AWM6423 Reduced Leakage Current in Off State

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: Mktg@anadigics.com
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