U2795B.pdf 데이터시트 (총 14 페이지) - 파일 다운로드 U2795B 데이타시트 다운로드

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Features
Supply-voltage Range: 2.7 V to 5.5 V
Single-ended Output, no Balun Required
Single-ended Input for RF and LO
Excellent Isolation Characteristics
Power-down Mode
IP3 and Compression Point Programmable
2.5-GHz Operating Frequency
Benefits
Reduced System Costs as only Few External Component (no Balun) are Required
Small Package
Very Low Current Consumption
Easy to Use
Electrostatic sensitive device.
Observe precautions for handling.
Description
The U2795B is a 2.5-GHz mixer for WLAN and RF telecommunications equipment,
e.g., DECT and PCN. The IC is manufactured using Atmel's advanced bipolar technol-
ogy. A double-balanced approach was chosen to assure good isolation characteristics
and a minimum of spurious products. The input and output are single-ended, and their
characteristics are programmable. No output transformer or balun is required.
Figure 1. Block Diagram
2
RFi
VS
R2
5 IFo
3
P
R1
VH
4 So
VR
VH Voltage
regulator
8 PD
2.5-GHz
Double-
balanced
Mixer
U2795B
7
LO i
61
GND
VS
Rev. 4654A–CELL–01/03
1

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Pin Configuration
Figure 2. Pinning
VS 1
RF 2
P3
SO 4
Pin Description
Pin Symbol
1 VS
2 RFi
3P
4 SO
5 IFO
6 GND
7 LOi
8 PU
Function
Supply voltage
RF input
Progamming port IP3, CP
Output symmetry
IF output
Ground
LO input
Power-up
8 PU
7 LOi
6 GND
5 IFO
2 U2795B
4654A–CELL–01/03

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U2795B
Functional Description
Supply Voltage
The IC is designed for a supply-voltage range of 2.7 V to 5.5 V. As the IC is internally
stabilized, the performance of the circuit is nearly independent of the supply voltage.
Input Impedance
The input impedance, ZRFi, is about 700 W with an additional capacitive component. This
condition provides the best noise figure in combination with a matching network.
3rd Order Intercept Point The voltage divider, RP/R1, determinates both the input and output intercept point, IIP3
(IP3)
and OIP3. If the value of RP is infinite, the maximum value of IIP3 reachs about -4 dBm.
The IP3/RP characteristics are shown in Figure 3 and Figure 4.
Output Impedance and
Intercept Point
The output impedance is shown in Figure 11. Both low output impedance and a high
intercept point are defined to a high value of RP.
Current Consumption, IS
Depending on the chosen input and output conditions of the IC, the current consump-
tion,IS, is between 4 mA and 10 mA. The current consumption in dependence of Rp is
shown in Figure 6.
Power-up
Output Symmetry
This feature provides extended battery lifetime. If this function is not used, Pin 8 has to
be connected to VS (Pin 1).
The symmetry of the load current can be matched and thus optimized for a given load
impedance.
Absolute Maximum Ratings
Parameters
Supply voltage
Input voltage
Junction temperature
Storage-temperature range
Symbol
VS
VI
Tj
Tstg
Value
6
0 to VS
125
-40 to +125
Unit
V
V
°C
°C
Thermal Resistance
Parameters
Junction ambient SO8
Symbol
RthJA
Value
175
Unit
K/W
Operating Range
Parameters
Supply-voltage range
Ambient-temperature range
Symbol
VS
Tamb
Value
2.7 to 5.5
-40 to +85
Unit
V
°C
4654A–CELL–01/03
3