MIC2026-1BMTR - Micrel

MIC2026/2076

Dual-Channel Power Distribution Switch

UL Recognized Component

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 M9999-060410-B

General Description

The MIC2026 and MIC2076 are high-side MOSFET

switches optimized for general-purpose power distribution

requiring circuit protection.

The MIC2026/76 are internally current limited and have

thermal shutdown that protects the device and load.

The MIC2076 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 asserted during overcurrent

and thermal shutdown conditions. Transient faults are

internally filtered.

The MIC2026/76 are available in 8-pin DIP or 8-pin SOIC.

All support documentation can be found on Micrel’s web

site at www.micrel.com.

Features

• 140m maximum on-resistance per channel

• 2.7V to 5.5V operating range

• 500mA minimum continuous current per channel

• Shortcircuit protection with thermal shutdown

• Thermally isolated channels

• Fault status flag with 3ms filter eliminates false

assertions

• Undervoltage lockout

• Reverse current flow blocking (no “body diode”)

• Circuit breaker mode (MIC2076)

• Logic-compatible inputs

• Soft-start circuit

• Low quiescent current

• Pin compatible with MIC2526

• UL File # E179633

Applications

• USB peripherals

• General purpose power switching

• ACPI power distribution

• Notebook PCs

• PDAs

• PC card hot swap

___________________________________________________________________________________________________________

Typical Application

ENA OUTA

FLGAI N

FLGB GND

ENB OUTB

ON/OFF

OVERCURRENT

ON/OFF

MIC2026-2

Logic Controller

VCC

2.7V to 5.5V

0.1µF

VIN Load

Load

VCONT.

10k

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Ordering Information

Part Number

Standard Pb-Free

Enable Temperature

Range Package

MIC2026-1BM MIC2026-1YM(1) Active High 8-Pin SOIC

MIC2026-2BM MIC2026-2YM(1) Active Low 8- Pin SOIC

MIC2026-1BN — Active High 8- Pin DIP

MIC2026-2BN — Active Low 8- Pin DIP

MIC2076-1BM MIC2076-1YM(1) Active High 8- Pin SOIC

MIC2076-2BM MIC2076-2YM(1) Active Low 8- Pin SOIC

MIC2076-1BN — Active High 8-Pin DIP

MIC2076-2BN — Active Low

–40°C to +85°C

8-Pin DIP

Note:

1. RoHS compliant and Halogen free.

Pin Configur ation

1ENA

FLGA

FLGB

ENB

8OUTA

GND

OUTB

8-Pin SOIC (M)

8-Pin DIP (N)

Pin Description

Pin Number Pin Name Pin Function

1 ENA

Switch A Enable (Input): Logic-compatible, enable input. Active high (-1) or

active low (-2).

2 FLGA

Fault Flag A (Output): Active-low, open-drain output. Indicates overcurrent or

thermal shutdown conditions. Overcurrent conditions must last longer than tBDB in

order to assert FLGA.

3 FLGB

Fault Flag B (Output): Active-low, open-drain output. Low indicates overcurrent

or thermal shutdown conditions. Overcurrent conditions must last longer than tBDB

in order to assert FLGB.

4 ENB

Switch B Enable (Input): Logic-compatible enable input. Active-high (-1) or

active-low (-2).

5 OUTB Switch B (Output)

6 GND Ground

7 IN Input: Switch and logic supply input.

8 OUTA Switch A (Output)

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Absolute Maximum RatingsP

(1)

Supply Voltage (VBINB)........................................ –0.3V to +6V

Fault Flag Voltage (VBFLGB)................................................+6V

Fault Flag Current (IBFLGB) ..............................................25mA

Output Voltage (VBOUTB) ....................................................+6V

Output Current (IBOUTB) .................................Internally Limited

Enable Input (IBENB) ..................................... –0.3V to VIN + 3V

Storage Temperature (TBSB)........................–65°C to +150 °C

ESD Rating(3)

HBM......................................................................... 1kV

MM.........................................................................200V

Operating RatingsP

(2)

Supply Voltage (VBINB)..................................... +2.7V to +5.5V

Ambient Temperature (TBAB) .......................... –40°C to +85°C

Junction Temperature Range (TBJB)............. Internally Limited

Thermal Resistance

SOIC (θBJAB) ........................................................160°C/W

PDIP (θBJAB) ........................................................105°C/W

Electrical Characteristics(4)

VBINB = +5V; TBAB = 25°C, bold values indicate –40°C  TBAB  +85°C; unless noted

Symbol Parameter Condition Min Typ Max Units

MIC20x6-1, VBENA B= VBENB B 0.8V

(switch off), OUT = open

0.75 5 µA

MIC20x6-2, VBENA B= VBENB B 2.4V

(switch off), OUT = open

9.5

20 µA

MIC20x6-1, VBENA B= VBENB B 2.4V

(switch on), OUT = open

100 160 µA

IBDDB Supply Current

MIC20x6-2, VBENA B= VBENB B 0.8V

(switch on), OUT = open

100 160 µA

low-to-high transition 1.7 2.4 V Enable Input Threshold

high-to-low transition 0.8 1.45 V

VBENB

Enable Input Hysteresis 250 mV

Enable Input Current VBENB = 0V to 5.5V -1 0.01 1 µA

IBENB

Enable Input Capacitance 1 pF

VBINB = 5V, IBOUTB = 500mA 90

140 m RBDS(ON)B Switch Resistance

VBINB = 3.3V, IBOUTB = 500mA 100

170 m

Output Leakage Current MIC20x6-1, VENx  0.8V;

MIC20x6-1, VENx  2.4V, (output off)

10 µA

OFF Current in Latched

Thermal Shutdown

MIC2076

(during thermal shutdown state)

