TX4915 PTC | Alldatasheet

Document overview

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Technical content

Features

‹ Output frequency range: 300 – 960 MHz ‹ Supply voltage range: 2.2 – 3.6 V ‹ Low current consumption with power down capability ‹ On-chip VCO with integrated PLL (÷ 64/128) dual modulus prescaler ‹ Out-of-lock inhibit circuit ‹ SSOP-16 package (0.64 mm pitch)

Applications

‹ Wireless mouse ‹ Car alarm and home security systems ‹ Remote control systems Block Diagram 7 8 TXENOSC OUT OSC IN NC VSS2 VCC2RES RES OSC VCO Prescaler ÷ 64/128 DO PFD and CP 3 4 5 6 10 91516 14 13 12 11 VSS TXOUT VSS1 VCC1 MODIN AMP LDSW LD BIAS

Package and Pin Assignment SSOP-16 (0.64mm pitch) Symbol Dimensions in mm Dimensions in inches A1 0.10 — 0.25 0.004 — 0.010 C 0.19 — 0.25 0.007 — 0.010 D 4.80 — 5.00 0.189 — 0.197 E 5.80 — 6.20 0.228 — 0.244 E1 3.80 — 4.00 0.150 — 0.157 L 0.40 — 1.27 0.016 — 0.050 θ 0° — 8° 0° — 8° OSCIN OSCOUT TXEN VSS TXOUT VSS1 VCC1 MODIN SW LD DO RES RESB VREFP VSS2 VCC2 TX4915 HiMARK

1O S C I N This pin is connected directly to the base of the reference oscillator transistor. The reference oscillator uses a modified Colpitts configuration. 2 OSCOUT This pin is connected directly to the em itter of the reference oscillator transistor. 3T X E N Transmitter enable control (TXEN = low = power down mode; TXEN = high = nor- mal operation mode). 4 VSS Ground connection for the transmit output amplifier. 5 TXOUT Transmitter output. This pin is an open collector output and requires a pull-up inductor for bias/matching and a tapped capacitor network for matching. 6 VSS1 Ground connection for the transmit driver amplifier. 7 VCC1 Nominal supply voltage for the transmit driver amplifier. 8M O D I N ASK modulation input. An external resistor, RMODIN, connected from the MODIN pin to supply voltage is used to bias the transmit amplifier chain. 9 VCC2 Nominal supply voltage for the VCO and PLL circuitry. 10 VSS2 Ground connection for the PLL circuitry. 11 NC No connection.

12 RES

Differential open collector VCO outputs.

13 RES

Output of the charge pump. An R-C network from this pin to ground is used to establish the PLL bandwidth. The DO pin is internally connected to the tuning volt- age input of the VCO thru a 4 KΩ series resistor. 15 LD Lock detector output. This pin is used to set the threshold of the lock detect circuitry which enables or disables the transmit amplifier. A shunt capacitor should be used to set an R-C time constant with the on-chip series 1 KΩ resistor. The time constant should be set to approximately 15 times the reference period. 16 SW Prescaler modulus control input (SW = high = ÷ 64; SW = low = ÷ 128).