT IN OUT NC
8 7 6 5
Figure 4. Transient Filter
June 2010
11
MIC2025/2075
MIC2025/2075
Micrel, Inc.
VC C 5.0V 4.50V to 5.25V Upstream VB U S 100mA max. VB U S D+ D- GND 1F
3.3V
10k 3.3V USB Controller VIN ON/OFF MIC2025/75 EN FLG GND NC OUT IN OUT NC 0.1F 120F
MIC5203-3.3 IN OUT GND 1F
Ferrite Beads VB U S D+ 0.01F D- GND USB Port
OVERCURRENT GND
Data
Data
Figure 5 USB Host Application
USB Upstream Connector VB U S D+ D- GND
3.3V
1.5k USB Logic Controller VIN ON/OFF OVERCURRENT GND MIC2025/75 EN FLG GND NC OUT IN OUT NC 0.1F 120F
MIC5203-3.3 (LDO) IN OUT GND 0.1F 1.5K
Ferrite Beads VB U S D+ 0.01F D- GND USB Downstream Connector (Up to four ganaged ports)
0.1F
Data
Data
Figure 6. USB Bus-Powered Hub
MIC2025/2075
12
June 2010
MIC2025/2075
Micrel, Inc.
Package Information
8-Lead SOIC (M)
MM8TM 8-Pin MSOP (MM)
June 2010
13
MIC2025/2075
MIC2025/2075
Micrel, Inc.
MICREL INC.
tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 web http://www.micrel.com
2180 FORTUNE DRIVE SAN JOSE, CA 95131
USA
This 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. (c) 2004 Micrel Incorporated
MIC2025/2075
14
June 2010

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