TSH690_01 STMICROELECTRONICS | Alldatasheet
Document overview
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Technical content
■ Supply voltage: 1.5V to 5V ■ >20 mW adjustable output power ■ 28 dB gain at 450 MHz ■ 21 dB gain at 900 MHz ■ 50 Ω matched input and output ■ Bias pin to adjust the amplification class ■ Power down
DESCRIPTION
The TSH690 is a wide band RF amplifier, de- signed in advanced bipolar process. At 450 MHz, it features 28dB gain and +13.5dBm (20 mW) out- put power at 3V. At 900 MHz, it features 23 dB gain and +15.5 dBm (35 mW) output power at 3V. The pin 8 allows a bias current adjust, setting the RF output level and the amplifier behaviour. It al- lows using the TSH690 from the linear A-class trough the AB-class to power-down mode. The TSH690 is suited to drive power amplifiers in cellular phones (GSM, TDMA) for which the ’turn-on time’ is controlled by a voltage ramp. The more than 20 mW output power makes the TSH690 dedicated as output stage for 433MHz and 868 MHz ISM transmitters.
APPLICATIONS
■ 433 MHz and 868 MHz ISM transmitters ■ Telemetering systems ■ Remote controls ■ Cordless Telephones ■ Driver for cellular phones ■ Wide band applications ORDER CODE D = Small Outline Package (SO) - also available in Tape & Reel (DT) PACKAGE PIN CONNECTIONS (top view) Part Number Temperature Range Package D TSH690ID -40, +85°C • D SO8 (Plastic Micropackage) TSH690 40MHz to 1GHz AMPLIFIER March 2001
Symbol Parameter Value Unit VCC1 , VCC2 , Vbias Supply Voltage & Bias Voltage 5.5 V RF in RF Input Power +10 dBm RF out RF Output Power +21 dBm Toper Operating Free Air Temperature Range -40 to +85 °C Tstg Storage Temperature Range -65 to +150 °C Symbol Parameter Value Unit VCC1 , VCC2 Supply Voltages 1.5 to 5 V Vbias Bias Voltage 0 to 5 V RF sr RF Signal Range 40 to 1000 MHz ESD SENSITIVE DEVICE Handling Precautions Required
ELECTRICAL CHARACTERISTICS AT 450 MHz Tamb = 25°C, VCC & Vbias = +2.7V, ZL = 50Ω, f = 450 MHz (unless otherwise specified) ELECTRICAL CHARACTERISTICS AT 900 MHz Tamb = 25°C, VCC & Vbias = +3V, ZL = 50Ω, f = 900 MHz (unless otherwise specified) Parameter1) 1. All min. and max. parameters of this table are garanteed by correlation with 900 MHz tests. Min. Typ. Max. Unit Power gain S21 (Pin = -20dBm) 20 23 30 dB Output Power 1dB Compression 8 12 dBm 3rd Order Intercept Point (f = 430MHz) 16 22 dBm Reverse Isolation S12 (f = 400MHz) -46 dB Input Return Loss S11 -10 -15 dB Noise Figure 4.5 dB Parameter 1. All min. and max. parameters of this table are garanteed by test. Min. Typ. Max. Unit Power gain S21 (Pin = -20dBm) 19 21 dB Output Power at 1dB compression point +12 +14.3 dBm Output power, Pin = -7 dBm +10 +11.7 dBm 3rd Order Intercept Point +25 dBm Reverse Isolation S12 -35 dB Input Return Loss S11 -14 dB Output Return Loss S22 -4.5 dB Noise figure 5.4 dB
SCATTERING PARAMETERS MEASUREMENT (Reference waves planes at package leads) TEST CONDITIONS VCC1 , VCC2 , Vbias = +2V, Pin = -40dBm, Tamb = 25°C Freq S11 S21 S12 S22 MHz Mag Ang Mag Ang Mag Ang Mag Ang
TEST CONDITIONS VCC1 , VCC2 , Vbias = +3V, Pin = -40dBm, Tamb = 25°C TEST CONDITIONS VCC1 , VCC2 , Vbias = +4V, Pin = -40dBm, Tamb = 25°C Freq S11 S21 S12 S22 MHz Mag Ang Mag Ang Mag Ang Mag Ang Freq S11 S21 S12 S22 MHz Mag Ang Mag Ang Mag Ang Mag Ang
