LTC5588IPF-1#PBF Linear Technology, LTC5588IPF-1#PBF Datasheet - Page 24

• Manufacturer Part Number: LTC5588IPF-1#PBF
• Description: IC, MODULATOR, 200MHz To 6GHz, TQFN-24
• Manufacturer: Linear Technology

Specifications of LTC5588IPF-1#PBF

• Frequency Range: 200MHz To 6GHz
• Rf Type: GSM, LTE, WCDMA, WiMax
• Supply Voltage Range: 3.15V To 3.45V
• Rf Ic Case Style: TQFN
• No. Of Pins: 24
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LTC5588-1
APPLICATIONS INFORMATION
Linearity Optimization
The LINOPT pin (Pin 7) can be used to optimize the lin-
earity of the RF circuitry. Figure 6 shows the simplified
schematic of the LINOPT pin interface. The nominal DC
bias voltage of the LINOPT pin is 2.56V and the typical
voltage window to drive the LINOPT pin for optimum
linearity is 2V to 3.7V. Since its input impedance for EN =
High is about 150Ω, an external buffer may be required to
output a current in the range of –2mA to 8mA. The LINOPT
voltage for optimum linearity is a function of LO frequency,
temperature, supply voltage, baseband frequency, high
side or low side LO injection, process, signal bandwidth
and RF output level.
24
LINOPT
75Ω
EN
V
CC1
Figure 6. LINOPT Pin Interface
100Ω
Figure 7. EN Pin Interface
250Ω
V
CC1
100k
For zero-IF systems the spectral regrowth is typically
limited by the OIP2 performance. In that case, optimiz-
ing the LINOPT pin voltage may not improve the spectral
regrowth. The spectral regrowth for systems with an IF
(for example 140MHz) will be set by the OIP3 performance
and optimizing LINOPT voltage can improve the spectral
regrowth significantly (see Figure 13).
Enable Interface
Figure 7 shows a simplified schematic of the EN pin in-
terface. The voltage necessary to turn on the LTC5588-1
is 2V. To disable (shut down) the chip, the enable voltage
must be below 1V. If the EN pin is not connected, the chip
is enabled. This EN = High condition is assured by the
100k on-chip pull-up resistor.
55881 F07
55881 F06
INTERNAL
ENABLE
CIRCUIT
INTERNAL
ENABLE SIGNAL
55881fb