MIC2550AYML TR Micrel Inc, MIC2550AYML TR Datasheet - Page 8

• Manufacturer Part Number: MIC2550AYML TR
• Description: IC USB TRANSCEIVER 16-MLF
• Manufacturer: Micrel Inc
• Type: USB Transceiverr

Specifications of MIC2550AYML TR

• Number Of Drivers/receivers: 1/1
• Protocol: USB 2.0
• Voltage - Supply: 4 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 16-MLF®, QFN
• Number Of Transceivers: 1
• Esd Protection: YeskV
• Operating Supply Voltage (typ): Not RequiredV
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (max): Not RequiredV
• Operating Supply Voltage (min): Not RequiredV
• Pin Count: 16
• Mounting: Surface Mount
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-2661-2; MIC2550AYML TR; MIC2550AYMLTR; MIC2550AYMLTR

MIC2550A
Applications Information
The MIC2550A is designed to provide USB connectivity in
mobile systems where system supply voltages are not avail-
able to satisfy USB requirements. The MIC2550A can oper-
ate down to supply voltages of 2.5V and still meet USB
physical layer specifications. As shown in the system dia-
gram, the MIC2550A takes advantage of USB’s supply
voltage, V
age, V
digital I/O lines (VP, VM, RCV, OE#, SPD, and SUS pins)
interfacing to the system. Internal circuitry provides transla-
tion between the USB and system voltage domains. V
typically be the main supply voltage rail for the system.
In addition, a 3.3V, 10% termination supply voltage, V
provided to support speed selection. A 0.47µF (minimum)
capacitor from V
A 1.5K resistor is required between this pin and the D+ or D–
lines to respectively specify full-speed or low-speed opera-
tion.
Power Supply Configurations
V
When the V
path between V
from V
issue can arise in systems where V
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 V
during this condition. A solution is shown in Figure 8 below.
If the V
diode D1 is not necessary.
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 V
does not exceed 1mA total.
M9999-031805
IF
Note: *(Optional) See Text - Power Supply Configurations
/V
BUS
3.3V
IF
IF
IF
Figure 8. Solution to V
Power Controller
, is used to set the reference voltage used by the
to V
source is current limited to less than 50mA, then
BUS
Switched
Controller
BUS
USB Device
Figure 9. I/O Interface Using 3.3V
V
USB
DD
, to operate the transceiver. The system volt-
BUS
input pin is pulled to ground a low impedance
IF
TRM
and V
thereby damaging the MIC2550A. This
to ground is required to ensure stability.
I/O
BUS
VIF
BUS
MIC2550
VIF
V
RCV/OE#
P
can cause a high current flow
VBUS
/V
will prevent any current flow
MIC2550
M
/
IF
BUS
/V
ZHCS1000 or
BUS
VTRM
VBUS
*(Optional)
equivalent
is driven from a power
D1
Switching
1µF min
VBUS
TRM
VBUS
IF
TRM
will
, is
8
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 V
Suspend
When the suspend pin (SUS) is high, power consumption is
reduced to a minimum. V
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 Electronics Technologies (www.cooperet.com)
Littelfuse (www.littlefuse.com)
Non-multiplexed Bus
To save pin count for the USB logic controller interface, the
MIC2550A was designed with V
pins. To interface the MIC2550A with a non-multiplexed data
bus, resistors can be used for low cost isolation as shown in
Figure 11.
41206ESDA SurgX
0805ESDA SurgX
V0402MHS05
SP0503BAHT
Figure 11. MIC2550A Interface to
Non-multiplexed Data Bus
Figure 10. Powering Chip
from Internal 3.3V Source
USB Logic
Controller
(SIE)
VIF
®
®
MIC2550A
V
V
V
V
MO
PO
TRM
M
P
VTRM
VBUS
is not disabled. RCV, V
10k
10k
BUS
P
V
V
powers the entire chip.
and V
P
M
MIC2550
3.3V
M
as bidirectional
March 2005
Micrel, Inc.
P
and V
M