MIC2551AYTSTR - Micrel, Inc.

November 2008 1 M9999-112008

MIC2551A Micrel, Inc.

MIC2551A

USB Transceiver

General Description

The MIC2551A is a single chip transceiver that complies with

the physical layer specifications of the Universal Serial Bus

(USB) 2.0. It supports both full speed (12Mbps) and low

speed (1.5Mbps) operation and introduces superior edge

rate control, producing crisper eye diagrams, which ease the

task of passing USB compliance testing.

A unique, patented, dual supply voltage operation allows the

MIC2551A to reference the system I/F I/O signals to a supply

voltage down to 1.6V while independently powered by the

USB VBUS. This allows the system interface to operate at its

core voltage without addition of buffering logic and also

reduce system operating current.

Typical Application

System

Supply Voltage

USB SIE

Controller

VIF

OE#

RCV

VM D–

D+

VBUS

VTRM

GND

D–

D+ USB

Port

41206ESDA SurgX



GND

GPIO

MIC2551A

SPD

1.0µF (min)

10µF (max)

(See “Applications Inf ormation”

for additional suppliers.)

VCC

SUS

VPU

20Ω/±1%

VBUS

1.5k

1µF

CON

Typical Application Circuit

Features

•Compliant to USB Specification Revision 2.0 for full

speed (12Mbs) and low speed (1.5Mbps) operation

•Compliant to IEC-61000-4.2 (Level 3)

•Separate I/O supply with operation down to 1.6V

•Integrated speed select termination supply

•Very-low power consumption to meet USB suspend-

current requirements

•Small TSSOP and MLF® packages

•No power supply sequencing requirements

•Software controlled re-enumeration

Applications

•PDAs

•Palmtops

•Cell phones

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Micro

LeadFrame and MLF are registered trademarks of Amkor Technology.

SurgX is a registered trademark of Cooper Electronics Technologies.

Ordering Information

Part Number

Standard Pb-Free Package

MIC2551ABTS MIC2551AYTS 14-Pin TSSOP

MIC2551ABML MIC2551AYML 16-Pin MLF®

MIC2551A Micrel, Inc.

M9999-112008 2November 2008

Pin Configuration

1VIF

SPD

RCV

CON

GND

14 VBUS

VPU

VTRM

D+

D-

OE#

SUS

14-Pin TSSOP

16 15 14 13

5678

SPD

RCV

VTRM

D+

D–

OE#

VPU

VBUS

VIF

SUS

GND

CON

16-Pin MLF® (ML)

Pin Description

Pin Number Pin Number Pin Name I/O Pin Function

MIC2551ABTS MIC2551ABML

115 VIF I System Interface Supply Voltage: Used to provide reference

supply voltage for system I/O interface signaling.

21 SPD I Edge Rate Control: A logic HIGH operates at edge rates for “full

speed” operation. A logic LOW operates edge rates for “low

speed” operation.

32 RCV* O Receive Data: Output for USB differential data.

43 VP* I/O If OE# = 1, VP = Receiver output (+)

If OE# = 0, VP = Driver input (+)

54 VM* I/O If OE# = 1 VM, = Receiver output (-)

If OE# = 0, VM = Driver input (-)

65 CON I CONNECT (Input): Controls state of VPU. Refer to VPU pin

description for detail.

76 GND Ground Reference.

87 SUS I Suspend: Active-High. Turns off internal circuits to reduce supply

current.

99 OE#* I Output Enable: Active-Low. Enables the transceiver to transmit

data onto the bus. When inactive, the transceiver is in the receive

mode.

10/11 10/11 D–, D+* I/O Differential data lines conforming to the USB standard.

12 12 VTRM O 3.3V Reference Supply Output: Requires a minimum 0.1µF

decoupling capacitor for stability. A 1µF capacitor is recom-

mended

13 13 VPU O Pull-up Supply Voltage Output: Used to connect 1.5kΩ pull-up

speed detect resistor. If CON = 1, VPU is high impedance.

