Ordering number : EN4922C CMOS LSI LC72146, 72146M PLL Frequency Synthesizer for Electronic Tuning Overview Package Dimensions The LC72146 is a PLL frequency synthesizer LSI circuit for electronic tuning in car stereo systems. The LC72146 supports the construction of high-performance, multifunctional electronic tuning systems for the VHF MW, and LW bands. unit: mm 3067-DIP24S [LC72146] Features • High-speed programmable dividers for — 10 to 160 MHz on FMIN using pulse swallower — 0.5 to 40.0 MHz on AMIN using pulse swallower and direct division • General-purpose counters — HCTR for 0.4 to 25.0 MHz frequency measurement — LCTR for 10 to 500 kHz frequency measurement and 1.0 Hz to 20 × 103 kHz period measurement • Reference frequencies: Twelve selectable reference frequencies (4.5 or 7.2 MHz crystal) 1, 3, 5, 9, 10, 3.125, 6.25, 12.5, 25, 30, 50 and 100 kHz • Phase comparator — Insensitive band control — Unlock detection — Sub-charge pump for high-speed locking — Deadlock clear circuit • CCB input/output data interface • Power-on reset circuit • Built-in MOS transistor for a low-pass filter • Inputs/outputs (using five general-purpose input/output ports) — Maximum of seven inputs (max) — Maximum of seven outputs (max/four n-channel open-drain and three CMOS outputs) — Time-base output for clock (8 Hz) • Operating ranges — Supply voltage ..................................4.5 to 5.5 V — Opetating temperature ......................–40 to 85°C • Package — DIP24S, MFP24S SANYO: DIP24S unit: mm 3112-MFP24S [LC72146M] SANYO: MFP24S • CCB is a trademark of SANYO ELECTRIC CO., LTD. • CCB is SANYO’s original bus format and all the bus addresses are controlled by SANYO. SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN 73096HA (OT)/11095TH (OT) No. 4922-1/21 LC72146, 72146M Specifications Absolute Maximum Ratings at Ta = 25°C, VSS = 0 V Parameter Symbol Maximum supply voltage Maximum input voltage Maximum output voltage Maximum output current Allowable power dissipation Conditions Ratings Unit VDD max VDD –0.3 to +7.0 VIN1 max CE, CL, DI –0.3 to +7.0 V VIN2 max XIN, FMIN, AIN, AMIN, HCTR/I-6, LCTR/I-7, I/O-4, I/O-5 –0.3 to VDD + 0.3 V VIN3 max I/O-1 to I/O-3 –0.3 to +15 V VO1 max DO –0.3 to +7.0 V VO2 max XOUT, I/O-4, I/O-5, O-6, PD0, PF1, AIN –0.3 to VDD + 0.3 V V VO3 max I/O-1 to I/O-3, AOUT, O-7 IO1 max I/O-4, I/O-5, O-6, O-7 0 to 3.0 IO2 max DO, AOUT 0 to 6.0 mA IO3 max I/O-1 to I/O-3 0 to 10 mA Pd max –0.3 to +15 V mA DIP24S:Ta ≤ 85°C 350 mW MFP24S:Ta ≤ 85°C 220 mW Operating temperature Topr –40 to +85 °C Storage temperature Tstg –55 to +125 °C Allowable Operating Ranges at Ta = –40 to 85°C, VSS = 0 V Parameter Symbol Conditions min typ max Unit VDD1 VDD 4.5 VDD2 VDD: Serial data retain voltage 2.0 VIH1 CE, CL, DI, I/O-1 to I/O-3 2.2 6.5 V VIH2 I/O-4, I/O-5, HCTR/I-6 and LCTR/I-7 2.2 VDD V Input low-level voltage VIL1 CE, CL, DI and I/O-1 to I/O-5, HCTR/I-6, LCTR/I-7 0 0.8 V Input high-leve lvoltage VIH3 LCTR/I-7, Pulse wave*1 2.2 VDD V Input low-level voltage VIL2 LCTR/I-7, Pulse wave*1 0 0.8 V VO1 DO 0 6.5 V VO2 I/O-1 to I/O-3, AOUT, O-7 0 13 V fIN1 XIN; Sine wave, capacitive coupling 1.0 8.0 MHz fIN2 FMIN; Sine wave, capacitive coupling 10 160 MHz fIN3 AMIN; Sine wave, capacitive coupling 0.5 40 MHz fIN4 HCTR/I-6; Sine wave, capacitive coupling 0.4 25 MHz fIN5 LCTR/I-7; Sine wave, capacitive coupling 10 500 kHz fIN6 LCTR/I-7; Pulse wave, DC coupling*1 1.0 20 × 103 Hz Xtal XIN, XOUT; CI ≤ 120 Ω 4.0 8.0 VIN1 XIN Supply voltage Input high-level voltage Output voltage Input frequency Guaranteed oscillator element frequencies Input amplitude 5.5 V V MHz 200 1500 VIN2-1 FMIN; 50 ≤ f < 130 MHz*2 40 1500 mVrms mVrms VIN2-2 FMIN; 10 ≤ f < 50 MHz*2, 130 ≤ f 160 MHz 70 1500 