The TSH690 is a 2 transistor stages amplifier run- ning within the 40MHz-1GHz frequency band fea- turing a gain of 28dB at 433MHz. The TSH690 is 50Ω input/output internally matched from 300MHz to 1000MHz. The open collector output requires an inductive load for the impedance matching and also to reach an output power of +13,5dBm at 3V and +18dBm at 4V. A bias control pin allows tun- ing of current consumption and amplification mode. As the matter of fact, when the bias pin is tied to the supply voltage, amplification is linear (Class A) while a lower voltage leads to a Class A-B amplifi- cation featuring a better efficiency. If the control voltage is grounded, the TSH690 is set in Pow- er-down mode without current consumption. MATCHING THE OUTPUT WITH L2 Within the 300-1000MHz band, although the cir- cuit is matched, the output return loss (S22) can be improved by adapting the value of the inductor L2. This inductor is connected between the RF output and V CC2 . L2 = 56 nH gives an output return loss of -19 dB at 450 MHz. L2 = 10 nH gives an output return loss of - 8 dB at 900 MHz. In a 433 or 450 MHz transmitter application, L1 and L2 can be optimized to reduce the second harmonic by choosing L1 = 33nH and L2 = 15nH. Below 300MHz, using the S-parameters matrix, specific input/output matching networks can be calculated to maximize electrical performances. DC BLOCKING Because input/output are respectively internal/ex- ternal biased, DC blocks (C1, C2) are recom- mended on both RF ports to guarantee a DC iso- lation from the next cells. Above 500MHz, 100pF is suggested whereas below, 1nF is better and far below (less than 100MHz), 10nF is prefered. BIASING The amplifier can operate in the range of 1.5V to 5V and offers a bias current adjust function (Vbias pin) which enables the trimming of the RF output power (AB class Amplifier) by tuning a series vari- able resistor (Rbias). When Vbias is wired to the Vcc rail, the current consumption is maximized getting the best linear- ity (A class Amplifier) whereas biasing to Ground, the IC is set in power down mode. For higher supply voltage than 4V to reach high output power, the serial resistor (R1) is strongly recommended to increase the efficiency of the amplifier and therefore reduce the thermal dissi- pation of the circuit. DECOUPLING As with any RF devices, the supply voltage decou- pling must be done carefully using a 1nF bypass capacitor (C3, C5) placed as close as possible to the device pins and could be also improved by adding a 150nH RF choke inductance (L1). Con- cerning the Vbias pin, a 10nF decoupling capaci- tor (C4) is recommended while placing on board is not critical. Note that Surface Mounted Devices (SMD) components are prefered for RF applica- tions due to the right behaviour in high frequencies while low inductor values (few 10nH) can be print- ed on board. Figure 4 : Demonstration board schematic
450 MHz operation (L2 = 56 nH)
100 200 300 400 500 600 700 800 900 1000 -25 -20 -15 -10 Freq (MHz ) S11 (dB) Vcc=Vbias @ Ta=+25°C L2=56nH (450MHz operation) 100 200 300 400 500 600 700 800 900 1000 -25 -20 -15 -10 Freq (MHz) S22 (dB) Vcc=Vbias @ Ta=+25°C L2=56nH (450MHz operation) -10 V CC = 4V V CC = 3V V CC = 2V TAMB = 25°C Freq = 450MHz S21(dB) VBIAS (V)
900 MHz operation (L2 = 10 nH)
OUTPUT POWER vs INPUT POWER 100 200 300 400 500 600 700 800 900 1000 Freq (MHz) Gain (dB) L2 =10nH (900MHz Operation) Vcc=Vbias=3V -40°C +25°C V +85°C 100 200 300 400 500 600 700 800 900 1000 -25 -20 -15 -10 Freq (MHz ) S11 (dB) Vcc=Vbias @ Ta=+25°C L2 =10nH (900MHz operation) 2V 3V 1 , 522 , 533 , 54 Vbias (V) P1dB (dBm) Ta=25°C L2 =10nH (900MHz operation) Vcc = 4V Vcc = 3V Vcc = 2V -20 -15 -10 -5 0 Pin (dBm) Pout (dBm) Vcc=Vbias=3V L2 =10nH (900MHz operation) +85°C -40°C +25°C
REVERSE ISOLATION vs FREQUENCY SUPPLY CURRENT vs BIAS VOLTAGE 00 , 511 , 522 , 53 Vbias (V) Icc total (mA) I bias (mA) Vcc=3V, Ta=+25°C Pin = -40dBm Icc total I bias
