USBN9603-28M National Semiconductor, USBN9603-28M Datasheet - Page 7

• Manufacturer Part Number: USBN9603-28M
• Description: USB Controller IC
• Manufacturer: National Semiconductor

Specifications of USBN9603-28M

• Interface: USB
• No. Of Pins: 28
• Peak Reflow Compatible (260 C): No
• Supply Voltage Max: 7V
• Leaded Process Compatible: No
• Controller Type, Ic: USB
• Package / Case: 28-WSOIC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

1.0 Signal/Pin Connection and Description
1.2 DETAILED SIGNAL/PIN DESCRIPTIONS
1.2.1
1.2.2
Oscillator Circuit
The XIN and XOUT pins may be connected to make a 24 MHz closed-loop ,crystal-controlled oscillator. Alternately, an ex-
ternal 24 MHz clock source may be input to clock the device. The internal crystal oscillator uses a 24 MHz fundamental crys-
tal. See Table 1 for typical component values and Figure 1 for the crystal circuit. For a specific crystal, please consult the
manufacturer for recommended component values.
If an external clock source is used, it is connected to XIN. XOUT should remain unconnected. Stray capacitance and induc-
tance should be kept as low as possible in the oscillator circuit. Trace lengths should be minimized by positioning the crystal
and external components as close as possible to the XIN and XOUT pins.
I/O
NA
NA
I/O
NA
NA
NA
NA
O
I
Power Supply
Oscillator, Clock and Reset
XIN
XOUT
CLKOUT Clock Output. This pin provides a programmable clock source. Upon hardware reset, this pin
RESET
Vcc
GND
AGND Analog Power Supply (AGND)
V3.3
Name
Name
Crystal Resonator
Resistor R1
Resistor R2
Capacitor C1
Capacitor C2
Digital Power Supply (V
Digital Power Supply (GND)
Transceiver 3.3V Voltage Supply. This pin can be used as the internal 3.3V voltage regulator
output. The regulator is intended to power only the internal transceiver and one external pull-up.
An external 1 F de-coupling capacitor is required on this pin. The voltage regulator output is dis-
abled upon reset. When the internal voltage regulator is left disabled, this pin must be used as a
3.3V supply input for the internal transceiver. This is the case during 3.3V operation.
Component
Crystal Oscillator Input. Input for internal 24 MHz crystal oscillator circuit. A 24 MHz funda-
mental crystal may be used.
Crystal Oscillator Output
sources a 4 MHz clock (there may be an initial phase discontinuity). It may be disabled, or con-
figured for different speeds, via the Clock Configuration register
Reset. This signal is active low. Signal conditioning is provided on this input to suppose use of
a simple, RC power-on reset circuit.
Table 1. Approximate Component Values
Resonance Frequency
Type
Maximum Serial Resistance
Maximum Shunt Capacitance
Load Capaciitance
CC
)
Parameters
7
(Continued)
Description
Description
24 MHz
Values
AT-Cut
10 pF
20 pF
15 pF
15 pF
1 M
50
0
Tolerance
N/A
20%
20%
5%
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