mVrms VIN3-1 AMIN; 2 ≤ f < 25 MHz*2 40 1500 mVrms VIN3-2 AMIN; 25 ≤ f < 40 MHz*2 70 1500 mVrms VIN3-3 AMIN; 0.5 ≤ f < 2.5 MHz*2 40 1500 mVrms VIN3-4 AMIN; 2.5 ≤ f < 10 MHz*2 70 1500 mVrms VIN4-1 HCTR/I-6; 0.4 ≤ f < 25 MHz*3 40 1500 mVrms VIN4-2 HCTR/I-6; 8 ≤ f < 12 MHz*4 70 1500 mVrms VIN5-1 LCTR/I-7; 10 ≤ f < 400 kHz*3 40 1500 mVrms VIN5-2 LCTR/I-7; 400 ≤ f < 500 kHz*3 20 1500 mVrms VIN5-3 LCTR/I-7; 400 ≤ f < 500 kHz*4 70 1500 mVrms Data set up time tSU DI, CL*5 0.45 µS Data hold time tHD DI, CL*5 0.45 µS Continued on next page. No. 4922-2/21 LC72146, 72146M Continued from preceding page. Parameter Symbol Conditions min typ max Unit Clock low-level time tCL CL*5 0.45 µs Clock high-level time tCH CL*5 0.45 µs CE wait time tEL CE, CL*5 0.45 µs CE setup time tES CL, CE*5 0.45 µs CE hold time tEH CE, CL*5 0.45 Chip enable to data latch time tLC *5 Data output time tDC DO, CL; Depends on pull-up resistor Note: 1. 2. 3. 4. 5. µs 0.45 µs 0.2 µs Period measurement See the description of the structure of the programmable divider. With the CTC bit in the serial data set to 0 With the CTC bit in the serial data set to 1 See the description of the serial data timing. Electrical Characteristics at Ta = –40 to +85°C, VSS = 0 V Parameter Symbol Conditions min typ max Unit Rf1 XIN 1.0 mΩ Rf2 FMIN 500 kΩ Rf3 AMIN 500 kΩ Rf4 HCTR/I-6 250 kΩ Rf5 LCTR/I-7 250 kΩ Sub charge pump internal resistance R1S AIN 100 Ω Hysteresis VHIS CE, CL, DI, LCTR/I-7 0.1 VDD V Internal feedback resistance Output high-level voltage VOH1 VOH2 VOL1 VOL2 PD0, PD1, I/O-4, I/O-5, O-6 Input high-level current Input low-level current VDD – 0.5 V IO = 1 mA VDD – 1.0 V IO = 2 mA VDD – 2.0 AIN: IO = 1 mA PD0, PD1, I/O-4, I/O-5, O-6, O-7 VDD – 0.6 I/O-1 to I/O-3 V VDD – 0.3 V IO = 0.5 mA 0.5 V IO = 1 mA 1.0 V IO = 2 mA 2.0 V AIN: IO = 1 mA Output low-level voltage VOL3 IO = 0.5 mA 0.3 0.6 V IO = 1 mA 0.2 V IO = 2.5 mA 0.5 V IO = 5 mA 1.0 V IO = 9 mA 1.8 V VOL4 DO; IO = 5 mA 1.0 V VOL5 AOUT; IO = 1 mA, AIN = 1.3 V 0.5 V IIH1 CE, CL, DI; VI = 6.5 V 5.0 µA IIH2 I/O-1 to I/O-3; VI = 13 V 5.0 µA IIH3 I/O-4, I/O-5, HCTR/I-6, LCTR/I-7; VI = VDD 5.0 µA IIH4 XIN; VI = VDD 2.0 11 µA IIH5 FMIN, AMIN; VI = VDD 4.0 22 µA IIH6 HCTR/I-6, LCTR/I-7; VI = VDD 8.0 44 µA IIL1 CE, CL, DI; VI = 0 V 5.0 µA IIL2 I/O-1 to I/O5; VI = 0 V 5.0 µA IIL3 HCTR/I-6, LCTR/I-7; VI = 0 V 5.0 µA IIL4 XIN; VI = 0 V 2.0 11 µA IIL5 FMIN, AMIN; VI = 0 V 4.0 22 µA IIL6 HCTR/I-6, LCTR/I-7; VI = 0 V 8.0 44 µA Continued on next page. No. 4922-3/21 LC72146, 72146M Continued from preceding page. Parameter max Unit IOFF1 I/O-1 to I/O3, AOUT, O-7; VO = 13 V 5.0 µA IOFF2 DO; VO = 6.5 V 5.0 µA High-level three state off leakage current IOFFH PD0, PD1, AIN; VO = VDD 0.01 200 nA Lowh-level three state off leakage current IOFFL PD0, PD1, AIN; VO = 0 V 0.01 200 nA Output off leakage current Input cacitance Pull-down transistor on resistance Symbol Conditions min typ CIN FMIN Rpd1 FMIN 80 200 6 600 kΩ pF Rpd2 AMIN 80 200 600 kΩ 10 15 mA 0.5 1.5 mA 10 µA VDD; Xtal = 7.2 MHz, fIN2 = 160 MHz, IDD1 VIN2 = 70 mVrms, fIN4 = 25 MHz VIN4 = 40 mVrms Supply current IDD2 VDD; PLL inhibited, crystal oscillator running (Xtal = 7.2 MHz) IDD3 VDD; PLL inhibited, crystal oscillator stoped Pin Assignment Block Diagram No. 4922-4/21 LC72146, 72146M Pin Functions Number Symbol Type 24 1 XIN XOUT Xtal OSC 17 FMIN Local oscillator signal input Function Connection for crystal oscillator element (7.2 or 4.5 MHz) • Serial data input: FMIN is selected when DVS is set to 1. Input frequency range: 10 to 160 MHz • The signal is transmitted directly to the swallow counter • Divisor value range: 272 to 65535 • • • • • • • • Serial data input: AMIN is selected when DVS is set to 0. Serial data input: