Linear Technology DC 1710A-D Quick Start Manual

1

DESCRIPTION

Demonstration Circuit 1710A-D is a dual 2.3GHz to

4.5GHz high dynamic range downconverting mixer
featuring the LTC®5593. The LTC5593 is part of a
family of dual-channel high dynamic range, high
gain downconverting mixers covering the 600MHz
to 4.5GHz frequency range.

The Demo Circuit

1710A-D and the LTC5593 are optimized for

2.3GHz to 4.5GHz RF applications. The LO fre­quency must fall within the 2.1GHz to 4.2GHz
range for optimum performance.

A typical appli­cation is a LTE or WiMAX multichannel or diversity
receiver with a 2.3GHz to 2.7GHz RF input.

The LTC5593 is designed for 3.3V operation, how­ever the IF amplifiers can be powered by 5V for the
highest P1dB. A low current mode is provided for
power savings, and each of the mixer channels
has independent shutdown control.

The LTC5593’s high conversion gain and high dy­namic range enable the use of lossy IF filters in
high-selective receiver designs, while minimizing
the total solution cost, board space and system­level variation.

High Dynamic Range Dual Downconverting Mixer Family

DEMO # IC PART # RF RANGE LO RANGE

DC1710A-A LTC5590 600MHz-1.7GHz 700MHz-1.5GHz
DC1710A-B LTC5591 1.3GHz-2.3GHz 1.4GHz-2.1GHz
DC1710A-C LTC5592 1.6GHz-2.7GHz 1.7GHz-2.5GHz

DC1710A-D LTC5593 2.3GHz-4.5GHz 2.1GHz-4.2GHz

Design files for this circuit board are available. Call
the LTC factory.

, LT, LTC, LTM, Linear Technology and the Linear Logo are registered trade­marks of Linear Technology Corporation. All other trademarks are the property of
their respective owners.

DEMO CIRCUIT 1710A-

D

QUICK START GUIDE

LTC559

3

Dual 2.3GHz to 4.5

GHz

HIGH DYNAMIC RANGE

DOWNCONVERTING MIXER

LTC5593

3

2

APPLICATIONS NOTE

For detailed applications information, please refer
to the LTC5593 datasheet.

ABSOLUTE MAXIMUM RATINGS

NOTE.

Stresses beyond Absolute Maximum Ratings may cause
permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.

Supply Voltage (VCC)

.............................................4.0V

IF Supply Voltage (VCCIF)

......................................

5.5V

Enable Voltage (ENA, ENB)

.............

-0.3V to V

CC

+ 0.3V

Bias Adjust Voltage (IFBA, IFBB)

......

-0.3V to V

CC

+ 0.3V

Power Select Voltage (ISEL)

.............

-0.3V to V

CC

+ 0.3V

LO Input Power (1GHz to 3GHz)

...........................

9dBm

RFA, RFB Input Power (1GHz to 3GHz)

................

15dBm

Operating Temperature Range

.................

-40°C to 105°C

SUPPLY VOLTAGE RAMPING

Fast ramping of the supply voltage can cause a
current glitch in the internal ESD protection circuits.
Depending on the supply inductance, this could
result in a supply voltage transient that exceeds the
maximum rating. A supply voltage ramp time of
greater than 1ms is recommended.

Do not clip powered test leads directly onto the
demonstration circuit’s VCC and VCCIF turrets.

Instead, make all necessary connections with
power supplies turned off, then increase to operat­ing voltage.

ENABLE FUNCTION

The LTC5593’s two mixer channels can be inde­pendently enabled or disabled. When the Enable
voltage (ENA or ENB) is logic high (>2.5V), the cor­responding mixer channel is enabled. When the
Enable voltage is logic low (<0.3V), the mixer
channel is disabled. The voltages at the enable
pins should never fall below -0.3V or exceed the
power supply voltage by more than 0.3V. The En-

able pins must be pulled high or low. If left floating,
the on/off state of the IC will be indeterminate. A
logic table for the Enable control (ENA, ENB) is
shown in Table 1.

TABLE 1. ENABLE CONTROL LOGIC TABLE

ENA, ENB MIXER CHANNEL STATE

Low Disabled

High Enabled

LOW CURRENT MODE

The LTC5593 features a low current mode, which
allows the flexibility to choose a 37% total power
saving when lower RF performance is acceptable.
When the ISEL voltage is logic low (<0.3V), both
mixer channels operate at nominal DC current and
best performance. When the ISEL voltage is logic
high (>2.5V), both mixer channels are in low cur­rent mode and operate with reduced performance.
The ISEL voltage should never fall below -0.3V or
exceed the power supply voltage by more than

0.3V. The ISEL pin must be pulled low or high. If
left floating, the operating current state of the IC will
be indeterminate. A logic table for ISEL is shown in
Table 2.

TABLE 2. ISEL LOGIC TABLE

ISEL OPERATING MODE

Low Normal current, best performance

High Low current, reduced performance

RF INPUTS

Demonstration Circuit 1710A-D’s RF inputs of
channel A and channel B are identical.

For the RF
inputs to be matched, the appropriate LO sig­nal must be applied.

The RF inputs’ impedance is
dependent on LO frequency, but the Demonstra­tion Circuit 1710A-D’s RF inputs are well matched
to 50Ω from 2.3GHz to 4.5GHz, with better than
12dB return loss, when a 2.1GHz to 4.2GHz LO
signal is applied.

LO INPUTS

Demonstration Circuit 1710A-D’s LO input is well
matched to 50

Ω

from 2.1GHz to 3.4GHz, with bet-

LTC5593

3

3

ter than 12dB return loss. For LO frequency from

3.4GHz to 3.8GHz, the LO port can be well
matched by using C2 = 0.6pF and L4 = 10nH.

The LTC5593’s LO amplifiers are optimized for the

2.1GHz to 4.2GHz LO frequency range. LO fre­quencies above and below this frequency range
may be used with degraded performance. The LO
input is always 50Ω-matched when VCC is applied
to the chip, even when one or both of the channels
is disabled. The nominal LO input level is 0dBm.
The LO input power range is between -4dBm and
6dBm.

IF OUTPUT

Demonstration Circuit 1710A-D features single­ended, 50Ω-matched IF outputs for 190MHz. The
channel A and the channel B IF outputs are identi­cal, and the impedance matching is realized with a
bandpass topology using IF.

Demonstration Circuit 1710A-D can be easily re­configured for other IF frequencies by simply re­placing inductors L1A, L2A, L1B and L2B. Inductor
values for several common IF frequencies are pre­sented in Table 3. External load resistor, R2A and
R2B, can be used to improve impedance matching
if desired.

TABLE 3. INDUCTOR VALUES vs. IF FREQUENCIES

IF FREQUENCY (MHz) L1A, L2A, L1B, L2B (nH)

140 270
190 150
240 100
300 56
380 33
470 22