Audio ICs PLL frequency synthesizer for tuners BU2615S / BU2615FS The BU2615 PLL frequency synthesizers work up through the FM band. Featuring low radiation noise, low power consumption, and highly sensitive built-in RF amps, they support an IF count function. Applications Tuners (Mini components, radio cassette players, radio equipment, etc.) Features 1) Built-in high-speed prescaler can divide 130MHzVCO. 2) Basic oscillation of 75kHz keeps unnecessary radiation noise to a low level. 3) Low current dissipation (during operation: 4mA, PLL OFF: 100µA) 4) In addition to the standard FM and AM, also offers the following 7 frequencies: 25kHz, 12.5kHz, 6.25kHz, 3.125kHz, 5kHz, 3kHz, and 1kHz. 5) Counter for measurement of intermediate frequencies. 6) Unlock detection 7) Seven output ports (open drain). The BU2614, with three output ports, is also available. 8) Serial data input (CE, CK, DA) Absolute maximum ratings (Ta = 25C) Recommended operating power supply voltage 125 Audio ICs Block diagram Pin assignments 126 BU2615S / BU2615FS Audio ICs BU2615S / BU2615FS Pin descriptions 127 Audio ICs Electrical characteristics (unless otherwise noted, Ta = 25C, VDD1 = VDD2 = 5.0V) 128 BU2615S / BU2615FS Audio ICs BU2615S / BU2615FS Explanation of the data (1) Division data: For D0 through D15 (When S = 1, use D4 through D15.) (2) (3) (4) (5) (6) (7) (8) (9) CT: Frequency measurement beginning data 1: Beginning of measurement 0: Internal counter is reset, IFIN is pulldown. Output port control data: P0, P1, P2, P3, P4, P5, P6 1: Open drain output ON (P5 is LO) 0: Open drain output OFF (P5 is HI) R0, R1, R2, standard frequency data S: switch between FMIN and AMIN 0: FMIN 1: AMIN PS: If this bit is set to ON while AMIN is selected, swallow counter division is possible. CH: If this bit set to ON, output port P5 goes to phase comparison output. 0: P5 1: PD2 GT: Frequency measurement time and unlock detection ON / OFF TS: Test data. Input(0). 129 Audio ICs Input data format 130 BU2615S / BU2615FS Audio ICs BU2615S / BU2615FS 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, input pulldown and the counter are reset. Measuring time (gate pulse) is selected (16ms / 32ms) 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 How the unlock detection circuit operates 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. Explanation of output data 131 Audio ICs How the frequency counter and unlock detection circuit operate (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. 132 BU2615S / BU2615FS Audio ICs BU2615S / BU2615FS External dimensions (Units: mm) 133