when SNS is set to 1. Input frequency range: 2 to 40 MHz The signal is transmitted directly to the swallow counter. Divisor value range: 272 to 65535 Serial data input: when SNS is set to 0. Input frequency range: 0.5 to 10 MHz The signal is transmitted directly to the 12-bit programmable divider. • Divisor value range: 4 to 4095 16 AMIN Local oscillator signal input 2 CE Chip enable • IThis pin must be set high to input serial data to the LC72146 DI pin or to output serial data from the DO pin. 4 CL Clock • Inputs the clock used for data synchronization when inputting serial data to the LC72146 DI pin or outputting serial data from the DO pin. 3 DI Input data • Input pin for serial data transmitted to the LC72146 from a controller. 5 DO Output data • Output pin for serial data transmitted from the LC72146 to a controller. 15 VDD Power supply 18 23 VDD Ground I/O-1 I/O-2 I/O-3 General-purpose I/O port 12 11 10 Equivalent circuit • The LC72146 power supply connection. A voltage between 4.5 and 5.5 volts must be supplied when the PLL circuit is used. • The power on reset circuit operates when power is first applied. • The LC72146 ground connection. • • • • General-purpose I/O ports Output mode circuit type: open drain Function after a power on reset: input port Can be set up to function as output ports by bits I/O-1 to I/O-3 in the serial data sent from the controller. Continued on next page. No. 4922-5/21 LC72146, 72146M Continued from preceding page. Number Symbol Type 9 8 I/O-4 I/O-5 General-purpose I/O port 7 O-6 Output port 6 20 19 21 22 14 O-7 PD0 PD1 AIN AOUT HCTR/I-6 Output port Charge pump output Function • • • • Equivalent circuit General-purpose I/O ports Output mode circuit type: complementary Function after a power on reset: input port Can be set up to function as output ports by bits I/O-4 and I/O-5 in the serial data sent from the controller. • The LC72146 latches the OUT6 bit in the serial data and outputs it from pin O-6. • The LC72146 latches the OUT7 bit in the serial data and outputs it from pin O-7. • Outputs a time base signal (8 Hz) when TBC is set to 1. • Function after a power on reset: open circuit • PLL charge pump output pin If the frequency generated by dividing the local oscillator frequency by N is higher than the reference frequency, a high level will be output from PD0, and if it is lower, a low level will be output. PD0 goes to the high-impedance state when the frequencies match. • PD1 operates identically. • Connections to the n-channel MOS transistor used for the PLL active low-pass filter. Connections for the • A high-speed locking circuit can be formed by using low-pass filter these pins with the built-in sub charge pump. transistor • See the item on the structure of the charge pump for details. General-purpose counter • HCTR is selected when CTS1 is set to 1. • Input frequency range: 0.4 to 25 MHz • The signal is passed through a divide-by-two circuit and then input to a general-purpose counter. This input also supports an integrating count function. • The result is output from the DO output pin starting with the MSB of the general-purpose counter. • See the item on the structure of the general-purpose counter for details. • When the H/I-6 bit in the serial data is set to 0: • This pin functions as an input port, and the value input is output from the DO pin. Continued on next page. No. 4922-6/21 LC72146, 72146M Continued from preceding page. Number Symbol Type Function • • • • • 13 LCTR/I-7 General-purpose counter • • • • • • • • Equivalent circuit LCTR is selected when CTS1 is set to 0. If the CTS0 bit in the serial data is set to 1: The circuit operates in frequency measurement mode. nput frequency range: 10 to 500 kHz The