Texas Instruments TRF3701, Руководство пользователя

Страница: 10 / 29

Purpose
1-2
1.1 Purpose
The TRF3701/TRF3702 evaluation module (EVM) is intended for the
evaluation of the TRF3701 and TRF3702 direct launch quadrature modulator.
Unless otherwise stated, the functionality described in this manual applies to
both the TRF3701 and TRF3702 devices.
1.2 EVM Circuit Overview
The EVM comes configured for differential I/Q input signals via four SMA
connectors as shown in the schematic and Table 1 - 1.
The EVM has an option for differential I/Q input signals via the two THS4503
op amps as shown in the schematic and Table 1 - 1. The THS4503 (U2, U3)
provides single-ended/differential inputs and outputs in an 8-pin package. The
device has a unity gain bandwidth of 370 MHz, a slew rate of 2800 V/
µ
s, and
a IMD3 –95 dBc at 30 MHz. The outputs from U2 and U3 are applied to the
TRF3701/TRF3702 quadrature modulator IC.
The I signals are connected to J4 (I+) and J8 (I - ), respectively. The Q signals
are connected to J5 (Q+) and J11 (Q - ), respectively. The LO signal is fed to
J2 and the SMA connector J3 is used to monitor the output signal from the
quadrature modulator (U1).
The quadrature modulator requires a supply voltage of 5 V / 145 mA from a
regulated power supply. Both the amplifiers (U2, U3) and the
TRF3701/TRF3702 are powered from external power supplies connected to
connector J1. The op amp supply voltage must not exceed
±
7.5 V.
The TRF3701/TRF3702 quadrature modulator requires a dc common mode
bias voltage (3.7 Vdc) on all four input pins. Power supply connectors J6 and
J13 accepts these voltages from an external power supply.
1.3 Power Requirements
The EVM has three dc-power supply connectors: J1 accepts
±
7 V for op amp
supply and a V
CC
of 5 V for the TRF3701/TRF3702. J6 accepts the
VCM (3.7 V) common-mode bias voltage for the TRF3701/TRF3702. J13
accepts the VCM (3.7 V) input signal common-mode bias when using op amps
U2 and U3.
Voltage Limits
Exceeding the
±
7.5 V maximum may damage the THS4503 op amp.
Exceeding 5.6 V may damage the TRF3701/2