U2781B Datasheet, PDF (2/10 Pages) TEMIC Semiconductors – Frequency Synthesizer

U2781B
Functional Description
The IC is controlled by a 3-wire bus with Clock, Data and
Enable inputs for programming the scaling factors of the
programmable counter, the reference counter and the
prescaler.
A TCXO can be connected to the oscillator input (OSCi)
as an alternative solution to the common crystal reference
oscillator. In that case, the oscillator output (OSCo)
should be left open.
The charge pump-output operates as switched current
sources. The characteristics of the phase-locked loop can
be determinated by the external low-pass filter.
The phase characteristic of the phase detector is convert-
ible and thus matchable to different frequency/ tuning
voltage characteristics.
Pin Description
Osci 1
NC 2
Osco 3
V_SCP 4
V_{S 5}
CP 6
20 NC
19 NC
18 NC
17 Mo
16 NC
15 PS
GND 7
LDo 8
NC 9
14 Enable
13 Data
12 NC
RFi 10
11 Clock
14775
Figure 2. Pinning
Pin Symbol
Function
1
Osci Oscillator input
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₂
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₃
Osco Oscillator output
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₄
V_SCP Charge-pump supply voltage
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₅
V_s Supply voltage
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₆
CP Charge-pump output
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₇
GND Ground
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 8
LDo Lock-detector output
9
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₀
RFi VCO input
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₁
Clock 3-wire bus Clock
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₂
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₃
Data 3-wire bus Data
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₄
Enable 3-wire bus Enable
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₅
PS Phase select input
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 16
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ¹⁷
Mo Monitor output for f_p and f_r
18
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁₉
NC Not connected
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₂₀
NC Not connected
Absolute Maximum Ratings
ÁÁÁÁÁÁÁÁ_SROOBPCSÁÁÁÁÁÁÁÁ_{uhtFuhssopaccsarisiipranilleg}ÁÁÁÁÁÁÁÁ_{lnllgp-yaaepesutt-euvoopttl}ÁÁÁÁÁÁÁÁ_{etorruemlviomctnoatupppgl}ÁÁÁÁÁÁÁÁ_{itetnupeairptunagutvpte}ÁÁÁÁÁÁÁÁ_{utovurvlotetolva}ÁÁÁÁÁÁÁÁ_{tlgoateglatgeaP}ÁÁÁÁÁÁÁÁ_egaeraÁÁÁÁÁÁÁÁ^metÁÁÁÁÁÁÁÁ^ers ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ^SVVVVyVVTVm_OBOSÁÁÁÁÁÁÁÁ_sRPCsUtSs^b_gSFccPS^o_oiÁÁÁÁÁÁÁÁ^l ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ_{––4V0}ÁÁÁÁÁÁÁÁ_{0.1Va3t1666.lo5S}^utÁÁÁÁÁÁÁÁ_oe1265ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ^U_°ÁÁÁÁÁÁÁÁ_VVVVVVVnCit ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
2 (10)
TELEFUNKEN Semiconductors
Rev. A3, 26-Nov-97