If CON = 0, VPU = 3.3V.

14 14 VBUS I USB Bus Supply Voltage: Used to power USB transceiver and

internal circuitry.

8,16 NC No connect.

* See Table 1 for description of logic states.

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MIC2551A Micrel, Inc.

SUS OE# D+, D– RCV VP/VM Function

00Driving Active Active Normal transmit mode.

01Receiving Active Active Normal receive mode.

10Hi-Z 0 Not active Low power state.

11Hi-Z 0 Active Receiving during suspend (low power

state) (Note 1).

Note 1. During suspend VP and VM are active in order to detect out-of-band signaling conditions.

Table 1. Function Selection

OE# = 0:

Input Output

VP VM D+ D- RCV Result

0000XSE0

01010Logic 0

10101Logic 1

1111XUndefined

OE# = 1:

Input Output

D+ D- VP VM RCV Result

0000XSE0

01010Logic 0

10101Logic 1

1111XUndefined

X - Undefined Table 2. Truth Table During Normal Mode

MIC2551A Micrel, Inc.

M9999-112008 4November 2008

Absolute Maximum Ratings (Note 1)

Supply Voltage (VBUS) .................................................6.5V

All Other Inputs ............................................. –0.5V to 5.5V

Ambient Storage Temperature................. –65°C to +150°C

Output Current (D+, D–)..........................................± 50mA

Output Current (all others) .......................................±15mA

Input Current ............................................................±50mA

ESD, Note 3

VBUS, D+, D–........................................................ ±11KV

All other pins .......................................................... ±2KV

Operating Ratings (Note 2)

Supply Voltage (VBUS)................................. 4.0V to 5.25V

Ambient Operating Temperature................ –40°C to +85°C

Package Thermal Resistance

TSSOP (θJA) .................................................. 100(°C/W)

MLF® (θJA) ....................................................... 59(°C/W)

DC Electrical Characteristics (System and USB Interface) (Note 7)

VIF = 3.6V, VBUS = 5V unless otherwise noted; TA = 25°C. Bold indicates specifications over temperature, –40°C to 85°C.

Symbol Parameter Conditions Min Typ Max Units

VBUS USB Supply Voltage 4.0 5.25 V

VIF System I/F Supply Voltage 1.6 3.6 V

VIL LOW-Level Input Voltage, Note 4 VIF–0.3 0.15VIF V

VIH HIGH-Level Input Voltage, Note 4 0.85VIF VIF+0.3 V

VOH HIGH-Level Output Voltage, Note 4 IOH = 20µA0.9VIF V

VOL LOW-Level Output Voltage, Note 4 IOL = 20µA0.1 V

IIL Input Leakage Current, Note 4 –5 5 µA

Symbol Parameter Conditions Min Typ Max Units

SPD SUS OE# Voltage Load

101 1 5µA

100 1 5µA

001 1 5µA

IIF VIF Supply Current 0 0 0 VBUS = 5.25V 1 5µA

010 VIF = 3.6V 1 5µA

100 f = 6MHz CLOAD 325 650 µA

= 50 pF, Note 7

f = 750kHz

000 CLOAD = 600 pF 40 75 µA

Note 7

101 800 1100 µA

100 3000 5000 µA

001 230350 µA

000 400700 µA

IVBUS VBUS Supply Current 0 1 0 VBUS = 5.25V 130 200 µA

100 VIF = 3.6V f = 6MHz CLOAD 7.3 10 mA

= 50 pF, Note 7

f = 750kHz

000 CLOAD = 600 pF 3.6 5mA

Note 7

IVPULEAK VPU Leakage Current CON = 1, VPU = 0V –5 5 µA

IVIFLEAK VIF Leakage Current VIF = 3.6V, VBUS = 0V –5 5 µA

VPU Pull-Up Output Voltage ITERM = 200µA, VBUS = 4.0 to 5.25V 3.0 3.3 3.6 V

RSW Internal Pull-Up Termination ITERM = 10mA, VBUS = 4.0 to 5.25V 10 Ω

ESD Protection

IEC-1000-4-2 Air Discharge 10 pulses ±8kV

(D+, D–, Contact Discharge 10 pulses ±9kV

VBUS only)

November 2008 5 M9999-112008

MIC2551A Micrel, Inc.