signal is directly transmitted to the general-purpose counter without passing through the divide-by-two circuit. If the CTS0 bit in the serial data is set to 0: The circuit operates in period measurement mode. nput frequency range: 1 Hz to 20 kHz The measurement period can be set to be either one or two periods of the input signal, and if two period measurement is selected, the input frequency range becomes 2 Hz to 40 kHz. The result is output from the DO output pin starting with the MSB of the general-purpose counter. See the item on the structure of the general-purpose counter for details. When the L/I-7 bit in the serial data is set to 0: This pin functions as an input port. The value input is output from the DO pin. No. 4922-7/21 LC72146, 72146M Functional Description Serial Data Input The LC72146/72146M operating parameters are initialized by two 40-bit data words on the serial data input, DI, as shown in Figure 1 and Figure 2 and Table 1. Figure 1 Input Data Word IN1 Figure 2 Input Data Word IN2 No. 4922-8/21 LC72146, 72146M Table 1 Input Data Functions No. Name Function Related bits Programmable divider ratio P15 is the MSB. The divider ratio, frequency range and lsb are determined by the setting of the DVS and SNS flags as shown in Table 2 and Table 3. P0 to P3 are ignored if P4 is the LSB. Table 2 Divider ratio settings (1) P0 to P15, DVS, SNS DVS SNS LSB 1 × P0 Divider ratio (N) 272 to 65535 0 1 P0 272 to 65535 0 0 P4 4 to 4095 Note: × = don’t care Table 3 Frequency range settings DVS SNS Input port 1 × FMIN Input frequency range (MHz) 0 1 AMIN 2 to 40 0 0 AMIN 0.5 to 10 10 to 160 Note: × = don’t care Sub-charge pump control Bits PDC0 and PDC1 control the charge pump state as shown in Table 4. The sub-charge pump is connected to the gate of the low-pass filter transistor. This can be used in conjunction with PD0 and PD1 (main charge pump) to build a fast locking PLL. Table 4 Charge pump state selection (2) PDC0, PDC1 PDC0 PDC1 0 × High impedance 1 1 Operating (operates continuously) 1 0 Operating (when PLL is unlocked) UL0, UL1, DLC Charge pump state Note: × = don’t care * See the “Charge Pump” on page 16 for details. Reference frequency select Bits R0 to R3 disable the PLL or select the reference frequency as shown in Table 5. Table 5 Reference frequency selection (3) R0 to R3 R3 R2 R1 R0 0 0 0 0 Reference frequency (kHz) 0 0 0 1 50 0 0 1 0 25 100 0 0 1 1 25 0 1 0 0 12.5 0 1 0 1 6.25 0 1 1 0 3.125 0 1 1 1 3.125 1 0 0 0 10 1 0 0 1 9 1 0 1 0 5 1 0 1 1 1 1 1 0 0 3 1 1 0 1 30 1 1 1 0 PLL inhibited and crystal oscillator stopped 1 1 1 1 PLL inhibited When the PLL is disabled, the programmable divider is stopped, AMIN and FMIN are pulled to ground, and the charge-pump outputs become high impedance. Continued on next page. No. 4922-9/21 LC72146, 72146M Continued from preceding page. No. Name Function Related bits DO and I/O5 output control data Bits ULD, DT0, DT1, IL0 and IL1 control the mode of outputs DO and I/O5 as shown in Table 6 and Table 7. Table 6 DO and I/O5 output flag selection ULD DT1 DT0 0 0 0 Unlock flag DO 0 0 1 Open 0 1 0 End-UC flag*1. 0 1 1 IN. See table 7. 1 0 0 Open 1 0 1 Open 1 1 0 End-UC flag 1 1 1 IN. See table 7. I/O5 OUT5 flag*2. Unlock flag*2. Note: *1. End-UC flags that general-purpose counter operation has finished. *2. Applicable only if I/O5 is set to be an output port. (4) ULD, DT0, DT1, IL0, IL1 OUT5, I/O1, I/O2, I/O5 Figure 3 DO output state Table 7 IN state selection IL1 IL0 0 0 Open IN state 0 1 I1 input 1 0 I2 input 1 1 DO goes low when I1 changes. Note: 1. If I/O1 or I/O2 is set to be an output port, IN becomes open. 2. DO does not go low when the crystal oscillator has stopped. [When reference frequencies are as these: R3 = R2 = R1 = 1; R0 = 0] (5) * Don’t care. Counter control Bits CTS0 and CTS1 select the counter input as shown in Table 8. Table 8 Counter input and measurement mode selection CTS0 Input Measurement mode 1 × HCTR Frequency 0 1 LCTR Frequency 0 0 LCTR Period CTS1 Note: × = don’t care CTS0, CTS1, CTE, GT0, GT1 (6) Bit CTE starts the counter when 1, and resets the counter, when 0. Bits GT0 and GT1 select the measurement time in frequency measurement mode or the number of periods to count in period measurement mode as shown in Table 9. H/I6, L/I7 Table 9 Measurement duration selection Frequency measurement CTP, CTC GT1 GT0 Measurement duration (ms) 0 0 4 0 1 8 1 0 32 1 1 64 Period measurement Wait time (ms) Cycles 3 to 4 1 7 to 8 2 When CTE is 0 the input is pulled down, and when CTP is 1 it is not. (Wait time: 1 to 2 ms.) CTP must be set to 1 at least 4 ms before CTE is set to 1. The input sensitivity can be reduced by setting CTC to 1. (Sensitivity: 10 to 30 mV rms) Continued on next page. No. 4922-10/21 LC72146, 72146M Continued from preceding page. No. Name Function Related bits Input/output port control Bits I/O1 to I/O5 set the direction of the ports. Each pin is an input when the corresponding bit is 0, and an output, when the bit is 1. All ports are set to be inputs after power-on reset. (7) I/O1 to I/O5 (8) OUT1 to OUT7 Output port data Bits OUT1 to OUT7 set the output values of the O-1 to O-7 output ports. Each output is open or high when the corresponding bit is 1, and low, when the bit is 0. A bit is ignored if the corresponding port is an input port or the unlock output. (9) H/I6, L/I7 Counter input control Bits H/I-6 and L/I-7 select the operation of the HCTR/I-6 and LCTR/I-7 pins. When H/I-6 is 0, HCTR/I-6 is an input port, and when H/I-6 is 1, HCTR/I-6 is the HCTR input. When L/I-7 is 0, LCTR/I-7 is an input port, and when L/I-7 is 1, LCTR/I-7 is the LCTR input. OUT1 to OUT5, ULD I/O1 to I/O5, ULD CTS0, CTS1 PLL unlock detect control Bits UL0 and UL1 select the phase error threshold and extension (øE) used to detect the PLL unlocked state as shown in Table 10 and Figure 4. When the phase error is greater than the selected error, the PLL unlock detector output goes low. Table 10 Unlock detection and extension selection (10) UL0, UL1 UL1 UL0 Phase error 0 0 Stopped Detector output Open 0 1 0 1 0 ±0.56 µs øE with 1 to 2 ms extension øE output 1 1 ±1.11 µs øE with 1 to 2 ms extension ULD, DT0, DT1 Figure 4 Phase-error extension (11) XS Crystal oscillator control Bit XS selects the oscillator frequency. When XS is 1, the frequency is 7.2 MHz, and when XS is 0, 4.5 MHz. 4.5 MHz is selected after power-on reset. Phase comparator control Bits DZ0 and DZ1 select the phase comparator insensitive band, or dead zone. Table 11 Insensitive band mode selection (12) DZ0, DZ1 DZ1 DZ0 0 0 Insensitive band (dead zone) mode DZA 0 1 DZB 1 0 DZC 1 1 DZD DZA is selected after power-on reset. (13) DLC Charge pump control Bit DLC controls the charge pump operation. When DLC is 1, the charge pump outputs are forced to low, and when DLC is 0, the charge pump operates normally. This feature can be useful to remove the PLL from a deadlock state. The PLL can deadlock if its VCO control voltage Vtune becomes 0 V, halting the VCO. Setting DLC to 1 sets Vtune to VCC, restarting the VCO. Normal operating mode is selected after power-on reset. (14) TBC An 8 Hz 40% duty clock time base signal can be output from pins 0 to 7 by setting TBC to 1. When TBC is 1 the OUT7 data will be invalid. TBC is set to 0 by the power-on reset. (15) TEST0 to TEST2 OUT7 Test data Bits TEST0 to TEST2 are used for in-factory device testing. Set them all to 0. They are set to zero after a power-on reset. No. 