MOTOROLA = SEMICONDUCTOR sox TECHNICAL DATA MC2831A LOW POWER FM TRANSMITTER SYSTEM The MC2831A is a one-chip FM transmitter subsystem designed for cordless telephone and FM communication equipment. It includes a Microphone Amplifier, Pilot Tone Oscillator, Voltage Controlled Oscillator and Battery Monitor. @ Wide Range of Operating Supply Voltage (3.0 V-8.0 V) @ Low Drain Current (4.0 mA Typ Full Operation at Vcc = 4.0 V) Battery Checker (290 nA Typ at Vcc = 4.0 V) @ Low Number of External Parts Required LOW POWER FM TRANSMITTER SYSTEM SILICON MONOLITHIC INTEGRATED CIRCUIT Users Must Comply with Local Regulations on R.F. Transmission (FCC, DOT, PT.T., etc) FUNCTIONAL BLOCK DIAGRAM 16 1 P SUFFIX PLASTIC PACKAGE CASE 648 1 16 RF Osc ke 16 = 264 Variable 45 e Reactance D SUFFIX PLASTIC PACKAGE CASE 751B (SO-16) PIN ASSIGNMENTS e 3 poe 14 Vec a 4 -~ I | Variable Mic Reactance HB Output RF Amp Veer td : Osc E 12 Decoupling 55] A Modulator RF Battery input 14) Output Checker " Veco [4] [t3] Gnd Vec Tone so Mic Amp Input Ha\Veci Mic Amp Batter i y Output 1 Checker Tone 7 10} LED Switch H i) Tone 9] Osc Output coil ORDERING INFORMATION Temperature Device Range Package MC2831AD $O-16 30C to +75C MC2831AP Plastic DIP MOTOROLA LINEAR/INTERFACE ICs DEVICE DATA 8-46MC2831A MAXIMUM RATINGS (T, = 25C, unless otherwise noted) Rating Symbol Value Unit Power Supply Voltage Vcc 10 Vdc Operating Supply Voltage Range Vcc 3.0 to 8.0 Vde Battery Checker Output Sink Current ILED 26 mA Junction Temperature Ty +150 C Operating Ambient Temperature Range Ta -30to +75 C Storage Temperature Range Tstg -65 to + 150 c ELECTRICAL CHARACTERISTICS (Vcc) = 4.0 Vdc, Vec2 = 4.0 Vde, Ta = 25C, unless otherwise noted) Characteristic Symbol Pin Min Typ Max Unit Drain Current icc1 12 150 290 420 nA Drain Current lec2 4 2.2 3.6 6.5 mA BATTERY CHECKER Threshold Voltage (LED Off On) VTB " 1.0 1.2 1.4 Vde Output Saturation Voltage VOSAT 10 - 0.15 0.5 Vde (Pin 11 = OV, Pin 10 Sink Current = 5.0 mA) MIC AMPLIFIER Voltage Gain, Closed Loop Ay 5,6 27 30 33 dB (Vin = 1.0 MVims. fin = 1.0 kHz), Output DC Voltage Vode 6 1.14 1.4 1.7 Vdc Output Swing (Vin = 30 MVrms, fin = 1.0 kHz} Vop-p 6 0.8 1.2 1.6 Vp-p Total Harmonic Distortion THD 6 _ 0.7 _ % (Vg = 31 MVems, fin = 1.0 kHz) PILOT TONE OSCILLATOR (250 2 LOADING) Output AF Voltage (fo = 5.0 kHz) VAFO 8 _ 50 _ MVims Output DC Voltage Vode 8 _ 1.4 _ Vde Total Harmonic Distortion THD 8 _ 1.8 5.0 % (fo = 5.0 kHz, Var = 150 MVime} Tone Switch Threshold _ 7 11 1.4 17 Vde FM MODULATOR (120 0 LOADING) Output RF Voltage (fp = 16.6 MHz) VAFO 14 40 | mms Output DC Voltage Vode 14 1.3 _ Vde Modulation Sensitivity (Note 1) SEN 3,14 6.0 10 18 Hz.mVdce (Vin = 1.0V + 0.2 V) Maximum Deviation (Note 1) Fdev 3,14 +25 =5.0 212.5 kHz (Vin = OV to +2.0V) RF Frequency Range _ 14 _ _ 60 MHz Note 1. Modulation sensitivity and maximum deviation are measured at 49.815 MHz, which is the third harmonic of the crystat frequency. MOTOROLA LINEAR/INTERFACE ICs DEVICE DATA 8-47MC2831A FIGURE 1 TEST CIRCUIT 4.7 wH MC2831A aT T Mic Amp In ow 68k 220 k Mic Amp Out o 4 so 0) 16.605 MHz Yec1 Battery Checker In Tone Switch LED 0.047 L1 Toko America Tone Output Vcec2 7PA Type 126AN 6708X i 20 mH - Osc Coil FIGURE 2 SINGLE CHIP FM VHF TRANSMITTER AT 49.7 MHz 4.7 pH _ 16.5667 MHz ) L 1 16 56 pF 0.0047 <2] 15 | ] 51 pF = ra 100 pF 5.0 pF 100k {4 La 1s pF | RF Output 39 pF 49.7 MHz ra T 730 pF = - 30 dBm 0.00154 13 - = 22st 0.33 pH 0.47 zH 1 3.0k - 15 | 3 z y } Dynamic Microphone = 10k 1 PLE a 0.001 J Vec = 3.0 V to B.0V NOTES: $1 is a normally closed push button type switch. The crystal used is fundamental mode, calibrated for parallel resonance with a 32 pF load. The 49.7 MHz output is generated in the output buffer, which generates useful harmonics to 60 MHz. The network on the output at Pin 14 provides output tuning and imped- ance matching to 50 !) at 49.7 MHz. Harmonics are suppressed by more than 25 dB. Battery checker circuit (Pins 10, 11) is not used in this application. All capacitors in microfarads, inductors in Henries and resistors in Ohms, unless otherwise specified. MOTOROLA LINEAR/INTERFACE ICs DEVICE DATA 8-48