Application Note AWM6423 Reduced Leakage Current in Off State Revision 0 RELEVANT PRODUCTS • AWM6423 OVERVIEW The ANADIGICS AWM6423 WiMAX Power Amplifier is a high performance device that delivers exceptional linearity and efficiency at high levels of output power. The device can be shut down without disconnecting it from the main power supply (nominally +2.9 V to +4.2 V) by dropping its bias voltage (Pin 4) below +0.7 V. Using the application circuit detailed in the AWM6423 product data sheet, in this “shut down” or “off” state, the device will draw about 1 to 1.5 mA of current from Pin 5, and negligible current from Pins 1 and 12. For applications in which the power supply is a battery source and minimal power consumption in the off state is critical, the AWM6423 application circuit can be re-configured such that the off state current draw becomes less than 100 µA altogether. LOW OFF STATE LEAKAGE CURRENT APPLICATION CIRCUIT By connecting Pin 5 of the AWM6423 to the bias voltage input (Pin 4), instead of to the main power supply, the circuitry that draws current from Pin 5 is effectively shut down, and the total leakage current from the AWM6423 is reduced to less than 100 µA (see Figure 1). In this configuration, the typical current consumption from the +2.85 V bias voltage (for Pins 4 and 5 combined) is approximately 8 mA, using a +3.3 V main supply. VCC VCC 2.2 µF 0.01 µF 1 2 RFIN 3 4 VBIAS 5 100 pF VATTN 6 VCC3 VCCC RF IN GND GND RFOUT V BIAS GND VCC_ATTN GND VATTN DET GND at Slug 1 µF 11 10 RFOUT 9 8 7 DETOUT 4.7 K 0.1 µF Figure 1: AWM6423 Low Leakage Current Application Circuit 04/2007 2.2 µF 12 AWM6423 Reduced Leakage Current in Off State Figures 2 through 5 illustrate AWM6423 performance when Pin 5 in connected to Pin 4 directly, as in the Figure 1 application circuit: Figure 2: Gain vs. Output Power (TC = 25oC, VCC = +3.3 V, VBIAS = +2.85 V, 54 Mbps OFDM Modulation, Pin 5 Connected to Pin 4) Figure 3: Uncorrected EVM vs. Output Power (TC = 25oC, VCC = +3.3 V, VBIAS = +2.85 V, 54 Mbps OFDM Modulation, system EVM approx. 0.8 %, Pin 5 Connected to Pin 4) 6.0 33 5.5 32 5.0 Uncorrected EVM (%) 31 Gain (dB) 30 29 28 Frequency 27 2.5 GHz 2.6 GHz 2.7 GHz 26 Frequency 4.5 2.5 GHz 2.6 GHz 2.7 GHz 4.0 3.5 3.0 2.5 2.0 1.5 25 1.0 24 0.5 0.0 23 11 12 13 14 15 16 17 18 19 20 21 22 23 24 11 25 12 13 14 15 Figure 4: Supply Current vs. Output Power (TC = 25oC, VCC = +3.3 V, VBIAS = +2.85 V, 54 Mbps OFDM Modulation, Pin 5 Connected to Pin 4) 17 18 19 20 21 22 23 24 25 Figure 5: Detector Voltage vs. Output Power (TC = 25oC, VCC = +3.3 V, VBIAS = +2.85 V, 54 Mbps OFDM Modulation, Pin 5 Connected to Pin 4) 0.375 2.00 0.350 1.75 0.325 Frequency Frequency 0.275 Detector Voltage (V) 2.5 GHz 2.6 GHz 2.7 GHz 0.300 Icc (A) 16 Output Power (dBm) Output Power (dBm) 0.250 0.225 0.200 0.175 1.50 2.5 GHz 2.6 GHz 2.7 GHz 1.25 1.00 0.75 0.50 0.150 0.25 0.125 0.100 0.00 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 11 12 Output Power (dBm) 14 15 16 17 18 19 20 21 22 23 24 25 Output Power (dBm) ADDITIONAL CONSIDERATION Reducing the on state voltage to Pin 5 of the AWM6423 to +2.85 V (because it is now connected to the bias voltage rather than to the main supply) limits the output voltage range of the integrated output power detector, and at higher output power 2 13 levels affects the relationship between the detector output voltage and the PA output power. For details regarding typical detector voltage variation versus main supply voltage, please refer to the AWM6423 data sheet. Application Note - Rev 0 04/2007 AWM6423 Reduced Leakage Current in Off State NOTES Application Note - Rev 0 04/2007 3 AWM6423 Reduced Leakage Current in Off State ANADIGICS, Inc. 141 Mount Bethel Road Warren, New Jersey 07059, U.S.A. Tel: +1 (908) 668-5000 Fax: +1 (908) 668-5132 URL: http://www.anadigics.com E-mail: [email protected] IMPORTANT NOTICE ANADIGICS, Inc. reserves the right to make changes to its products or to discontinue any product at any time without notice. The product specifications contained in Advanced Product Information sheets and Preliminary Data Sheets are subject to change prior to a product’s formal introduction. Information in Data Sheets have been carefully checked and are assumed to be reliable; however, ANADIGICS assumes no responsibilities for inaccuracies. ANADIGICS strongly urges customers to verify that the information they are using is current before placing orders. WARNING ANADIGICS products are not intended for use in life support appliances, devices or systems. Use of an ANADIGICS product in any such application without written consent is prohibited. 4 Application Note - Rev 0 04/2007