4922-11/21 LC72146, 72146M Serial Data Output The 40-bit data word output on DO has the format and functions as shown in Figure 5 and Table 12, respectively. Figure 5 Output Data Word Out Table 12 Input Data Functions No. Name Function Related bits (1) I1 to I7 Input port data Bits I-1 to I-7 reflect the data latched into each input port when the device changes to data output mode. I6 and I7 are zero when the corresponding port is a counter input. I1 to I5 correspond to the I/O1 to I/O5 ports, and I6 and I7, to the HCTR/I6 and LCTR/I7 inputs, respectively. I/O-1 to I/O-5, H/I-6, L/I-7 OUT1 to OUT5 (2) C0 to C19 Counter contents Bits C0 to C19 are the latched contents of the 20-bit binary counter. C19 is the msb. C0 is the lsb. CTS0, CTS1, CTE Serial Data Input/Output Mode Selection The LC72146/M use the CCB (computer control bus) serial data format. The first eight bits form the address, shown in Figure 6, used to select the mode of operation as shown in Table 13. Table 13 Serial Data Input/Output Mode Selection Input/output mode Address Function B0 B1 B2 B3 A0 A1 A2 A3 IN1 0 0 0 1 0 0 1 0 32-bit control data input IN2 1 0 0 1 0 0 1 0 32-bit control data input OUT 0 1 0 1 0 0 1 0 Output data. Data is output if the clock is active. No. 4922-12/21 LC72146, 72146M 1. Serial data input (IN1/IN2) 2. Serial data output (OUT) Note: 1. The data conversion time varies with the value of the pull-up resistor, since the DO pin is an n-channel open drain circuit. 2. The DO pin is normally open. Programmable Divider The configuration of the programmable divider is shown in Figure 7. The input mode selection is shown in Table 14, and the input sensitivity, in Table 15. Figure 7 Programmable Divider Table 14 Programmable Divider Selection DVS SNS Divisor setting (NO) Input frequency range 1 × 272 to 65535 10 to 160 MHz Input port FMIN 0 1 272 to 65535 2 to 40 MHz AMIN 0 0 4 to 4095 0.5 to 10 MHz AMIN Note: × = don’t care No. 4922-13/21 LC72146, 72146M Table 15 Input Sensitivity (Target Sensitivity) Minimum input sensitivity (f [MHz]) (A) FMIN (B) AMIN (C) AMIN 10 ≤ f < 50 50 ≤ f < 130 130 ≤ f < 160 70 mVrms 40 mVrms 70 mVrms 2 ≤ f < 25 25 ≤ f < 40 40 mVrms 70 mVrms 0.5 ≤ f < 2.5 2.5 ≤ f < 10 40 mVrms 70 mVrms — — CTC: Input sensitivity switching data. When CTC is 1 the input sensitivity is degraded.However, the actual values will be: HCTR → 30 to 40 mVrms (frequency: 10.7 MHz) LCTR → 10 to 15 mVrms (frequency: 450 kHz) CTP: The input pull-down resistor (when CTE is 0) can be disabled by setting CTP to 1. CTP must be set to 1 at least 4 ms before CTE is set to 1. CTP should be set to 0 if the counter is not used. When CTP is set to 1 wait time is reduced at 1 to 2 ms. The LC72146 includes a general-purpose 20-bit binary counter whose value can be read out from the DO pin, msb first. When using this counter for frequency measurement, one of four measurement times (4, 8, 32, or 64 ms) is selected by GT0 and GT1. The frequency input to either the HCTR or the LCTR pin can be measured by determining the number of pulses input to the counter during the measurement period. This counter can be used to measure the period of the signal input to the LCTR pin by determining how many cycles of a reference signal (900 kHz) are input to the counter during one or two periods of the LCTR pin signal. The counter is started by setting the serial data CTE bit to 1. While serial data is latched in the LC72146 when CE falls from high to low, input to the HCTR or the LCTR pin must be provided within the waiting period that follows CE being set low. Next, after the measurement completes, the value of the counter must be read out during the period that CTE is 1. (The general-purpose counter is reset when CTE