TELEFUNKEN Semiconductors
U2891B
2.5 GHz Quadrature Up-Converter
Description
The U2891B is a silicon monolithic IC made with TELE-
FUNKEN鈥檚 advanced UHF process. The IC consists of a
500 MHz I/Q quadrature modulator and a 2.5 GHz mixer.
Both parts can be connected via an external filter in order
to suppress harmonics and spurious products. The device
features 3 V operation, a low current consumption and
furthermore two separate power-down functions for mod-
ulator and mixer. The RF ports are single ended and the
device can be operated adjustment free, but for optimiza-
tion also two pins for phase adjustment are provided.
These features and the double conversion concept of
U2891B make this device perfectly suited for all digital
radio applications from 900 MHz up to 2.5 GHz (e.g.,
GSM, DCS 1800, JDC, PHP and WLAN).
D
Low power consumption: 25 mA / 3 V
(typical at 鈥? dBm output level)
D
2.5 GHz output frequency
D
Excellent sideband suppression by means of duty
cycle regeneration and 90擄 phase control
D
Separate power-down mode for modulator and mixer
D
Low LO input level: 鈥?10 dBm (typical)
D
LO and RF port 50-W single-ended
D
Extended talk time due to increased battery life
D
Few external components results in cost and board
space saving
D
Adjustment free, hence saves time and cost
D
One TX Platform for different systems
D
Reduced costs and space for battery (3-V operation)
Case:
SSO-24 package
Ordering Information:
U2891B-AFS, U2891B-AFSG3 (see page 5)
Block Diagram
Ad
ro
nic
C
om
po
ne
GND
24
GND
1
6
nt
s
S
IF
14
18
LP 2
IF
O
7
11
IF
i
50
Features
Benefits
BB
Ai
BB
Ai
2
3
LO 1
4
Gm
bH
PD
IF
PD
RF
V
S
13
Voltage
regulator
8, 21, 20
12
IF
i
9
LO2
15
S
RF
Lo - Reg.
f/2f
0擄
50
LO 1
5
90擄
枚
Control
RF
O
16
BB
Bi
BB
Bi
22
23
10,17
19
LP 1
94 8141 e
GND
Rev. A2: 04.10.1995
Advanced Information
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2
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4
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