50 µA

tBONB Output Turn-On Delay RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 1.3 5 ms

RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 0.5 1.15 4.9 ms tBRB Output Turn-On Rise Time

RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 1.75 ms

tBOFFB Output Turn-Off Delay RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 35 100 µs

tBFB Output Turn-Off Fall Time RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 32 100 µs

IBLIMITB Short-Circuit Output Current VBOUTB = 0V, enabled into short-circuit 0.5 0.9 1.25 A

Current-Limit Threshold ramped load applied to output 0.65 1.0 1.25 A

Short-Circuit Response Time VBOUTB = 0V to IBOUTB = IBLIMITB

(short applied to output)

20 µs

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Symbol Parameter Condition Min Typ Max Units

VBINB = 5V, apply VBOUTB = 0V until FLG low 1.5 3 7 ms

tD Overcurrent Flag Response

Delay VBINB = 3.3V, apply VBOUTB = 0V until FLG low 3 ms

VBINB rising 2.2 2.4 2.7 V Undervoltage Lockout

Threshold VBINB falling 2.0 2.15 2.5 V

IBLB = 10mA, VBINB = 5V 10

25  Error Flag Output Resistance

IBLB = 10mA, VBINB = 3.3V 15 40 

Error Flag Off Current VBFLAGB = 5V 10 µA

TBJB increasing, each switch

TBJB decreasing, each switch

140

120

°C

Overtemperature ThresholdP

(5)

TBJB increasing, both switches

TBJB decreasing, both switches

160

150

°C

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.

4. Specification for packaged product only.

5. If there is a fault on one channel, that channel will shut down when the die reaches approximately 140°C. If the die reaches approximately 160°C,

both channels will shut down, even if neither channel is in current limit.

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Test Circuit

Device

Under

Test

OUT

VOUT

Timing Diagrams

90%

VOUT

10%

90%

10%

tRtF

Output Rise and Fall Times

VEN

50%

90%

VOUT

10%

tOFF

tON

Active-Low Switch Delay Times (MIC20x6-2)

VEN 50%

90%

VOUT

10%

tOFF

tON

Active-High Switch Delay Time (MIC20x6-1)

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Typical Characteristics

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Typical Characteristics (continue)

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Functional Characteristics

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Functional Characteristics (continue)

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Functional Characteristics (continue)

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Block Diagram

1.2V

REFERENCE

THERMAL

SHUTDOWN

CHARGE

PUMP

OUTB

UVLO

GATE

CONTROL

ENA

GATE

CONTROL

OUTA

FLGB

CHARGE

PUMP

ENB

OSC.

FLGA

CURRENT

LIMIT

CURRENT

LIMIT

GND

MIC2026/2076

FLAG

RESPONSE

DELAY

FLAG

RESPONSE

DELAY

MIC2026/2076 Block Diagra m

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 MIC2026/76 prevents 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 140°C and the

overheated channel is in current limit. The other channel

is not affected. If however, the die temperature exceeds

160°C, both channels will be shut off. Upon determining

a thermal shutdown condition, the MIC2076 will latch the

output off. In this case, 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 timing details.

The MIC2026 will automatically reset its output when the

die temperature cools down to 120°C. The MIC2026

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.

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. This time will be shortest in the

case of a dead short on the output.

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:

PD = RDS(on) × IOUT

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:

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TJ = PD × θJA + TA

where:

TJ = junction temperature

TA = ambient temperature

θJA = is the thermal resistance of the package

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.

Short-Circuit Applied to Enabled Output

When a heavy load or short-circuit is applied to an

enabled switch, 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.

Current-Limit Response—Ramped Load

The MIC2026/76 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 up to the current-limit

threshold.

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 of an overcurrent condition, 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 for

up to 1ms. 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.

VEN

VOUT

IOUT

Short-Circuit Fault

Thermal

Shutdown

Reached

Load and Fault Removed

(Output Reset)

VFLG

ILIMIT

ILOAD

3ms typ.

delay

Figure 1. MIC2076-2 Faul t Timing: Output Reset by Removing Load

VEN

VOUT

IOUT

Short-Circuit Fault

Thermal

Shutdown

Reached

Load/Fault

Removed

VFLG

ILOAD

ILIMIT

3ms typ.

delay

Figure 2. MIC2026-2 Faul t Timing

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Application Information

Supply Filtering

A 0.1µF to 1µF 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 MIC2026/76 are ideal inrush current-limiters for hot

plug applications. Due to their integrated charge pumps,

the MIC2026/76 present a high impedance when off and

slowly become a low impedance as their integrated

charge pumps turn on. This “soft-start” feature effectively

isolates power supplies from highly capacitive loads by

reducing inrush current. Figure 3 shows how the

MIC2076 may be used in a card hot-plug application.

In cases of extremely large capacitive loads (>400µF),

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 should be selected to

match the length of the transient, less tD(min) of the

MIC2026/76.

Universal Serial Bus (USB) Power Distribution

The MIC2026/76 are 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 shows a typical USB Host application

that may be suited for mobile PC applications employing

USB. The requirement 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 120µF of bulk capacitance, preferably low ESR

electrolytic or tantulum. Please 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.

ENA OUTA

FLGA

FLGB GND

OUTB

USB

Controller

ENB

USB Peripheral

Cable

o "Hot"

Receptacle

CBULK

GND

VBUS

4.7

µF

USB

Function

USB

Function

CBULK

SPN010012

Figure 3. Hot-Plug Application

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Figure 4. Transient Filter

Figure 5. USB Two-Port Host Application

Figure 6. USB Two-Port Bus-Powered Hub

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Package Information

8-Pin SOIC (M)

8-Pin DIP (N)

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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.

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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

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