LT5504EMS8 Linear Technology, LT5504EMS8 Datasheet - Page 5

• Manufacturer Part Number: LT5504EMS8
• Description: IC MEASURING RECEIVER RF 8-MSOP
• Manufacturer: Linear Technology

Specifications of LT5504EMS8

• Function: RF Measuring Receiver
• Frequency: 800MHz ~ 2.7GHz
• Rf Type: CDMA, GSM, TDMA, WCDMA
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Pin Count: 8
• Screening Level: Industrial
• Package Type: MSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

PI FU CTIO S
V
tied together at the part as close as possible, and should
be decoupled using 1000pF capacitors.
RF
RF
GND (Pin 4): Ground Pin.
BLOCK DIAGRA
APPLICATIO S I FOR ATIO
The LT5504 consists of the following sections: RF/IF
limiters, limiting mixer, RF/IF detectors, LO buffer ampli-
fier, 3rd-order integrated low pass filter (LPF), output
interface and bias circuitry.
An RF signal ranging from 800MHz to 2.7GHz is detected
by the RF and IF detectors using a proprietary technique.
The down-converted IF signal is band limited by the on-
chip LPF, reducing broadband noise, and thus an ultrawide
dynamic range signal can be measured. The RF measuring
receiver is essentially a logarithmic voltage detector. The
measured output voltage is directly proportional to the RF
signal voltage. An internal temperature compensation
circuit results in a highly temperature-stable output volt-
age.
CC
+
–
U
(Pins 1, 8 ): Power Supply Pins. These pins must be
(Pin 2): Positive RF Input Pin.
(Pin 3): Negative RF Input Pin.
U
RF
RF
U
U
–
+
2
3
U
W
LIMITER
RF
W
DET
LIMITING
BUFFER
MIXER
V
LO
LO
CC
1
6
U
LPF
DET
EN (Pin 5): Enable Pin. The on/off threshold voltage
is about V
0.6 • V
input voltage is less than 0.4 • V
LO (Pin 6): Local Oscillator Input Pin.
V
RF Limiter
The differential input impedance of the RF limiter is shown
in Figure 1. A 1:1 input transformer can be used to achieve
50Ω broadband matching with an 82Ω shunt resistor (R1)
at the inputs as shown in Figure 5.
The 1:1 RF input transformer can also be replaced with a
narrow band single-ended-to-differential conversion cir-
cuit using three discrete elements as shown in Figure 2.
Their nominal values are listed in Table 1. Due to the
parasitics of the PCB, these values may require adjust-
ment.
LIMITER
OUT
IF
GND
V
CC
8
4
(Pin 7): Output Pin.
CC
, the circuit is completely turned on. When the
DET
+
CC
/2. When the input voltage is higher than
• • •
LIMITER
ENABLE
IF
EN
5
DET
CC
5504 BD
, the circuit is turned off.
7
V
OUT
LT5504
5
5504f