IF Transceiver Subsystem
28-Lead SSOP Package
TDMA FM/FSK Systems
The AD6402 is a complete transceiver subsystem for use in
high bit rate radio systems employing FM or FSK modulation.
It is optimized for use in time domain multiple access (TDMA)
systems with communications rates of approximately 1 MBPS.
The AD6402 integrates key functions, including VCOs and a
low drop-out voltage regulator. The AD6402 operates directly
from an unregulated battery supply of 3.1 V to 4.5 V and pro-
vides a regulated voltage output which can be used for VCO
supply regulation on a companion RF chip such as the AD6401.
The AD6402 transceiver consists of a mixer, integrated IF
bandpass filter, IF limiter with RSSI detection, VCO, PLL
demodulator and a low dropout voltage regulator. On receive, it
downconverts an IF signal in the 110 MHz range to a second
IF frequency, this frequency being determined by the demodu-
lator reference divide ratios. It then filters, amplifies, and de-
modulates this signal. The AD6402 provides a filtered baseband
FUNCTIONAL BLOCK DIAGRAM
VREG VBATT SLREF CTL1...3
data output. On transmit, it accepts a Gaussian Frequency Shift
Keying (GFSK) baseband signal, low-pass filters the signal if
required using the on-chip op amp and modulates the IF VCO
by varying the bias voltage on an off-chip varactor diode used in
the tank circuit.
The AD6402 has multiple power-down modes to maximize
battery life. It operates over a temperature range of –25°C to
+85°C and is packaged in a JEDEC standard 28-lead small-
shrink outline (SSOP) surface-mount package.
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use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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