DC Electrical Characteristics (Transceiver) (Note 7)

Symbol Parameter Conditions Min Typ Max Units

Leakage Current

ILO Hi-Z State Data Line Leakage 0V < VIN < 3.3V, SUS = 1 –10 10 µA

(Suspend Mode)

Input Levels

VDI Differential Input Sensitivity |(D+) – (D–)| 0.2 V

VCM Differential Common Mode Range Includes VDI range 0.8 2.5 V

VSE Single-Ended Receiver Threshold 0.8 2.0 V

Receiver Hysteresis 200 mV

Output Levels

VOL Static Output Low RL = 1.5kΩ to 3.6V 0.3 V

VOH Static Output High RL = 15kΩ to GND 2.8 3.6 V

Capacitance

CIN Transceiver Capacitance Pin to GND 10 pF

ZDRV Driver Output Resistance Steady state drive 816 24 Ω

AC Electrical Characteristics (Notes 6, 7)

Driver Characteristics (Low Speed)

TRTransition Rise Time CL = 50pF, Figure 2 75 ns

CL = 600pF 300

TFTransition Fall Time CL = 50pF, Figure 2 75 ns

CL = 600pF 300

TR, TFRise/Fall Time Matching (TR, TF)80125 %

VCRS Output Signal Crossover Voltage 1.3 2.0 V

Driver Characteristics (Full Speed)

TRTransition Rise Time CL = 50pF, Figure 2 4 20 ns

TFTransition Fall Time CL = 50pF, Figure 2 4 20 ns

TR, TFRise/Fall Time Matching (TR, TF)90111.11 %

VCRS Output Signal Crossover Voltage 1.3 2.0 V

Transceiver Timing

tPVZ OE# to RCVR Tri-State Delay Figure 1 15 ns

tPZD Receiver Tri-State to Transmit Delay Figure 1 15 ns

tPDZ OE# to DRVR Tri-State Delay Figure 1 15 ns

tPZV Driver Tri-State to Receive Delay Figure 1 15 ns

tPLH VP, VM to D+, D– Propagation Delay Figure 4 15 ns

tPHL

tPLH D+, D– to RCV Propagation Delay Figure 3 15 ns

tPHL

tPLH D+, D– to VP, VM Propagation Delay Figure 3 8 ns

tPHL

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, 1.5k in series with 100pF.

Note 4. Specification applies to the following pins: SUS, SPD, RCV, CON, RCV, VP, VM, OE#.

Note 5. Characterized specification(s), but not production tested.

Note 6. All AC parameters guaranteed by design but not production tested.

Note 7. Specification for packaged product only.

MIC2551A Micrel, Inc.

M9999-112008 6November 2008

Timing Diagrams

PVZ

OE#

D+/D–

TRANSMIT RECEIVE

PZD

PDZ

PZV

Figure 1. Enable and Disable Times

Rise Time F all Time

Differential

Data Lines

10%

90%

10%

90%

Figure 2. Rise and Fall Times

PLH

CRS

D–

D+ V

CRS

Differential

Data Lines

PHL

Figure 3. Receiver Propagation Delay

PLH

CRS

D–

D+ V

CRS

Differential

Data Lines

PHL

Figure 4. Driver Propagation Delay

Test Circuits

D.U.T. 25pF

Figure 5. Load for VP, VM, RCV

D.U.T.

15k

20Ω

VTRM

Figure 6. Load for D+, D–

November 2008 7 M9999-112008

MIC2551A Micrel, Inc.

