Audio ICs
PLL frequency synthesizer for tuners
BU2624AF
The BU2624AF is a PLL frequency synthesizer IC designed for use in car stereos, high-fidelity audio systems, and CD
radio cassettes.
Featuring low current dissipation, low superfluous radiation, two frequency measurement counter systems, and two
phase comparison outputs, this chip is ideal for high-performance multi-band systems.
Applications
Car stereos, high-fidelity audio systems, radio cassettes,
receivers, and other frequency generating devices
Features
1) Built-in high-speed prescaler can divide
130MHzVCO.
2) Low current dissipation (during operation: 6.0mA,
PLL OFF: 300µA Typ.)
3) Seven standard frequencies: 50kHz, 25kHz,
12.5kHz, 10kHz, 9kHz, 5kHz, and 1kHz.
4) Two counters for intermediate frequency detection
5)
6)
7)
8)
9)
10)
Unlock detection circuit
Five output ports (open drain)
SD input port
Two charge pump outputs
Serial data input (CE, CK, DA)
Control of phase comparison output
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
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Audio ICs
Block diagram
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BU2624AF
Audio ICs
BU2624AF
Pin descriptions
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Audio ICs
Electrical characteristics (unless otherwise noted, Ta = 25C, VDD = 5.0V)
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BU2624AF
Audio ICs
BU2624AF
Circuit operation
Input data format
Output data format
CE output is set to LO.
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Audio ICs
BU2624AF
Explanation of the data
(1) Division data: For D0 through D15 (When S = 1, use
D4 through D15.)
(2)
(3)
(4)
CT: Frequency measurement beginning data 1:
Begins measurement.
0: Resets internal counter, IF1 and IF2 go to pul
down.
Output port control data: P0, P1, P2, P3, P4
PL PH: Control of charge pump output
PH = 0, PL = 0 PLL operation
PH = 0, PL = 1 PD1 PD2 LO level
PH = 1, PL = 0 PD1 PD2 HI level
PH = 1, PL = 1 PD1 PD2 LO level
(6) S: switch between FMIN and AMIN 0: FMIN
1: AMIN
(7) PS: If this bit is set to ON while AMIN is selected,
swallow counter division is possible.
(8) IFS: Selection between IF1 and IF2 during IF
count
0: IF1 1: IF2
(9) GT: Frequency measurement time and unlock
detection ON / OFF
(10) TS: Test data (0) is input
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(5)
R0, R1, R2, standard frequency data
Audio ICs
BU2624AF
Frequency counter
(1) Structure
(2) How the frequency counter operates
When control data CT equals 1, the 20-bit counter and the
amp go into operation. When CT equals 0, amp input goes
to pulldown and the counter is reset.
Measuring time (gate pulse) is selected (8 ms / 16 ms) on
the basis of control data GT.
When control data CT equals 0, the counter is reset.
(3) Explanation of output data
D0: LSB
D19: MSB
Unlock detection
When control data GT equals 1, or CT equals 1, the unlock detection circuit goes into operation for 8ms.
When CT equals 1, the unlock detection circuits stops
operating before the frequency counter gate pulse is
emitted.
When CT equals 0, or GT equals 0, the unlock detection
circuit is reset.
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Audio ICs
Frequency counter and unlock detection
(1) When CT = 1: Frequency count and unlock detection are carried out.
(2)
When CT = 0 and GT = 1: Only unlock detection is carried out.
Explanation of CD terminal
When frequency measurement or unlock detection is finished, the CD terminal goes to LO to indicate that the
count and unlock detection have finished.
It also synchronizes with CK to output counter data.
When the next data is input, it goes to HI.
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BU2624AF
Audio ICs
BU2624AF
External dimensions (Units: mm)
169
Appendix
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or
otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document use silicon as a basic material.
Products listed in this document are no antiradiation design.
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level of
reliability and the malfunction of with would directly endanger human life (such as medical instruments,
transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other
safety devices), please be sure to consult with our sales representative in advance.
About Export Control Order in Japan
Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control
Order in Japan.
In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause)
on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction.
Appendix1-Rev1.0
