ADF7901 Datasheet, PDF (1/12 Pages) Analog Devices – High Performance ISM Band ASK/FSK Transmitter IC

Preliminary Technical Data
FEATURES
Single chip low power UHF transmitter
369.5 MHz to 395.9 MHz frequency operation using
Fractional-N
PLL and fully integrated VCO
3.0 V supply voltage
Data rates supported < 2.5 kbps
Low current consumption 26 mA at 12 dBm
Output at 384 MHz
Power-down mode (< 1 µA)
24-Lead TSSOP package
GENERAL DESCRIPTION
The ADF7901 is a low power OOK/FSK UHF transmitter
designed for use in RF Remote Control Devices. The device
High Performance ISM Band
ASK/FSK Transmitter IC
ADF7901
is capable of Frequency Shift Keying (FSK) modulation on
8 different channels, selectable by 3 external control lines. OOK
modulation is performed by modulating the PA control line.
The on-chip VCO operates at 2 × the output frequency. The
divide by 2 at the output of the VCO reduces the amount of PA
feedthrough. As a result of this, OOK modulation depths of
greater than 50 dB are easily achievable.
The FSK_ADJ and ASK_ADJ resistors can be adjusted in the
system to optimize output power, for each modulation scheme.
An additional 1.5 dB of output power is provided for the lower
bank of channels to adjust for antenna performance. The CE
line allows the transmitter to be powered down completely. In
this mode, the leakage current is typically 0.1 µA.
FUNCTIONAL BLOCK DIAGRAM
OSC1
OSC2
DV_DD
TXDATA
R=1
PDF
CHARGE
PUMP
FSK
÷ FRACTIONAL N
SIGMA-DELTA
CHANNEL SELECT
VCO
PA_EN
C_REG2
C_VCO
V_DD
RF_OUT
PA
RF_GND
LDO
REGULATOR
#1
LDO
REGULATOR
#2
C_REG1
C_REG2
RS ET
CE
D_GND
FSK1 FSK2 FSK3
OOK_SEL
RSET_FSK
Figure 1.
RSET_OOK
Rev. PrD
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