RF3196 View Datasheet(PDF) - RF Micro Devices
Part Name
Description
Manufacturer
RF3196 Datasheet PDF : 16 Pages
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RF3196
The power control functionality provides 50dB continuous control range and 70dB total control range, using a DAC compatible
analog voltage input referred to as VRAMP. The timing of the control signals is important for maintaining transient performance
and superior isolation between the bursts. To ensure that the part ramps up properly, a timing diagram is provided below in Fig-
ure 4. It is important that ramping begins at least 2us after TXEN goes high. An offset voltage of 0.26V provides the greatest
dynamic range for the best transient performance.
VBATT
2.9 V to 4.2 V
2.5V
BandSel
0 to 5 dBm
RF Drive
> 1.8V
TX_Enable
Vramp starts 2us
after Tx_Enable
0.26 to 2.1 V
Vramp ends 2us
before Tx_Enable
VRAMP
Power On Sequence:
Apply VBATT
Apply Band Select
Apply RF drive
Apply TX_Enable & VRAMP in unison
The Power Down sequence is in opposite order of the Power On Sequence
Figure 4. RF3196 Timing Diagram
As described in the above figure, VBATT is applied first to provide bias to the silicon control chip. Then the RF drive is applied.
Finally, when TX_ENABLE is high, the VRAMP signal is held at constant 0.26V, and 2uS later, VRAMP begins to ramp up.
The shape of VRAMP is important for maintaining the switching transients. The basic shape of the ramping function should be
the first 90° of a raised sine function. This is shown in Equation 1 where A is the desired peak power in mW, B is the minimum
output power of the power amplifier in mW, K determines the duration of the ramp, and t is time. The down-ramp function uses
the same equation except a cosine function is used in the place of the sine function. The exponent “n” determines the steep-
ness of the ramp and is typically set to 5.
POUT(mW) = (A – B) ⋅ ( sin (Kt))n + B
(Eq. 1)
The value of K is calculated using Equation 2.
K = 2-----⋅---t-π-r--a---m----p
(Eq. 2)
The Ramp synthesis tool provided by RFMD generates the ramp profiles automatically. It will generate ramps for all power lev-
els and output the waveform for 8, 10, and 12 bit DACs in decimal, voltage, or hex formats.
Rev A2 DS071207
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
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