RFSA2644
Serial Con-
trolled Digital
Step Attenua-
tor
RFSA2644
SERIAL CONTROLLED DIGITAL STEP ATTENUATOR
50MHz TO 4000MHz, 6-BIT, 0.5dB LSB
Package: MCM, 24-Pin, 4.2mm x 4.2mm
DATA
PUP
20
NC
CLK
24
23
22
21
Features
NC
19
LE
GND
VDD
GND
RF1
GND
GND
1
18
GND
GND
GND
RF2
GND
GND
Frequency Range 50MHz to
4000MHz
6-Bits, 31.5dB Range, 0.5dB
Step
High Linearity, IP3 >48dBm
3V and 5V Logic Compatible
Serial-to-Parallel Controller
Serial Programming Interface
Power-up Programming Modes
On-Chip ESD Protection Class 1C
HBM
Single Supply, 3V to 5V Operation
Footprint Compatible with Most
24-Pin, 4mm x 4mm, QFNs
2
SPI
17
3
16
4
15
5
6-Bit DSA
14
6
13
7
8
9
10
11
12
GND
GND
GND
GND
Functional Block Diagram
Product Description
RFMD’s RFSA2644 is a 6-bit digital step attenuator (DSA) that features high linear-
ity over the entire 31.5dB gain control range with excellent step accuracy in 0.5dB
steps. The RFSA2644 is programmed via a serial mode control interface that is
both 3V and 5V compatible. The RFSA2644 also offers a rugged Class 1C HBM ESD
rating via on-chip ESD circuitry. The MCM package is footprint compatible with most
24-pin, 4mm x 4mm, QFN packages.
Applications
Transceiver RF and IF
Applications
Cellular, PCS, GSM, UMTS, LTE,
WiMax/WiFi
Wireless Data, Satellite
Terminals
Test Equipment
Ordering Information
RFSA2644SR
RFSA2644SQ
RFSA2644TR7
RFSA2644TR13
RFSA2644PCK-410
7” Sample reel with 100 pieces
25-Piece sample bag
7” Reel with 750 pieces
13” Reel with 2500 pieces
50MHz to 4000MHz PCBA with 5-piece sample bag
Optimum Technology Matching® Applied
GaAs HBT
GaAs MESFET
InGaP HBT
SiGe BiCMOS
Si BiCMOS
SiGe HBT
GND
GaAs pHEMT
Si CMOS
Si BJT
GND
GaN HEMT
BiFET HBT
RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trade-
mark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2012, RF Micro Devices, Inc.
DS120706
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.
1 of 12
RFSA2644
Absolute Maximum Ratings
Parameter
Supply Voltage
DC Supply Current
Power Dissipation
Max RF Input Power
Operating Temperature (T
CASE
)
Storage Temperature
Junction Temperature
ESD Rating (HBM)
Moisture Sensitivity Level
Rating
+5.5
15
83
28.3
-40 to +85
-40 to +150
150
Class 1C
MSL3
Unit
V
mA
mW
dBm
°C
°C
°C
V
Caution! ESD sensitive device.
Exceeding any one or a combination of the Absolute Maximum Rating conditions may
cause permanent damage to the device. Extended application of Absolute Maximum
Rating conditions to the device may reduce device reliability. Specified typical perfor-
mance or functional operation of the device under Absolute Maximum Rating condi-
tions is not implied.
The information in this publication is believed to be accurate and reliable. However, no
responsibility is assumed by RF Micro Devices, Inc. ("RFMD") for its use, nor for any
infringement of patents, or other rights of third parties, resulting from its use. No
license is granted by implication or otherwise under any patent or patent rights of
RFMD. RFMD reserves the right to change component circuitry, recommended appli-
cation circuitry and specifications at any time without prior notice.
RFMD Green: RoHS compliant per EU Directive 2002/95/EC, halogen free
per IEC 61249-2-21, < 1000ppm each of antimony trioxide in polymeric
materials and red phosphorus as a flame retardant, and <2% antimony in
solder.
Parameter
Frequency Range
Insertion Loss
Min.
50
Specification
Typ.
0.6
0.7
0.8
1.2
1.4
1.8
Max.
4000
Unit
MHz
dB
dB
dB
dB
dB
dB
dB
dBm
dBm
dBm
dBm
dBm
dBm
dBm
nS
nS
Condition
5V, 25°C unless otherwise stated
50MHz, 0dB attenuation
500MHz, 0dB attenuation
880MHz, 0dB attenuation
2140MHz, 0dB attenuation
2700MHz, 0dB attenuation
4000MHz, 0dB attenuation
0.5dB step size
Gain Control Range
Step Accuracy
Input IP3
Input P0.5dB
Input Return Loss
Output Return Loss
Control Interface
Settling Time
Switching Speed
Supply Voltage (V
DD
)
Supply Current
Control Voltage (V
CTL
)
4.75
48
20
28
13
10
13
11.5
31.5
±(0.1+5% attenuation range)
55
20.2
30
29
18
27
22
6-Bit, Serial
200
200
5.0
5.2
Low, V
CTL
= 0 to 0.8V
High, V
CTL
= 2.0 to V
DD
5.25
Under 100MHz, all states
150MHz to 1000MHz, all states
Under 2700MHz
2700MHz to 4000MHz
Under 2700MHz
2700MHz to 4000MHz
Serial interface
t
RISE
, t
FALL
(10%/90% RF)
t
ON
, t
OFF
(50% CTL to 10%/90% RF)
V
mA
V
V
Notes:
1. V
DD
= 5V, V
CTL
= 5V, T = 25°C
2. IIP3 measured with P
IN
= 17dBm/tone, 1MHz spacing
2 of 12
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.
