MICREL MIC2537-1BM, MIC2537-2BM Datasheet

MIC2537 Micrel

MIC2537

Quad Power Distribution Switch

Preliminary Information

General Description

The MIC2537 is a cost-effective high-side power switch with
four independently controlled channels, optimized for bus­powered Universal Serial Bus (USB) applications. Few exter­nal components are necessary to satisfy USB requirements.

The MIC2537 satisfies the following USB requirements: each
switch channel supplies up to 100mA as required by USB
bus-powered downstream devices; fault current is limited to
typically 250mA, well below the UL 25VA safety require­ments; and a flag output is available to indicate fault condi­tions to the local USB controller. Soft start eliminates the
momentary voltage drop on the upstream port that may occur
when the switch is enabled in bus-powered applications.

Additional features include thermal shutdown to prevent
catastrophic switch failure from high-current loads and 3.3V
and 5V logic compatible enable inputs.

The MIC2537 is available in active-high and active-low ver­sions in a 16-lead SOP package.

Features

• Compliant to USB specifications

• 3V to 5.5V input

• 100mA minimum continuous load current per port

• 425mΩ typical on-resistance

• < 400mA current limit

• Individual open-drain fault flag leads

• 3V/5V-compatible enable inputs

• Active-high (-1) and active-low (-2) versions

• 100µA max. on-state supply current

• <1µA typical off-state supply current

• 16-lead SOP package

•–40°C to 85°C operation

Applications

• USB keyboards

• USB bus-powered docking stations

• Notebook docking stations

• Notebook PCs

• PDA

• General power distribution

Typical Application

Upstream V

4.75V to 5.25V
500mA max.

4.7
µF

BUS

MIC5207-3.3

LDO Regulator

IN OUT

GND

Bold lines indicate

0.1" wide, 1-oz. copper
high-current traces.

* 33µF, 16V tantalum or 100µF, 10V electrolytic per port

1µF

10k

3.3V USB Controller

GND

EN
OC

EN
OC
EN
OC
EN
OC

V+

D+
D–

10k 10k 10k

MIC2537

ENA
FLGA NC
ENB OUTA
FLGB

OUTB

ENC

OUTC

OUTDFLGC
END
FLGD

NC

GND

Ferrite

Bead

V

BUS

33µF*

IN

0.1
µF

33µF*

33µF*

33µF*

0.01µF

0.01µF

0.01µF

0.01µF

D+

D–

GND

V

BUS

D+

D–

GND

V

BUS

D+

D–

GND

V

BUS

D+

D–

GND

Downstream

USB

Port 1

100mA max.

Downstream

USB

Port 2

100mA max.

Downstream

USB

Port 3

100mA max.

Downstream

USB

Port 4

100mA max.

Typical Bus-Powered Hub

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

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MIC2537 Micrel

Ordering Information

Part Number Enable Temperature Range Package

MIC2537-1BM Active High –40°C to +85°C 16-Lead SOP
MIC2537-2BM Active Low –40°C to +85°C 16-Lead SOP

Pin Configuration

MIC2537-x

FLGA

ENA

1
2

16
15

FLGD
END

OUTA

GND

NC

OUTB

ENB

FLGB

Pin Description

Pin Number Pin Name Pin Function

1 FLGA Flag A: (Output): Channel A open-drain fault flag output.
2 ENA Enable A (Input): Channel A control input.
3 OUTA Output A: Channel A switch output.
4 GND Ground: Supply return. Connect both leads to ground.

5, 12 NC Not internally connected

6 OUTB Output B: Channel B switch output.
7 ENB Enable B (Input): Channel B control input.
8 FLGB Flag B (Output): Channel B open-drain fault flag output.

9 FLGC Flag C (Output): Channel C open-drain fault flag output.
10 ENC Enable C (Input): Channel C control input.
11 OUTC Output C: Channel C switch output.
13 IN Positive Supply Input
14 OUTD Output D: Channel D switch output.
15 END Enable D (Input): Channel D control input.
16 FLGD Flag D (Output): Channel D open-drain fault flag output.

3
4
5
6
7
8

16-Lead SOP (M)

14
13
12
11
10

9

OUTD
IN
NC
OUTC
ENC
FLGC

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MIC2537 Micrel

Absolute Maximum Ratings (Note 1)

Supply Voltage (V
Fault Flag Voltage (V
Fault Flag Current (I
Output Voltage (V
Output Current (I
Control Input (V

) .....................................................+6V

IN

)..............................................+6V

FLG

) ............................................25mA

FLG

) ..................................................+6V

OUT

)...............................Internally Limited

OUT

)......................................... –0.3V to 12V

EN

Operating Ratings (Note 2)

Supply Voltage (V
Ambient Operating Temperature (T
Thermal Resistance

SOP (θ

) ..........................................................120°C/W

JA

) ...................................... +3V to +5.5V

IN

) ........ –40°C to +85°C

A

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

Lead Temperature (Soldering 5 sec.) ....................... 260°C

ESD Rating, Note 3....................................................... 2kV

Electrical Characteristics

VIN = +5V; TA = 25°C; unless noted.

