Philips TDA8735, TDA8735T Datasheet

INTEGRATED CIRCUITS

TDA8735

PLL frequency synthesizer

Product specification	September 1994
File under Integrated Circuits, IC01

Philips Semiconductors

Philips Semiconductors	Product specification
PLL frequency synthesizer	TDA8735

FEATURES

∙Complete 30 MHz single-chip tuning system

∙Loop amplifier included

∙2-level current amplifier (charge pump) for adjusting the loop gain

∙A powerful digital memory phase detector

∙Programmable reference frequencies of 1 kHz, 10 kHz or 25 kHz

∙I2C-bus interface

∙Programmable address select input

∙Software controlled switch output.

APPLICATIONS

∙Satellite sound receiver

∙Radio receiver: LW, MW and SW.

QUICK REFERENCE DATA

GENERAL DESCRIPTION

The TDA8735 is a single-chip PLL synthesizer designed for satellite receivers. The device can be set to two different addresses which can be used in applications where independently tuned VCOs are required.

To adapt to different frequency accuracy, 3 reference frequencies are selectable via the I2C-bus. The charge pump current can be set to 2 values with a ratio of 1 : 100 via the I2C-bus.

A programmable switch (open collector) is integrated to enable mode or normal switching, or other types of application.

SYMBOL		PARAMETER			CONDITIONS	MIN.		TYP.	MAX.	UNIT
VCC1	supply voltage (pin 3)					4.5		5.0	5.5	V
VCC2	supply voltage (pin 16)					VCC1		8.5	12	V
ICC1	supply current (pin 3)				outputs unloaded	12		20	28	mA
ICC2	supply current (pin 16)				outputs unloaded	0.2		0.5	1	mA
fi(max)	maximum input frequency					30		−	−	MHz
fi(min)	minimum input frequency					−		−	512	kHz
Vi(rms)	input voltage (RMS value)					30		−	500	mV
Ptot	total power dissipation					−		0.14	−	W
Tamb	operating ambient temperature					−30		−	+85	°C
ORDERING INFORMATION
TYPE					PACKAGE
NUMBER	NAME			DESCRIPTION					VERSION
TDA8735	DIP16		plastic dual in-line package; 16 leads (300 mil)						SOT38-1
TDA8735T	SO16		plastic small outline package; 16 leads; body width 3.9 mm						SOT109-1

September 1994

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Philips Semiconductors

Product specification

PLL frequency synthesizer

TDA8735

BLOCK DIAGRAM

	Block diagram.
	Fig.1
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Philips Semiconductors	Product specification
PLL frequency synthesizer	TDA8735

PINNING

SYMBOL	PIN	DESCRIPTION
XTAL1	1	reference oscillator output
XTAL2	2	reference oscillator input
VCC1	3	supply voltage 1
VEE	4	ground
n.c.	5	not connected
DEC	6	prescaler decoupling
VCOFI	7	VCO input frequency
BS	8	band switch output
n.c.	9	not connected
SDA	10	serial data input (I2C-bus)
SCL	11	serial clock input (I2C-bus)
AS	12	address select input (I2C-bus)
n.c.	13	not connected
LOOPI	14	tuning voltage amplifier input
LOOPO	15	external loop filter output
VCC2	16	supply voltage 2

FUNCTIONAL DESCRIPTION

The TDA8735 contains the following parts and facilities:

∙Input amplifier VCO-signal.

∙A prescaler with the divisors 3 : 4 and a 2-bit programmable swallow counter.

∙A 13-bit programmable counter.

∙A digital memory phase detector.

∙A reference frequency channel comprised of a 4 MHz crystal oscillator followed by a reference counter; the reference frequency can be 1 kHz, 10 kHz or 25 kHz and is applied to the digital memory phase detector.

∙An I2C-bus interface with data latches and control logic; the I2C-bus is intended for communication between microcontrollers and different ICs or modules. Detailed information on the I2C-bus specification is available on request.

∙A software-controlled switch output.

∙A programmable current amplifier (charge pump) which consists of a 5 μA and a 500 μA current source, this allows adjustment of loop gain, thus providing high-current high-speed tuning and low current-stable

tuning. The output at the loop amplifier can deliver a tuning voltage of up to 10.5 V (VCC2 − 1.5 V).

Fig.2 Pin configuration.

Controls

The TDA8735 is controlled via the 2-wire I2C-bus. As slave receiver for programming there is one module address, a logic 0 (R/W bit), a subaddress byte and four data bytes. The subaddress determines which one of the four data bytes is transmitted first. The module address contains a programmable address bit (D1) which with address select input AS (pin 12) makes it possible to operate two TDA8735 in one system.

The auto increment facility of the I2C-bus allows programming of the TDA8735 within one transmission (address + subaddress + 4 data bytes).

The TDA8735 can also be partially programmed. Transmission must then be ended by a stop condition.

The bit organization of the 4 data bytes is illustrated in Fig.3 and is described below.

The divider number is defined by 15-bit words, bits S0 to S14. To calculate the lock frequency, the divider number has to be multiplied by the selected reference frequency.

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Philips Semiconductors				Product specification
PLL frequency synthesizer				TDA8735
Table 1 Divider number setting.
	ON		DIVIDER NUMBER SETTING	INPUT
0			(S0 + S1) × 21 .... + S13 × 213 + S14 × 214	ON

Where the minimum divider ratio is: 26 = 64 to 215 − 1 = 32761.

Table 2 Bit CP (used to control the charge pump;

	DB0: D0).
CP		CURRENT
0		LOW
1		HIGH

Table 3 Bits REF1 and REF2 (used to set the reference frequency applied to the phase detector;

DB2: D7 and D6).

	REF1	REF2	FREQUENCY
			(kHz)
	0	0	1
	0	1	10
	1	0	25
	1	1	0

Table 4 Bit OPAMP (used to control the switch in the tuning voltage amplifier output circuitry; DB2: D4).

OPAMP	SWITCH
1	on
0	off

Table 5 Bit BS (used to control the open-collector switch

	output; DB2: D2).
BS		SWITCH OUTPUT
1		sink current
0		floating

The data byte DB3 must be set to 0....0. It is also used for test purposes (see Fig.3).

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