is set to 0.) It should be emphasized here that the counter should be reset before measurement by setting CTE to 0. Also note that although the signal input to the LCTR pin is input to the counter directly, the signal input to the HCTR pin is divided by two internally before being input to the counter. Accordingly, the value of the counter will be 1/2 the actual frequency input to the HCTR pin. Figure 8 General-Purpose Counter No. 4922-14/21 LC72146, 72146M CTS1 CTS0 Input pin Measurement mode Frequency range Input sensitivity S1 1 — HCTR Frequency 0.4 to 25.0 MHz 40 mVrms* S2 0 1 LCTR Frequency 10 to 500 kHz 40 mVrms* S3 0 0 LCTR Period 1.0 to 20 × 103 Hz (pulse) Note: * CTC = 0: 40 mVrms CTC = 1: 70 mVrms However, the frequency ranges will be as follows when CTC is 1. HCTR: 8 to 12 MHz, LCTR: 400 to 500 kHz Frequency measurement mode GT1 GT0 0 0 4 0 1 8 Measurement time (ms) 1 0 32 1 1 64 Wait time (ms) Period measurement mode 3 to 4 One period 7 to 8 Two periods Integrating Count Note: CTE: 0 → • General-purpose counter reset • General-purpose counter start 1→ • Restarts on a new 1 setting In integrated count mode, the count value is accumulated in the general-purpose counter. Care is required to handle counter overflow. Counter values: 0H to FFFFFH (1,048,575) To implement the integrating count operation leave CTE set to 1. When the serial data (IN1) is transmitted again, the general-purpose counter will start to measure the input again and the result will be added to the count. No. 4922-15/21 LC72146, 72146M Charge Pump The charge pump configuration is shown in Figure 9. Figure 9 Charge Pump PDC1 PDC0 0 — PDS (sub-charge pump state) DLC PD1, PD0, PDS High impedance 0 Normal operation 1 Forced to low 1 1 Charge pump operates (normal operation) 1 0 Charge pump operates (when unlocked) When unlock is detected following a channel change, PDS (the sub-charge pump) operates. The value of R1 changes to R1M // R1S (R1S ≈ 100 Ω), as shown in Figure 10, decreasing the low-pass filter time-constant and accelerating PLL locking. Figure 10 Charge Pump Connections No. 4922-16/21 LC72146, 72146M The unlock detection data UL1 must be set to 1. The unlock detection range will be set to ±0.56 µs or ±1.11 µs. If a phase difference in excess of these values is detected the circuit will go to the unlock state and the sub-charge pump will operate. When the circuit approaches the lock state and the phase difference falls under the unlock detection range, the sub-charge pump operation will stop, i.e., the sub-charge pump will go to the high impedance state. Note: 1. Notes on the phase comparator dead zone DZ1 DZ0 Dead zone mode Charge pump Dead zone 0 0 DZA ON/ON – –0 s 0 1 DZB ON/ON –0 s 1 0 DZC OFF/OFF +0 s 1 1 DZD OFF/OFF + +0 s Cases where the charge pump is in the ON/ON state require special care during system design since the charge pump outputs correction pulses even when the PLL is locked and it is easy for the loop to become unstable. The following problems may occur in the ON/ON state. ① Sidebands may be generated by reference frequency leakage. ② Sidebands may be generated by low frequency leakage due to the correction pulse envelope. The settings that have a dead zone (the OFF/OFF settings) provide good loop stability, but it is hard to achieve a good S/N ratio with these settings. Inversely, the settings with no dead zone (the ON/ON settings) allow a high S/N ratio to be achieved but it is hard to achieve good loop stability with these settings. Therefore, it can be effective to select either the DZA or DXB setting, i.e., a setting which has no dead zone, when an S/N ratio of between 90 and 100 dB or higher is required in FM mode, or when the AM stereo pilot margin needs