QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1150A BROADBAND ULTRA LOW DISTORTION 7-BIT DIGITALLY CONTROLLED VGA LT5554 DESCRIPTION Demonstration circuit 1150A 1150A is a featuring the With 0.125dB step resolution and 5ns settling time, the LTC5554 IC, a 7-bit programmable gain amplifier. It in- LT5554 may be suited in quasi-continuous gain control corporates a variety of passive components to support applications. configurations for varied applications. The LT5554 power and voltage gain for Maximum Gain The LT5554 is a differential input and output precision is 18dB when application R =50. Application gain can out programmable gain amplifier with 16dB gain range and be changed with different R selections. out 0.125dB gain step. The LT5554 amplifier is unconditionally stable. Conse- The seven LT5554 gain control inputs (PGx, x=0,2,..6) quently, LC-filters or SAW filters can be connected to the and the STROBE input can be coupled to TTL (DC- LT5554 I/O pins without padding. coupling type) or ECL and (low-voltage) CMOS drivers Lacking global feed-back, the LT5554 has -80dB reverse (AC-coupling type) without external components. The 3- isolation 400MHz (package limited). state MODE pin allows the selection of the coupling type. The LT5554 gain state can be updated asynchronously when STROBE is HIGH or synchronously using the Design files for this circuit board are available. Call STROBE input positive transition. In the latter STROBED- the LTC factory. MODE, the external control logic time skew is eliminated PowerPath is a trademark of Linear Technology Corporation and synchronization with the ADC clock is possible. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1150A BROADBAND ULTRA LOW DISTORTION 7-BIT DIGITALLY CONTROLLED VGA Table 1. Typical DEMO BOARD Performance Summary T = 25C, V = 5V, VccO = 5V, ENB = 3V, MODE = 5v, STROBE = 2.2V, H = A CC IH 2.2V, MAXIMUM GAIN, P = 4dBm/Tone (2V into 50WWWW), DDDDf = 200KHz OUT P-P SYMBOL PARAMETER CONDITIONS TYPICAL PERFORMANCE UNIT V Supply Voltage 4.75 to 5.25 V CC (For more detail, Please see Note 4 of V O OUT Output Pin DC Common Mode Voltage 3.5 to 6 V CC data sheet) I V Supply Current V 100 mA CC CC CC = 5V I OUT Quiescent Current OUT Voltages = 5V 96 mA ODC R Input Resistance F =100MHz 45 W IN IN C Input Capacitance F =100MHz 2.8 F IN IN P R Output Resistance F =100MHz 400 W O IN C Output Capacitance F =100MHz 1.9 F O IN P Pout=10dBm (Single Tone), HD2 Second Harmonic Distortion -76 dBc F =100MHz, R = 50W IN OUT Pout=10dBm (Single Tone), HD3 Third Harmonic Distortion -62 dBc F =100MHz, R = 50W IN OUT R OUT 100WWWW 50WW WW G Maximum Voltage Gain F =200MHz 13.7 19.6 dB VMAX IN G Maximum Power Gain F =200MHz 13.6 16.6 dB PMAX IN IIP3 Input Third Order Intercept Point F =200MHz 27.8 27 dBm IN OIP3 Output Third Order Intercept Point F =200MHz 41.5 44 dBm IN IMD3 Intermodulation Product F =200MHz -84 -88 dBc IN V Output Noise Noise Spectral Density F =200MHz 10.7 21.4 nV/Hz ONOISE IN NF Noise Figure F =200MHz 10 10 dB IN RTI Input Referred Noise Spectral Density F =200MHz 1.34 1.34 nV/Hz IN SFDR Spurious Free Dynamic Range F =200MHz 128 128 dBm/Hz IN Table 2. DC1150A Board I/O Description CONNECTOR FUNCTION COMMENTS J1 Singe-Ended Input 50W Signal source, no external termination necessary J3 Singe-Ended Output 50W matched, can drive network/spectrum analyzer input VCC LT5554 VCC pin. Connect to power supply 5V. VCCO Output bias voltage Connect to power supply 5V. VPG Bias STROBE and all PGx via Connect to power supply in 3 to 5V range for Maximum Gain state. Connect to GROUND for Mini- 10KW resistors. mum Gain state. ENABLE Enable/Shut-down Connect to 5V to enable LT5554, or connect to GND for shut-down. 2