LMX2542LQ2121 NSC [National Semiconductor], LMX2542LQ2121 Datasheet - Page 4

• Manufacturer Part Number: LMX2542LQ2121
• Description: PLLatinum Cellular and GPS Frequency Synthesizer System with Integrated VCO
• Manufacturer: NSC [National Semiconductor]

www.national.com
Pin No.
Pin Description
17
18
19
20
21
22
23
24
25
26
27
28
Pin Name
OSCin
GND
GND
GND
V
V
V
V
V
CE
NC
LD
CC
CC
CC
CC
CC
(Continued)
I/O
—
—
—
—
—
—
—
—
—
O
I
I
Power supply bias for the RF PLL charge pump. V
Bypass capacitors should be placed as close as possible to this pin and be connected
directly to the ground plane on the printed circuit board.
Power supply bias for the RF PLL digital circuits. V
Bypass capacitors should be placed as close as possible to this pin and be connected
directly to the ground plane on the printed circuit board.
Digital filtered lock detect output.
Chip Enable input. High Impedance CMOS input. When this pin is set HIGH, the RF
and IF synthesizer systems are powered up. Powerdown is then controlled through the
MICROWIRE. When this pin is set LOW, the device is asynchronously powered down
and the IF PLL charge pump output is forced to a high impedance state (TRI-STATE
Ground for the RF PLL digital circuits.
Reference oscillator input. The input is driven by an external AC coupled source. When
the OSC_FREQ bit is set LOW, a 19.20 MHz reference frequency should be used.
When the OSC_FREQ bit is set HIGH, a 19.68 MHz reference frequency should be
used.
Power supply bias for the reference oscillator buffer. V
Bypass capacitors should be placed as close as possible to this pin and be connected
directly to the ground plane on the printed circuit board.
Ground for the reference oscillator buffer.
Ground for the IF PLL digital circuits.
Power supply bias for the IF PLL digital circuits. V
Bypass capacitors should be placed as close as possible to this pin and be connected
directly to the ground plane on the printed circuit board.
No Connect. Do not connect to any node on the printed circuit board.
Power supply bias for the IF PLL buffer/ prescaler. V
Bypass capacitors should be placed as close as possible to this pin and be connected
directly to the ground plane on the printed circuit board.
4
Description
CC
CC
CC
CC
may range from 2.7V to 3.3V.
may range from 2.7V to 3.3V.
may range from 2.7V to 3.3V.
CC
may range from 2.7V to 3.3V.
may range from 2.7V to 3.3V.
®
).