to be increased. However, in cases where such a high FM S/N ratio is not required and where an adequate AM stereo pilot margin can be achieved or AM stereo is not used, either the DZC or DZD setting, i.e., a setting which has a dead zone, should be selected. Dead Zone Definition The phase comparator compares fp with a reference frequency (fr) as shown in Figure 11. Figure 12 shows the characteristics of an ideal phase comparator, which outputs an output voltage (A) that is proportional to the phase difference ø. However, in an actual IC, a region (dead zone) in which minute phase differences cannot be detected occurs due to internal circuit delays and other factors. To implement an end product with a high S/N ration, the dead zone should be as small as possible. However, there are cases where a larger dead zone can make a popularly-priced model easier to use. This is because it is possible for RF leakage from the mixer to the VCO to modulate the VCO in popularly-priced models when a strong RF input is applied. When the dead zone is small an output that compensates for this problem is generated, and this output may itself modulate the VCO and generate beating with the RF frequency. No. 4922-17/21 LC72146, 72146M Figure 11 Figure 12 2. FMIN, AMIN, HCTR and LCTR These inputs should each be capacitively coupled using a 50 to 100 pF capacitor. Also, these capacitors should be mounted as close as possible to their respective inputs. 3. IF counting using HCTR or LCTR The LC72146 can perform IF count tuning when connected to an SD (station detector) signal from an IF IC. IF counting should start when the SD signal becomes active. Note on IF counting: The SD (station detect) signal must be used in conjunction with IF counting. When using the general-purpose counter for IF counting, be sure to determine whether or not there is an SD signal from the IF IC. The IF counter buffer should be turned on and IF counting performed only if there is an SD signal. Autosearch techniques that use only the IF counter are not recommended, since it is possible for IF buffer leakage output to cause incorrect stops at points where there is no station. 4. Using the DO pin In modes other than data output mode, the DO pin is also used for counter completion, unlock detection, and for checking for changes in the input pin. (In these cases the DO pin will change from the high to the low level.) The state of the input pin can be input to the controller directly through the DO pin. Pin States at Power On and Reset No. 4922-18/21 LC72146, 72146M Application System Example Note on Clock Time Base Usage A resistor of at least 100 kΩ must be used as the clock time base output pin (O-7) pull-up resistor. Also, the use of a Schmitt circuit is recommended in the controller (microprocessor) input circuit to prevent chattering. Forming a loop filter with the built-in low-pass filter transistor will also serve to prevent degradation of the VCO C/N characteristics. Since the grounding points for the clock time base output pin and the low-pass filter transistor are a common point within the IC, current fluctuations in the clock time base output pin must be kept to a minimum to limit influencing the low-pass filter. No. 4922-19/21 LC72146, 72146M Serial Data Timing No. 4922-20/21 LC72146, 72146M ■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. ■ Anyone purchasing any products described or contained herein for an above-mentioned use shall: ➀ Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: ➁ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. ■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of July, 1996. Specifications and information herein are subject to change without notice. No. 4925-21/21