Parameter Condition Min Typ Max Units
Supply Current Note 4, switch off, OUTA–D = open 0.75 5 µA

Note 4, all switches on, OUTA–D = open 70 100 µA

Enable Input Threshold low-to-high transition 1.8 2.4 V

high-to-low transition, Note 4 0.8 1.6 V

Enable Input Current VEN = V

VEN = V
Enable Input Capacitance 1pF
Switch Resistance single switch, 100mA load 425 700 mΩ
Output Turn-On Delay RL = 50Ω, CL = 1µF, Note 5 0.51 ms
Output Turn-On Rise Time RL = 50Ω, CL = 1µF, Note 5 0.2 0.5 ms
Output Turnoff Delay RL = 50Ω, CL = 1µF, Note 5 150 300 µs
Output Turnoff Fall Time RL = 50Ω, CL = 1µF, Note 5 148 300 µs
Output Leakage Current each output (switch off) 1 10 µA
Current Limit Threshold ramped load applied to enable output, Note 6 300 500 mA
Continuous Load Current each output, FLG not active 100 mA
Short Circuit Current Limit each output (enabled into load), V
Overtemperature Shutdown TJ increasing 135 °C
Threshold TJ decreasing 125 °C
Error Flag Output Resistance VIN = 5V, IL = 10mA 10 Ω

VIN = 3.3V, IL = 10mA 12 Ω
Error Flag Off Current V

Note 1. Exceeding the absolute maximum rating may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
Note 4. Off is ≤ 0.8V and on is ≥ 2.4V for the MIC2537-1. Off is ≥ 2.4V and on is ≤ 0.8V for the MIC2537-2. The enable input has approximately

200mV of hysteresis. See control threshold charts.

Note 5. See “Timing Diagrams.”
Note 6. See “Functional Characteristics: Current-Limit Response” graph.

= 5V 0.01 1 µA

FLAG

= 2.4V 0.01 1 µA

OH(min)

= 0.8V 0.01 1 µA

OL(max)

= 4.0V 150 250 400 mA

OUT

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MIC2537 Micrel

Typical Characteristics

Supply Current

vs. Supply Voltage

100

80

60

40

20

SUPPLY CURRENT (µA)

0

23456

SUPPLY VOLTAGE (V)

TA = 25°C
R

= ∞

L

Ouput On-Resistance

Variation vs. Temperature

500

400

300

200

100

ON RESISTANCE (mΩ)

0

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

VIN = 5V
I

= 100mA

L

Supply Current

100

SUPPLY CURRENT (µA)

vs. Temperature

80

60

40

20

0

-40 -20 0 20 40 60 80 100

VIN = 5V

VIN = 3.3V

RL = ∞

TEMPERATURE (°C)

Overcurrent Threshold and

Current Limit vs. Supply Voltage

300

250

200

150

100

CURRENT (mA)

50

0

23456

SUPPLY VOLTAGE (V)

I

THR

I

LIM

TA = 25°C

Ouput On-Resistance

Variation vs. Supply Voltage

500

400

300

200

100

ON-RESISTANCE (mΩ)

0

23456

SUPPLY VOLTAGE (V)

TA = 25°C
I

= 100mA

L

Overcurrent Threshold, and

Current Limit vs. Temperature

300

250

200

150

100

CURRENT (mA)

50

0

-40 -20 0 20 40 60 80 100

I

THR

I

LIM

VIN = 5V

TEMPERATURE (°C)

Control Threshold

vs. Supply Voltage

2.0

1.5

1.0

0.5

ENABLE VOLTAGE (V)

V

IH

V

IL

TA = 25°C

0

23456

SUPPLY VOLTAGE (V)

Output Fall Time

1.5

1.0

TIME (µs)

0.5

vs. Temperature

VIN = 5V
C

= 0.01µF

L

R

= 44Ω

L

0

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

Control Threshold

vs. Temperature

2.0

1.5

1.0

0.5

THRESHOLD VOLTAGE (V)

0

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

V

IH

V

IL

VIN = 5V

Output Rise Time

vs. Temperature

VIN = 5V
C

= 0.01µF

L

R

= 44Ω

L

0

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

TIME (µs)

500

400

300

200

100

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