Linear Technology LT5557 Quick Start Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1131A
DESCRIPTION
Demonstration circuit 1131A is optimized for evalua-
tion of the LT5557 active downconverting mixer with
transformer-based IF output matching. Its RF input
and LO input ports are internally matched to 50Ω Ω Ω Ω ,
from 1.6 to 2.3GHz, and from 1 to 5GHz, respectively.
The IF output is 50Ω Ω Ω Ω matched to 240MHz using an L-C
bandpass network followed by an 8:1 transformer.
The LT5557 active mixer is optimized for high linearity,
wide dynamic range downconverter applications. The
IC includes a high-speed differential LO buffer amplifier
driving a double-balanced mixer.
grated transformers on the RF and LO inputs provide
single-ended 50Ω Ω Ω Ω interfaces. The differential IF output
Table 1. Typical Demonstration Circuit Performance Summary (V
1710MHz, P = -3dBm, IF output measured at 240MHz, unless otherwise noted. Test circuit shown in Figure 2.)
LO
PARAMETER
Supply Voltage
Total Supply Current
Maximum Shutdown Current
RF Input Frequency Range
LO Input Frequency Range
IF Output Frequency Range
LO Input Power
Conversion Gain
rd
Input 3 Order Intercept
Single-Sideband Noise Figure
LO to RF Leakage
LO to IF Leakage
RF to LO isolation
RF to IF isolation
2RF-2LO Output Spurious Product
(f = f ± f /2)
RF LO IF
3RF-3LO Output Spurious Product
(f = f ± f /3)
RF LO IF
Input 1dB Compression
HIGH SIGNAL LEVEL DOWNCONVERTING MIXER
Broadband, inte-
CONDITION
EN = High (> 2.7V)
EN = Low (< 0.3V)
Return Loss > 12dB
Return Loss > 10dB
Return Loss > 10dB
2 RF tones, -6dBm/tone, ∆f = 1MHz
F = 1830MHz, P = -6dBm, f
RF RF
F = 1790MHz, P = -6dBm, f
RF RF
allows convenient interfacing to differential IF filters
and amplifiers, or is easily matched to drive a single-
ended 50Ω Ω Ω Ω load, with or without an external trans-
former.
The LT5557's high level of integration minimizes the
total solution cost, board space and system-level varia-
tion.
Design files for this circuit board are available. Call
the LTC factory.
, LT, LTC, and LM are registered trademarks of Linear Technology Corporation.
= 3.3V, EN = High, T = 25°C, f
CC A
= 240MHz
IF
= 240MHz
IF
LT5557
= 1950MHz, P = -6dBm, f
RF RF
VALUE
2.9 to 3.9V
81.6mA
100µA
1600 to 2300MHz
1000 to 4200MHz
220 to 260MHz
-8 to 2dBm
2.9dB
24.7dBm
11.7dB
< -45dBm
< -42dBm
> 42dB
> 41dB
-53dBc
-70dBc
8.8dBm
=
LO
1