MIC2550A Micrel, Inc. MIC2550A Universal Serial Bus Transceiver General Description Features The MIC2550A is a single-chip transceiver that complies with the physical layer specifications for Universal Serial Bus (USB). The MIC2550A supports full-speed (12Mbps) and low-speed (1.5Mbps) operation and introduces superior edge rate control to produce crisper eye diagrams. As a result, the task of passing USB compliance testing is made easier. A unique, patented, dual supply voltage operation allows the MIC2550A to reference the system I/F I/O signals to a supply voltage down to 2.5V 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. • Compliant to USB Specification Revision 2.0 for low-speed (1.5Mbps) and full-speed (12Mbps) operation • Compliant to IEC-61000-4.2 (Level 2) • Operation down to 2.5V • Dual supply voltage operation • Integrated speed-select termination supply • Very low power consumption meets USB suspendcurrent requirements • Small 14-pin TSSOP and 16-pin MLF™ packages Applications • Personal digital assistants (PDA) • Palmtop computers • Cellular telephones Ordering Information Part Number Standard Pb-Free Package MIC2550ABTS MIC2550AYTS 14-Pin TSSOP MIC2550ABML MIC2550AYML 16-Pin MLF™ System Diagram System Supply Voltage 1.5k MIC2550A VIF HIGH SPEED VTRM LOW SPEED SPD VBUS 0.47µF System Interface OE# D+ RCV D– VP D– VM GND VBUS RS D+ 24Ω RS D– GND USB Interface Connector 24Ω 1µF SUS GND 1µF min 10µF max Cooper Electronics Technologies 41206ESDA SurgX (See “Applications Information” for additional suppliers.) MicroLeadFrame and MLF are trademarks of Amkor Technology. SurgX is a registered trademark of Cooper Electronics Technologies. Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com March 2005 1 M9999-031805 MIC2550A Micrel, Inc. VIF 1 NC VIF VBUS NC Pin Configuration 14 VBUS SPD 2 13 NC RCV 3 12 VTRM SPD 1 12 VTRM VP 4 11 D+ RCV 2 11 VM 5 10 D– VP VM 3 4 10 9 D+ D– OE# NC 6 9 OE# GND 7 8 SUS 16 15 14 13 NC GND SUS NC 5 6 7 8 14-Pin TSSOP (TM) 16-Pin MLF™ (ML) Pin Description Pin Name Pin Number Pin Number MIC2550ABTS MIC2550ABML VIF 1 15 System Interface Supply Voltage (Input): Determines logic voltage levels for system interface signaling to logic controller. SPD 2 1 Speed (Input): Edge rate control. Logic high selects full-speed edge rates. Logic low selects low-speed edge rates. RCV 3 2 Receive Data (Output): System interface receive data interface to logic controller. VP 4 3 Plus (Input/Output): System interface signal to logic controller. If OE# is logic 1, VP is a receiver output (+); If OE# is logic 0, VP is a driver input (+). VM 5 4 Minus (Input/Output): System interface signal to logic controller. If OE# is logic 1, VM is a receiver output (–); If OE# is logic 0, VM is a driver input (–). NC 6, 13 5, 8, 13 16 GND 7 6 Ground: Power supply return and signal reference. SUS 8 7 Suspend (Input): Logic high turns off internal circuits to reduce supply current. OE# 9 9 Output Enable (Input): Active low system interface input signal from logic controller. Logic low causes transceiver to transmit data onto the bus. Logic high causes the transceiver to receive data from the bus. D– 10 10 USB Differential Data Line – (Input/Output) D+ 11 11 USB Differential Data Line + (Input/Output) VTRM 12 12 Termination Supply (Output): 3.3V speed termination resistor supply output. VBUS 14 14 USB Supply Voltage (Input): Transceiver supply. M9999-031805 Pin Function Not internally connected 2 March 2005 MIC2550A Micrel, Inc. Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIF) ................................................... +6.5V Input Voltage (VBUS) ........................ –0.5V(min)/5.5V(max) Output Current (ID+, ID–) ........................................... ±50mA Output Current (all others) ....................................... ±15mA Input Current ............................................................ ±50mA Storage Temperature (TS) ......................... –65° to +150°C ESD, Note 3 VBUS, D+, D– ......................................................... ±10kV All other pins ........................................................... ±2kV Supply Voltage (VBUS) ................................. 4.0V to 5.25V Temperature Range (TA) ........................... –40°C to +85°C Junction Temperature (TJ) ........................................ 160°C Package Thermal Resistance TSSOP (θJA) ..................................................... 100°C/W Electrical Characteristics (Note 8) TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; typical values at VBUS = 5.0V, VIF = 3.0V; minimum and maximum values at VBUS = 4.0V to 5.25V, IFV = 2.5V to 3.6V; unless noted. Symbol Parameter Condition Min Typ Max Units System and USB Interface DC Characteristics VBUS USB Supply Voltage 4.0 5.25 V VIF System I/F Supply Voltage 2.5 5.25 V VIL Low-Level Input Voltage, Note 4 0.15VIF V VIH High-Level Input Voltage, Note 4 VOH High-Level Output Voltage, Note 4 IOH = 20µA VOL Low-Level Output Voltage, Note 4 IOL = 20µA IIL Input Leakage Current, Note 4 Symbol Parameter IIF IVBUS VTRM VIF Supply Current VBUS Supply Current Termination Voltage Conditions Voltage 0.85VIF V 0.9VIF V Min 0.1 V ±5 µA Typ Max Units SPD SUS OE# Load 1 0 1 1 5 µA 1 0 0 1 5 µA 0 0 1 1 5 µA 0 0 0 VBUS = 5.25V 1 5 µA 0 1 0 VIF = 3.6V 1 0 0 0 0 0 1 0 1 0 0 0 1 5 µA 325 650 µA 40 75 µA 1 800 1100 µA 0 3000 5000 µA 0 1 230 350 µA 0 0 400 700 µA 0 1 0 VBUS = 5.25V 130 200 µA 1 0 0 VIF = 3.6V 7.3 10 mA 0 0 0 3.6 5 mA 3.6 V f = 6MHz CLOAD = 50 pF, Note 7 f = 750kHz CLOAD = 600 pF Note 7 f = 6MHz CLOAD = 50 pF, Note 7 f = 750kHz CLOAD = 600 pF Note 7 ITRM = 2.5mA 3.0 ESD Protection IEC-1000-4-2 Air Discharge 10 pulses ±6 kV (D+, D–, VBUS only) 10 pulses ±6 kV March 2005 Contact Discharge 3 M9999-031805 MIC2550A Symbol Micrel, Inc. Parameter Condition Min Typ Max Units +10 µA Transceiver DC Characteristics ILO Hi-Z State Data Line Leakage 0V < VBUS < 3.3V, D+, D–, OE# = 1 pins only –10 VDI Differential Input Sensitivity |(D+) – (D–)|, VIN = 0.8V – 2.5V 0.2 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, Note 6 V 200 VOL Static Output Low, Note 5 OE# = 0, RL = 1.5kΩ to 3.6V VOH Static Output High, Note 5 OE# = 0, RL = 15kΩ to GND VCRS Output Signal Crossover Voltage Note 6 CIN Transceiver Capacitance, Note 6 Pin to GND ZDRV Driver Output Resistance Steady state drive, Note 6 6 CL = 50pF CL = 600pF 75 CL = 50pF CL = 600pF 75 T R ÷ TF mV 0.3 V 2.8 3.6 V 1.3 2.0 V 20 pF 18 Ω 300 ns ns 300 ns ns 80 125 % 1.3 2.0 V Low-Speed Driver Characteristics, Note 7 tR Transition Rise Time tF Transition Fall Time tR/tF Rise and Fall Time Matching VCRS Output Signal Crossover Voltage Full-Speed Driver Characteristics, Note 7 tR Transition Rise Time