DS120706
RFSA2644
Parameter
Frequency Range
Insertion Loss
Min.
50
Specification
Typ.
0.7
0.7
1.0
1.2
1.5
1.8
Max.
4000
Unit
MHz
dB
dB
dB
dB
dB
dB
dB
dBm
dBm
dBm
dBm
dBm
dBm
dBm
nS
nS
Condition
3V, 25°C unless otherwise stated
50MHz, 0dB attenuation
500MHz, 0dB attenuation
880MHz, 0dB attenuation
2140MHz, 0dB attenuation
2700MHz, 0dB attenuation
4000MHz, 0dB attenuation
0.5dB step size
Gain Control Range
Step Accuracy
Input IP3
Input P0.5dB
Input Return Loss
Output Return Loss
Control Interface
Settling Time
Switching Speed
Supply Voltage (V
DD
)
Supply Current
Control Voltage (V
CTL
)
2.8
31.5
±(0.1 + 5% attenuation range)
48
20
27
13
10
13
11
6-Bit, Serial
200
200
3.0
5.0
Low, V
CTL
= 0 to 0.8V
High, V
CTL
= 2.0 to V
DD
3.3
Under 100MHz, all states
1000MHz, all states
Under 2700MHz
2700MHz to 4000MHz
Under 2700MHz
2700MHz to 4000MHz
Serial interface
t
RISE
, t
FALL
(10%/90% RF)
t
ON
, t
OFF
(50% CTL to 10%/90% RF)
V
mA
V
V
Notes:
1. V
DD
= 3V, V
CTL
= 3V, T = 25°C
2. IIP3 measured with P
IN
= 17dBm/tone, 1MHz spacing
DS120706
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.
3 of 12
RFSA2644
Typical Performance at 5V V
DD
- Broadband Application Circuit
Insertion Loss versus Frequency
2.5
0
Normalized Attenuation versus Frequency
-5
2.0
-10
Insertion Loss (dB)
1.5
Attenuation (dB)
-15
1.0
-40°C
0.5
25°C
85°C
0.0
0
1,000
2,000
3,000
4,000
-20
0.5
-25
4
31.5
-30
1
8
2
16
-35
0
1000
2000
3000
4000
Frequency (MHz)
Frequency (MHz)
Input Return Loss versus Frequency
45
40
35
50
45
40
Output Return Loss versus Frequency
Output Return Loss (dB)
Input Return Loss (dB)
30
25
20
15
10
5
0
0
1000
2000
3000
4000
0dB
2dB
16dB
0.5dB
4dB
31.5dB
1dB
8dB
35
30
25
20
15
10
5
0
0
1000
2000
3000
4000
0dB
2dB
16dB
0.5dB
4dB
31.5dB
1dB
8dB
Frequency (MHz)
Frequency (MHz)
Relative Phase versus Frequency
60
1.00
50
0.5dB
2dB
8dB
1dB
4dB
16dB
0.75
Worst Case Step Error Between
Successive States
Relative Phase (Deg)
40
Worst Case Step Error (dB)
2000
3000
31.5dB
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
30
20
10
0
-10
0
1000
4000
0
1000
2000
3000
4000
Frequency (MHz)
Frequency (MHz)
4 of 12
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.
DS120706
RFSA2644
Typical Performance at 5V V
DD
- Broadband Application Circuit
Major Step Error Versus Frequency
1.00
0.5dB
4dB
0.50
31.5dB
0.4
1dB
8dB
2dB
16dB
1.0
0.8
0.6
50MHz
1000MHz
3000MHz
400MHz
2000MHz
4000MHz
Step Error versus Attenuation
0.75
Step Error (dB)
Step Error (dB)
0
1000
2000
3000
4000
0.25
0.2
0.0
-0.2
-0.4
0.00
-0.25
-0.50
-0.6
-0.75
-0.8
-1.0
0
4
8
12
-1.00
Frequency (MHz)
16
20
Attenuation (dB)
24
28
32
Input IP3 versus Frequency
60
35
Input P0.5dB versus Frequency
55
30
45
Input P0.5dB (dB)
Input IP3 (dBm)
50
25
40
0dB
35
2dB
16dB
30
0
500
1000
1500
2000
2500
3000
0.5dB
4dB
31.5dB
1dB
8dB
0dB
20
2dB
16dB
0.5dB
4dB
31.5dB
1dB
8dB
15
0
100
200
300
400
500
600
700
800
900
1000
Frequency (MHz)
Frequency (MHz)
DS120706
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.
5 of 12
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