STB4395 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
STB4395 Datasheet PDF : 16 Pages
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STB4395
5 - POWER SUPPLIES
5.1 - Supplies
The chip operates from a power supply of 3.0 to
5.5 Volts. All interface circuits to the baseband
chips are operated between these supplies.
Six on-chip regulators are included on-chip which
provide to all parts of the circuit separate regulated
voltage supplies of -2.85 ±0.15 Volts relative to the
top rail for the RF circuitry, the IF circuitry, the digital
circuitry and for the three VCO’s.
The chip can be operated in 3 modes, power down,
receive and transmit. Power down is activated tak-
ing the Pin EN to VN . To transfer to the receive
mode, NTXEN is taken to VP.
The built-in regulators can be by-passed ,if so
required.
5.2 - Ground Plane Connections
The chip has been designed to be decoupled to the
positive supply, VP , at many points. Therefore it is
strongly recommended that the chip be mounted
on a board with a ground plane connected to VP.
Because the base band chip is specified relative to
a negative ground, it is further recommended that
the board used is a 4 layer board with both a
positive, VP , and negative ground plane VN . This
has the additional advantage of providing good
high frequency decoupling between supplies.
The question as to whether to call VP or VN ground
depends on which external equipment is con-
nected. For testing the baseband section, this is
VN ; for testing the radio chip, this is VP. In a
product, this will depend on the application.
For clarity all voltages specified in this document
will be specified with respect to the supply, VP or
VN , that the voltage normally tracks with when the
supply is varied.
6 - ELECTRICAL CHARACTERISTICS
Symbol
Parameter
Min. Typ. Max. Unit
VN Power Supply Voltage (unregulated)
-3
-5.5 V
VREG Power Supply bypassing Internal Regulators (this is also interface supply) -2.7
-3
V
IRX Receive Mode
32
40 mA
ITX Transmit Mode
68
80 mA
IQ Standby/Power Down
20 µA
7 - TIMING INFORMATION
7.1 - Turn on-off Times
Times are relative to the NTXEN transition (high to low for receive to transmit and low to high for transmit
to receive).
Symbol
tON
tRAMPON
tTXRX
Parameter
Turn-on Time From standby to receive
PA Power Ramp up to reach -3dB of final power
Switchover Time Transmit to Receive (LNA/first mixer active)
Min. Typ. Max. Unit
10
µs
27.78 µs
27.78 µs
7.2 - Channel Select Timing
PRGCLK must be high before NPRGEN goes low to programme the synthesizer.
Figure 2 : Timing of Serial Programming Data
NPRGEN
Orde r of NPRGEN &PRGD unimportant
P RGCLK
PRGD
P ROGRAM
CODE
Code changes on Rising Edge ofNPRGEN
Note that although a new program code is implemented on the rising edge of the NPRGEN, the transmitted
power level is delayed until at the start of the next burst of transmission. In order to change transmit power
during a conversation, the required power code must be serially loaded with the power change instruction.
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