CL = 50pF 4 20 ns tF Transition Fall Time CL = 50pF 4 20 ns tR/tF Rise and Fall Time Matching T R ÷ TF 90 111.11 % VCRS Output Signal Crossover Voltage 1.3 2.0 V 15 ns Transceiver Timing, Note 7 tPVZ OE# to RCVR Tri-state Delay Figure 1 tPZD Receiver Tri-state to Transmit Delay Figure 1 tPDZ OE# to DRVR Tri-state Delay Figure 1 tPZV Driver Tri-state to Receiver Delay Figure 1 tPLH V+/V– to D+/D– Propagation Delay Figure 4 15 ns tPHL V+/V– to D+/D– Propagation Delay Figure 4 15 ns tPLH D+/D– to RCV Propagation Delay Figure 3 15 ns tPHL D+/D– to RCV Propagation Delay Figure 3 15 ns tPLH D+/D– to V+/D– Propagation Delay Figure 3 8 ns tPHL D+/D– to V+/D– Propagation Delay Figure 3 8 ns 15 15 15 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. Applies to the VP, VM, RCV, OE#, SPD, and SUS pins. Note 5. Applies to D+, D–. Note 6. Not production tested. Guaranteed by design. Note 7. Characterized specification(s), but not production tested. M9999-031805 ns 4 ns ns March 2005 MIC2550A Micrel, Inc. Timing Diagrams H VOE# L tPVZ tPZV VP VP/VM VM tPZD VD+ VD+/VD– VD– Figure 1. Enable and Disable Times VD+ Differential 90% Data Lines 10% VD– VCRS tR tF Figure 2. Rise and Fall Times Differential VD+ Data Lines V D– tPLH tPHL VOH Output V OL VSS Figure 3. Receiver Propagation Delay D+/D– to RCV, VP, and VM VOI Input V OL VSS tPLH tPHL Differential VD+ Data Lines V D– Figure 4. Driver Propagation Delay VP and VM to D+/D– March 2005 5 M9999-031805 MIC2550A Micrel, Inc. OE# = 0 (Transmit): Input Output VP VM D+ D– RCV Result 0 0 0 0 X SE0 0 1 0 1 0 Logic 0 1 0 1 0 1 Logic 1 1 1 1 1 X Undefined OE# = 1 (Receive): Input Output D+ D– VP VM RCV Result 0 0 0 0 X SE0 0 1 0 1 0 Logic 0 1 0 1 0 1 Logic 1 1 1 1 1 X Undefined Note. X = undefined. Table 1. Truth Table Test Circuits Test Point Device Under Test 500Ω 24Ω V 50pF For D+, D–: V = 0V for tPZH and tPHZ V = VBUS for tPZL and tPLZ Figure 5. Load for Enable and Disable Time (D+, D–) Device Under Test 25pF Figure 6. VP, VM and RCV Load VTRM Device Under Test 1.5kΩ* 24Ω 15kΩ CL CL = 50pF, full speed CL = 50pF, low speed (minimum timing) CL = 600pF, low speed (maximum timing) *1.5k on D– for low speed or D+ for high speed Figure 7. D+ and D– Load M9999-031805 6 March 2005 MIC2550A Micrel, Inc. Block Diagram SYSTEM I/F VOLTAGE DOMAIN VIF USB VOLTAGE DOMAIN Regulator VBUS VTRM TO INTERNAL CIRCUITS SPD D– D+ OE# RCV VP VM SUS GND March 2005 7 M9999-031805 MIC2550A Micrel, Inc. Internal 3.3V Source If the device is self-powered and has 3.3V available, the circuit in Figure 10 is yet another power supply configuration option. In this configuration, the internal regulator is disabled and the 3.3V source and not VBUS powers the entire chip. Applications Information The MIC2550A is designed to provide USB connectivity in mobile systems where system supply voltages are not available to satisfy USB requirements. The MIC2550A can operate down to supply voltages of 2.5V and still meet USB physical layer specifications. As shown in the system diagram, the MIC2550A takes advantage of USB’s 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 (VP, VM, RCV, OE#, SPD, and SUS pins) interfacing to the system. Internal circuitry provides translation between the USB and system voltage domains. VIF will typically be the main supply voltage rail for the system. In addition, a 3.3V, 10% termination