Functional Diagram

To Internal

Circuitry

VBUS

VTERM

VPU

D+

D–

Level

Translator

LDO

Regulator

VIF

CON

SPD

OE#

RCV

SUS

GND

MIC2551A

Applications Information

The MIC2551A is designed to provide USB connectivity in

mobile systems where available system supply voltages are

not able to satisfy USB requirements. The MIC2551A can

operate down to supply voltages of 1.6V and still meet USB

physical layer specifications. As shown in the circuit above,

the MIC2551A takes advantage of the USB supply voltage,

VBUS, to operate the transceiver. The system voltage, VIF, is

used to set the reference voltage used by the digital I/O lines

interfacing to the system controller. Internal circuitry provides

translation between the USB and system voltage domains.

VIF will typically be the main supply voltage rail for the

controller.

In addition, a 3.3V, 10% termination supply voltage, (VPU), is

provided to support speed selection. VPU can be disabled or

enabled under software control via the CON input. This

allows for software-controlled connect or disconnect states.

A 1.5k resistor is required to be connected between this pin

and the D+ or D– lines to respectively specify high speed or

low speed operation.

The use of ESD transient protection devices is not required

for operation, but is recommended. The MIC2551A is ESD

rated for 11kV at the VBUS and D+, D– pins and 2kV for all

other pins.

MIC2551A Micrel, Inc.

M9999-112008 8November 2008

Power Supply Configuration

The MIC2551A can be set up for different power supply

configurations which modify the behavior of the device. Both

VBUS and VIF have special thresholds that detect when they

are either removed or grounded. Table 3 depicts the behavior

under the different power supply configuration scenarios that

are explained below.

Normal Mode

VBUS is connected to the 5.0V USB bus voltage and VIF is

connected to a supply voltage in the range of 1.6V to 3.6V. In

this case VTRM supplies a 3.3V voltage for powering the

speed select resistor via VPU depending on the state of CON

pin.

Disconnect Mode

VIF is connected to a supply in a range of 1.6V to 3.6V and

VBUS is open or grounded. If VBUS is opened while transmit-

ting, the data lines (D+, D–) have sharing capability and may

be driven with external devices up to approximately 3.6V if

and only if SUSPEND is enabled (SUS = 1). With VBUS

ground, D+, D– sharing mode is not permitted.

Disable Mode

VBUS is connected to the 5.0V USB bus voltage and VIF is

open. All logic controlled inputs become high impedances,

thus minimal current will be supplied by VIF if the input pins are

pulled up to an external source.

Alternate Power Supply Configuration Options

I/O Interface Using 3.3V

In systems where the I/O interface utilizes a 3.3V USB

controller, an alternate solution is shown in Figure 7. No extra

components are required; however, the load on VTRM must

not exceed 10mA.

MIC2551

VIF VBUS

I/O

VBUS

VP/VM/

RCV/OE# VTRM

USB

Controller

VDD

3.3V

Figure 7. I/O Interface Using 3.3V

Signal Amplitude Respective to VIF

When operating the MIC2551A, it is necessary to provide

input signals which do not exceed VIF + 0.3V.

Suspend

When the suspend pin (SUS) is high, power consumption is

reduced to a minimum. VTRM is not disabled. RCV, VP and VM

are still functional to enable the device to detect USB activity.

For minimal current consumption in suspend mode, it is

recommended that OE# = 1, and SPD = 0.

Speed

The speed pin (SPD) sets D+/D– output edge rates by increas-

ing or decreasing biasing current sources within the output

drivers. For low speed, SPD = 0. For full speed, SPD = 1. By

setting SPD = 0 during idle periods, in conjunction with suspend

(SUS), the lowest quiescent current can be obtained. However,

designers must provide a 300ns delay between changing SPD

from 0 to 1 and transmission of data at full speed. This delay

ensures the output drivers have arrived at their proper operating

conditions. Failure to do so can result in leading edge distortion

on the first few data bits transmitted.