ASK TRANSMITTER USING THE TSH690 Application purpose The purpose is to use the TSH690 as a ASK trans- mitter for remote control applications taking bene- fits of the 2 stages architecture, the bias control pin and output power capability. The first transistor stage is devoted to the oscilla- tor by the meaning of a Surface Acoustic Wave (SAW) resonator while the second stage realizes the power amplification to drive antennas includ- ing the impedance matching. Modulation is insured by applying the modulating signal onto the bias pin of TSH690 to get an ampli- tude modulation. Figure 7 : Saw transmitter schematic Oscillator Considerations The oscillator frequency is given by the SAW res- onator which is connected between pins 5 & 7 of the TSH690 to ensure a well-known Colpitts archi- tecture with 2 capacitors C1 and C2. Capacitor C2 is a small value one and, depending on PCB, could be directly obtained from parasitics of mi- crostrip lines. Center frequency is tuned with the trimmer capacitor C1. Note that the pin 7 is internally connected to an in- tegrated self inductor L1 which is wired to the col- lector of the first stage transistor. A resistor R1 is placed to avoid resonance between L1 and C1 but also to adjust the current consumption of the oscil- lator. Moreover, start-up conditions and output harmon- ics levels are related to the R1 value, so that its recommended to use a potentiometer for R1. By tuning R1 and C1, stability of the circuit can be guaranted disregarding the load impedance of the output stage. Output Stage The output matching is defined for a 50Ω load im- pedance by adding a 100nH self-inductor L2 as load to the open collector of the output stage while capacitor C3 is just placed as a DC block with the antenna. In such described conditions, output power on fun- damental reaches more than +13dBm under 3V with an average current consumption of 50mA featuring 2nd & 3rd harmonics levels respectively of -18dBc et -27dBc. Modulation As a result of applying a modulating signal to the bias pin (pin 8), the TSH690 features an amplitude modulation up to the On-Off-Keying when the modulating signal is digital. A series resistor R2 can be added on pin 8 to change biasing conditions but also oscillating con- ditions and finally the available output power. In most of applications, this resistor can be omitted. In the case of digital modulation control, when a ‘0’ logic level is applied on pin 8, the circuit in set in Standby mode during which the oscillator is stopped whereas during a ‘1’ logic level, the circuit radiates RF wave due to oscillator running mode.The maximum data rate of modulating sig- nal is given by the oscillator turn-on time which is typically of 200µs to reach the nominal operating frequency and amplitude. Note that the turn-off time is negligeable. Thus, it is recommended to use a data rate of 2400b/s to keep a duty cycle of 25% (T_ON~200 µs, T_OFF~(400+200)µs). For a higher data rate (maximum of 4800b/s), duty cycle on transmission side decreases drastically so that it is recommended to use a monostable on recep- tion side to recover a correct 50% duty cycle. In or- der to decrease the spectrum shape of transmis- sion, a simple low-pass filter can be added in front of pin 8 to attenuate high level harmonics of the modulating signal.
8 PINS - PLASTIC MICROPACKAGE (SO)
Dim. Millimeters Inches A 1.75 0.069 a1 0.1 0.25 0.004 0.010 a2 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 c1 45° (typ.) D 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F 3.8 4.0 0.150 0.157 L 0.4 1.27 0.016 0.050 M 0.6 0.024 S 8° (max.) Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. © The ST logo is a registered trademark of STMicroelectronics © 2001 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom © http://www.st.com