lt5525 Linear Technology Corporation, lt5525 Datasheet - Page 7

• Manufacturer Part Number: lt5525
• Description: High Linearity, Low Power Downconverting Mixer
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
The LT5525 consists of a double-balanced mixer, RF
balun, RF buffer amplifier, high speed limiting LO buffer
and bias/enable circuits. The IC has been optimized for
downconverter applications with RF input signals from
0.8GHz to 2.5GHz and LO signals from 500MHz to 3GHz.
With proper matching, the IF output can be operated at
frequencies from 0.1MHz to 1GHz. Operation over a
wider frequency range is possible, though with reduced
performance.
The RF, LO and IF ports are all differential, though the RF
and LO ports are internally matched to 50Ω for single-
ended drive. The LT5525 is characterized and production
tested using single-ended RF and LO inputs. Low side or
high side LO injection can be used.
TEST CIRCUITS
U
U
1900MHz
REF DES
C1
C2
C3
C4
C8
L2, L3
T2
RF
IN
W
900MHz INPUT MATCHING:
C1: 3.9pF
OPTIONAL
1760MHz
C1
LO
IN
VALUE
0.01µF
150nH
100pF
1.2pF
1µF
4:1
—
U
EN
1
2
3
4
Figure 1. Test Schematic
17
NC
RF
RF –
NC
+
SM-22
NC
EN
0402
0402
0402
0402
0603
1608
SIZE
16
5
V
LO
CC1
LT5525
6
+
15
C2
V
LO –
CC2
RF Input Port
The mixer’s RF input, shown in Figure 2, consists of an
integrated balun and a high linearity differential amplifier.
The primary terminals of the balun are connected to the
RF
ary side of the balun is internally connected to the amplifier’s
differential inputs.
For single-ended operation, the RF
the RF
ground the RF
RF source has a DC voltage present, then a coupling
capacitor must be used in series with the RF input pin.
Otherwise, excessive DC current could damage the pri-
mary winding of the balun.
14
PART NUMBER
Frequency Dependent
AVX 04023C103JAT
AVX 04025A1R2BAT
AVX 04025A101JAT
Taiyo Yuden LMK107BJ105MA
Toko LL1608-FSR15J
M/A-COM ETC4-1-2
7
+
NC
NC
and RF
GND
GND
13
8
IF –
IF
–
+
pin becomes the RF input. It is also possible to
12
11
10
9
–
pins (Pins 2 and 3, respectively). The second-
C8
–
pin and drive the RF
C3
L3
L2
0.062"
C4
0.018"
0.018"
1
2
3
5526 F01
ER = 4.4
T2
V
CC
+
+
5
4
pin is grounded and
pin, if desired. If the
RF
GND
DC
GND
IF
140MHz
OUT
LT5525
7
5525f