supply voltage, VTRM, is provided to support speed selection. A 0.47µF (minimum) capacitor from VTRM to ground is required to ensure stability. A 1.5K resistor is required between this pin and the D+ or D– lines to respectively specify full-speed or low-speed operation. Power Supply Configurations VIF /VBUS Switched When the VBUS input pin is pulled to ground a low impedance path between VIF and VBUS can cause a high current flow from VIF to VBUS thereby damaging the MIC2550A. This issue can arise in systems where VBUS is driven from a power supply that can be switched off such as in the case of a desktop PC. Adding a Schottky diode, such as the ZHCS1000 by Zetex, in series with VBUS will prevent any current flow during this condition. A solution is shown in Figure 8 below. If the VIF source is current limited to less than 50mA, then diode D1 is not necessary. MIC2550 USB Device Power Controller VIF MIC2550A VIF VTRM Figure 10. Powering Chip from Internal 3.3V Source 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 increasing 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 Electronics Technologies (www.cooperet.com) 41206ESDA SurgX® 0805ESDA SurgX® D1 ZHCS1000 or equivalent VBUS VBUS *(Optional) 1µF min Littelfuse (www.littlefuse.com) V0402MHS05 SP0503BAHT Non-multiplexed Bus To save pin count for the USB logic controller interface, the MIC2550A was designed with VP and VM as bidirectional pins. To interface the MIC2550A with a non-multiplexed data bus, resistors can be used for low cost isolation as shown in Figure 11. Note: *(Optional) See Text - Power Supply Configurations Figure 8. Solution to VIF /VBUS Switching 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 9. This configuration has the advantage over Figure 8, in that no extra components are needed. Ensure that the load on VTRM does not exceed 1mA total. 3.3V USB Logic Controller (SIE) MIC2550 VDD VIF VBUS 3.3V VBUS VBUS MIC2550 VP VP 10k USB Controller VPO I/O VP/VM/ VTRM RCV/OE# VM VM 10k VMO Figure 9. I/O Interface Using 3.3V M9999-031805 Figure 11. MIC2550A Interface to Non-multiplexed Data Bus 8 March 2005 MIC2550A 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 performance. 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 >2w 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–. March 2005 9 M9999-031805 MIC2550A Micrel, Inc. Package Information 4.50 (0.177) 6.4 BSC (0.252) 4.30 (0.169) DIMENSIONS: MM (INCH) 0.30 (0.012) 0.19 (0.007) 5.10 (0.200) 4.90 (0.193) 0.20 (0.008) 0.09 (0.003) 1.10 MAX (0.043) 0.65 BSC (0.026) 1.00 (0.039) REF 8° 0° 0.15 (0.006) 0.05 (0.002) 0.70 (0.028) 0.50 (0.020) 14-Pin TSSOP (TS) 0.42 +0.18 –0.18 0.23 +0.07 –0.05 0.85 +0.15 –0.65 0.01 +0.04 –0.01 3.00BSC 1.60 +0.10 –0.10 0.65 +0.15 –0.65 0.20 REF. 2.75BSC 0.42 PIN 1 ID +0.18 –0.18 N 16 1 1 0.50 DIA 2 2 2.75BSC 3.00BSC 3 3 1.60 +0.10 –0.10 4 4 12° max 0.42 +0.18 –0.18 SEATING PLANE CC 0.23 +0.07 –0.05 4 0.5BSC 0.40 +0.05 –0.05 1.5 REF BOTTOM VIEW TOP VIEW CL 0.5 BSC SECTION "C-C" SCALE: NONE 0.01 +0.04 –0.01 1. 2. 3. 4. DIMENSIONS ARE IN mm. DIE THICKNESS ALLOWABLE IS 0.305mm MAX. PACKAGE WARPAGE MAX 0.05mm. 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) M9999-031805 10 March 2005 MIC2550A Micrel, Inc. 16-Pin MLF™ (ML) 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. © 2003 Micrel, Incorporated. March 2005 11 M9999-031805