External ESD Protection

The use of ESD transient protection devices is not required

for operation, but is recommended. We recommend the

following devices or the equivalent:

Cooper Electronic Technologies (www.cooperet.com)

41206ESDA SurgX

0805ESDA SurgX

Littelfuse (www.littelfuse.com)

V0402MHS05

SP0503BAHT

Non-Multiplexed Bus

In order to save pin count for the USB logic controller

interface, the MIC2551A was designed with VP and VM as bi-

directional pins. To interface the MIC2551A with a non-

multiplexed data bus, resistors can be used for low cost

isolation as shown in Figure 8.

VPO

VMO

USB Logic

Controller

(SIE) MIC2551

10k

Figure 8. MIC2551A Interface to

Non-Multiplexed Data Bus

Configuration Mode VBUS/VTRM VIF Notes

Normal Connected Connected Normal supply configuration and operation.

Disconnect Open Connected VP/VM are HIGH outputs, RCV is LOW.

(D+/D– sharing) With OE# = 0 and SUS = 1, data lines may be driven with

external devices up to 3.6V.

With D+, D– floating, IIF draws less than 1µA.

Disconnect Ground Connected VP/VM are HIGH outputs, RCV is LOW.

With D+, D– floating, IIF draws less than 1µA.

Disable Mode Connected Open Logic controlled inputs pins are Hi-Z.

Prohibited Connected Ground Prohibited condition.

Table 3. Power Supply Configuration

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MIC2551A Micrel, Inc.

PCB Layout Recommendations

Although the USB standard and applications are not based in

an impedance controlled environment, a properly designed

PCB layout is recommended for optimal transceiver perfor-

mance. The suggested PCB layout hints are as follows:

•Match signal line traces (VP/VM, D+, D–) to

40ps, approximately 1/3 inch if possible. FR-4

PCB material propagation is about 150ps/inch,

so to minimize skew try to keep VP/VM, D+/D–

traces as short as possible.

•For every signal line trace width (w), separate

the signal lines by 1.5 – 2 widths. Place all other

traces at >2 widths from all signal line traces.

•Maintain the same number of vias on each

differential trace, keeping traces approximately

at same separation distance along the line.

•Control signal line impedances to ±10%.

•Keep RS as close to the IC as possible, with

equal distance between RS and the IC for both

D+ and D–.

MIC2551A Micrel, Inc.

M9999-112008 10 November 2008

Package Information

1.10 MAX (0.043)

0.15 (0.006)

0.05 (0.002)

1.00 (0.039) REF

0.65 BSC

(0.026)

8°

0°

6.4 BSC (0.252)



5.10 (0.200)

4.90 (0.193) 0.20 (0.008)



0.09 (0.003)

0.70 (0.028)

0.50 (0.020)

DIMENSIONS:

MM (INCH)

4.50 (0.177)

4.30 (0.169)

0.30 (0.012)

0.19 (0.007)

14-lead TSSOP (TS)

3.00BSC

2.75BSC

0.50 DIA 3.00BSC

12° max

SEATING

PLANE

2.75BSC

0.85+0.15

–0.65

0.65+0.15

–0.65

0.01+0.04

–0.01

0.23+0.07

–0.05

0.01+0.04

–0.01

0.42+0.18

–0.18

0.42+0.18

–0.18

0.23+0.07

–0.05

1.60+0.10

–0.10 PIN 1 ID

0.5 BSC

1.5 REF

0.42+0.18

–0.18

1.60+0.10

–0.10

0.40+0.05

–0.05

0.20 REF.

0.5BSC SECTION "C-C"

SCALE: NONE

FOR EVEN TERMINAL/SIDE

TOP VIEW BO TTOM VIEW

1. DIMENSIONS ARE IN mm.

2. DIE THICKNESS ALLOWABLE IS 0.305mm MAX.

3. PACKAGE WARPAGE MAX 0.05mm.

4. THIS DIMENSION APPLIES TO PLATED TERMINAL AND IS MEASURED

BETWEEN 0.20mm AND 0.25mm FROM TIP.

5. APPLIES ONLY FOR TERMINALS

Rev. 02

16-Pin MLF® (ML)

November 2008 11 M9999-112008

MIC2551A Micrel, Inc.

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 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.

16-Pin MLF® (ML)