7

LT5525

5525f

TEST CIRCUITS

REF DES

VALUE

SIZE

PART NUMBER

C1

—

0402

Frequency Dependent

C2

0.01µF

0402

AVX 04023C103JAT

C3

1.2pF

0402

AVX 04025A1R2BAT

C4

100pF

0402

AVX 04025A101JAT

C8

1µF

0603

Taiyo Yuden LMK107BJ105MA

L2, L3

150nH

1608

Toko LL1608-FSR15J

T2

4:1

SM-22

M/A-COM ETC4-1-2

Figure 1. Test Schematic

140MHz

5526 F01

16

15

14

13

56

7

8

12

11

10

9

NC

NC

GND

GND

EN

EN

RF

+

RF–

LO

+

LO–

NC

17

1

2

3

4

NC

NC

IF

+

IF–

1900MHz

1760MHz

15

4

3

2

C4

L3

L2

C3

C2

C8

LT5525

RF

GND

GND

DC

ER = 4.4

0.018"

0.018"

0.062"

900MHz INPUT MATCHING:

C1: 3.9pF

C1

OPTIONAL

T2

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.

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

ary side of the balun is internally connected to the amplifier’s

differential inputs.

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.