器件名称: FX621
功能描述: Low-Power Subscriber Private Metering (SPM) Detector
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简 介:CML Semiconductor Products
PRODUCT INFORMATION
FX621
Features/Applications Meets 12kHz and 16kHz SPM Specifications Low-Power CMOS [ 3.5 – 5 Volt Operation ] Tone Follower and SPM Packet Detection Modes
Low-Power Subscriber Private Metering (SPM) Detector
Publication D/621/2 June 1991 Provisional Issue
Adjustable Input Gain PABX, Payphone and Telephone Applications General-Purpose Tone Detection Crystal Oscillator Stability
XTAL V DD
XTAL/CLOCK 4.433619 MHz OSCILLATOR
V SS 4.433619 MHz
V BIAS 3 or 4 AMP INPUT ( – ) – AMP INPUT (+) + 2 "SYSTEM GAIN SET" AMPLIFIER
1
SYSTEM SELECT 12/16 kHz
FREQUENCY DIVIDERS
1 MODE SELECT
FX621
AMP OUTPUT (GAIN SET)
554.203 kHz or 738.937 kHz LEVEL DETECTOR FREQUENCY WINDOW DETECTOR
OUTPUT RESET
DETECTOR INPUT
COUNTERS AND OUTPUT LOGIC OUTPUT
PULSE LENGTH TIME
SPACE LENGTH TIME
Fig.1 Internal Block Diagram
Brief Description
The FX621 is a single-chip, low-power CMOS tone detector designed for use in both PABX and general payphone applications for Subscriber Private Metering. The Decode and Not-Decode band edges are accurately defined by the use of an external 4.433619MHz crystal. Operation to either of the 12kHz or 16kHz SPM systems is pin programmable, with system amplitude sensitivities and pulse-length timing being provided by the use of external components. The FX621 has 2 pin-selectable modes of operation: 1) Tone Follower Mode. A logic “0” is output whenever a tone of the correct frequency and length is detected. 2) S……