U2781B
Frequency Synthesizer
Description
The programmable frequency synthesizer IC U2781B for
µP-controlled
application is realized with TEMIC’s
advanced UHF process which is very suitable for
combinations of fast ECL logic and low-current I
2
L logic.
The benefits are high input sensitivity in connection with
low power consumption and therefore small
packages (SSO20). This makes the device a perfect
choice for cordless phones and handheld cellular radio
sets up to 1.1 GHz.
Electrostatic sensitive device.
Observe precautions for handling.
Features
D
D
D
D
D
D
D
D
D
Very low current consumption (typ. 3 V/ 5 mA)
Supply voltage range: 2.7 to 5.5 V
Max. input frequency: 1.1 GHz
Programmable prescaler 64/ 65 or 128/ 129
Controlled by 3-wire bus with f
clock
up to 500 kHz
Status output for PLL lock/ unlock condition
Very fast phase detector
SSO20 package
ESD protection in accordance with MIL-STD. 883
method 3015 class 2
Benefits
D
Very low current consumption extends talk time
D
Few external components and SSO package save costs
and space
Block Diagram
Osci
Osco
VS
GND
1
3
5
7
1-bit latch
load control
18-bit
shift register
Phase
detector
Charge
pump
15-bit latch
Oscillator
14-bit
reference counter
Mo
17
LDo
8
VSCP
4
CP
6
Clock
11
Data
13
Enable
14
18-bit latch
Prescaler
64/65
128/129
7-bit
swallow
counter
11-bit
main
counter
15
PS
RFi
10
93 7785 e
Figure 1. Block diagram
Ordering Information
Extended Type Number
U2781B-AFS
U2781B-AFSG3
Package
SS020
SS020
Remarks
Rail, MOQ 830 pcs
Tape and reel, MOQ 4000 pcs
TELEFUNKEN Semiconductors
Rev. A3, 26-Nov-97
1 (10)
TEMIC [ TEMIC SEMICONDUCTORS ]
