REV. C
M112685
DAT-31575-SP
070930
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Product Features
• Single positive supply voltage, +3V
• Immune to latch up
• Excellent accuracy, 0.1 dB Typ
• Serial control interface
• Low Insertion Loss
• High IP3, +52 dBm
• Very low DC power consumption
• Excellent return loss, 20 dB Typ
• Small size 4.0 x 4.0 mm
Typical Applications
• Base Station Infrastructure
• Portable Wireless
• CATV & DBS
• MMDS & Wireless LAN
• Wireless Local Loop
• UNII & Hiper LAN
• Power amplifier distortion canceling loops
General Description
The DAT-31575-SP is a 757 RF digital step attenuator that offers an attenuation range up to 31.5 dB in
0.5 dB steps. The control is a 6-bit serial interface, operating on a single +3 volt supply. The DAT-31575-SP
is produced using a unique CMOS process on silicon, offering the performance of GaAs, with the advan-
tages of conventional CMOS devices.
Digital Step Attenuator
31.5 dB, 0.5 dB Step
6 Bit, Serial Control Interface, Single Positive Supply Voltage, +3V
757 DC-2000 MHz
Simplified Schematic
Digital Serial Control
RF Input
16dB 8dB 4dB 2dB 1dB 0.5dB
RF Out
DAT-31575-SP+
DAT-31575-SP
+ RoHS compliant in accordance
with EU Directive (2002/95/EC)
The +Suffix identifies RoHS Compliance. See our web site
for RoHS Compliance methodologies and qualifications.
DAT-31575-SP
Digital Step Attenuator
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DAT-31575-SP+
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RF Electrical Specifications, DC-2000 MHz, TAMB=25°C, VDD=+3V
Absolute Maximum Ratings
Parameter Ratings
Operating Temperature -40°C to 85°C
Storage Temperature -55°C to 100°C
VDD -0.3V Min., 4V Max.
Voltage on any input -0.3V Min., VDD+0.3V Max.
ESD, HBM 500V
ESD, MM 100V
Input Power +24dBm
Parameter Min. Typ. Max. Units
V
DD
, Supply Voltage 2.7 3 3.3 V
I
DD
, Supply Current — — 100 μA
Control Input Low — — 0.3xV
DD
V
Control Input High 0.7xV
DD
——V
Control Current — — 1 μA
DC Electrical Specifications
Parameter Min. Typ. Max. Units
Switching Speed, 50% Control to 0.5dB
of Attenuation Value — 1.0 —
μ
Sec
Switching Control Frequency — — 25 KHz
Switching Specifications
2. Input IP3 and 1dB compression degrades below 1 MHz
Parameter Freq. Range
(GHz) Min. Typ. Max. Units
Accuracy @ 0.5 dB Attenuation Setting DC-1.2 — 0.03 0.17 dB
1.2-2.0 — 0.05 0.18 dB
Accuracy @ 1 dB Attenuation Setting
DC-1.2 — 0.03 0.24 dB
1.2-2.0 — 0.1 0.25 dB
Accuracy @ 2 dB Attenuation Setting DC-1.2 — 0.07 0.28 dB
1.2-2.0 — 0.15 0.3 dB
Accuracy @ 4 dB Attenuation Setting DC-1.2 — 0.05 0.36 dB
1.2-2.0 — 0.15 0.4 dB
Accuracy @ 8 dB Attenuation Setting DC-1.2 — 0.1 0.52 dB
1.2-2.0 — 0.24 0.6 dB
Accuracy @ 16 dB Attenuation Setting DC-1.2 — 0.23 0.84 dB
1.2-2.0 — 0.8 1.0 dB
Insertion Loss(note1) @ all attenuator set to 0dB DC-1.2 — 1.2 1.8 dB
1.2-2.0 — 1.6 2.1 dB
Input IP3(note2) (at Min. and Max. Attenuation) DC-2.0 — +52 — dBm
Input Power @ 0.2dB Compression (note2)
(at Min. and Max. Attenuation) DC-2.0 — +24 — dBm
VSWR DC-1.2 — 1.6 2.0 —
1.2-2.0 — 1.7 2.0 —
Notes:
1. I. Loss values are de-embedded from test board Loss (test board’s Insertion Loss: 0.10dB @100MHz, 0.40dB @1200MHz,
0.55dB @2000MHz, 0.75dB @4000MHz)
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DAT-31575-SP
Digital Step Attenuator DAT-31575-SP+
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Function Pin
Number Description
C16 1 Control for Attenuation bit, 16 dB (Notes 3,4)
RF in 2 RF in port (Note 1)
Data 3 Serial Interface data input (Note 3)
Clock 4 Serial Interface clock input
LE 5 Latch Enable Input (Note 2)
VDD 6 Power Supply
N/C 7 Not connected
N/C 8 Not connected
VDD 9 Power Supply
GND 10 Ground connection
GND 11 Ground connection
GND 12 Ground connection
VDD 13 Power Supply
RF out 14 RF out port (Note 1)
C8 15 Control for attenuation bit, 8 dB (Note 4)
C4 16 Control for attenuation bit, 4 dB (Note 4)
C2 17 Control for attenuation bit, 2 dB (Note 4)
GND 18 Ground Connection
C1 19 Control for attenuation bit, 1 dB (Note 4)
C0.5 20 Control for attenuation bit, 0.5 dB (Note 4)
GND Paddle Paddle ground (Note 5)
Notes:
1. Both RF ports must be held at 0VDC or DC blocked with an external series capacitor.
2. Latch Enable (LE) has an internal 100KΩ resistor to VDD.
3. Place a 10KΩ resistor in series, as close to pin as possible to avoid freq. resonance.
4. Refer to Power-up Control Settings.
5. The exposed solder pad on the bottom of the package (See Pin configuration) must
be grounded for proper device operation.
Pin Description
GND
GND
GND
GND
VDD
VDD
VDD
N/C
N/C
RFout
C8
LE
Clock
Data
RFin
C16
C4
C2
C1
C0.5
2x2mm
Paddle
ground
15
14
13
12
11
1
2
3
4
5
6
7
8
9
20
19
18
17
1610
Pin Configuration (Top View)
DAT-31575-SP
Digital Step Attenuator
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DAT-31575-SP+
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Typical Performance Curves
ATTENUATION (0.5dB) @ +25°C, +85°C, -45°C
0
0.2
0.4
0.6
0.8
1
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
ATTENUATION (1dB) @ +25°C, +85°C, -45°C
0.4
0.6
0.8
1
1.2
1.4
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
ATTENUATION (2dB) @ +25°C, +85°C, -45°C
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
ATTENUATION (4dB) @ +25°C, +85°C, -45°C
3
3.2
3.4
3.6
3.8
4
4.2
4.4
4.6
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
ATTENUATION (8dB) @ +25°C, +85°C, -45°C
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
8
8.2
8.4
8.6
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
INSERTION LOSS (Ref) @ +25°C, +85°C, -45°C
0
1
2
3
4
5
6
7
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
+85°C
+25°C
-45°C
DAT-31575-SP
Digital Step Attenuator
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DAT-31575-SP+
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Typical Performance Curves
ATTENUATION (16dB) @ +25°C, +85°C, -45°C
12
12.5
13
13.5
14
14.5
15
15.5
16
16.5
17
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
RETURN LOSS IN S11 (Ref) @ +25°C, +85°C, -45°C
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
RETURN LOSS OUT S22 (Ref) @ +25°C, +85°C, -45°C
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
RETURN LOSS IN S11 (Major Attenuation Steps) @ +25°C
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
ATT=0dB ATT=0.5dB
ATT=1dB ATT=2dB
ATT=4dB ATT=8dB
ATT=16dB ATT=31.5dB
RETURN LOSS OUT S22 (Major Attenuation Steps) @ +25°C
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
ATT=0dB ATT=0.5dB
ATT=1dB ATT=2dB
ATT=4dB
ATT=8dB
ATT=16dB ATT=31.5dB
ATTENUATION (31.5dB) @ +25°C, +85°C, -45°C
22
23
24
25
26
27
28
29
30
31
32
33
0 500 1000 1500 2000 2500 3000
Frequency (MHz)
(dB)
-45°C
+25°C
+85°C
DAT-31575-SP
Digital Step Attenuator
Page 6 of 12
DAT-31575-SP+
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Typical Performance Curves
IP-3 INPUT (Major Attenuation Steps) @ +25°C
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 200
0
Frequency (MHz)
(dBm)
ATT=0dB
ATT=0.5dB
ATT=1dB
ATT=2dB
ATT=4dB
ATT=8dB
ATT=16dB
ATT=31.5dB
IP-3 INPUT (Major Attenuation Steps) @ +85°C
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
(dBm)
ATT=0dB
ATT=0.5dB
ATT=1dB
ATT=2dB
ATT=4dB
ATT=8dB
ATT=16dB
ATT=31.5dB
IP-3 INPUT (Major Attenuation Steps) @ -45°C
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
(dBm)
ATT=0dB
ATT=0.5dB
ATT=1dB
ATT=2dB
ATT=4dB
ATT=8dB
ATT=16dB
ATT=31.5dB
COMPRESSION @INPUT POWER=+24dBm (+25°C)
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
(dB)
ATT=0dB ATT=0.5dB
ATT=1dB ATT=2dB
ATT=4dB
ATT=8dB
ATT=16dB ATT=31.5dB
COMPRESSION @INPUT POWER=+24dBm (+85°C)
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
(dB)
ATT=0dB ATT=0.5dB
ATT=1dB
ATT=2dB
ATT=4dB ATT=8dB
ATT=16dB ATT=31.5dB
COMPRESSION @INPUT POWER=+24dBm(-45°C)
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
(dB)
ATT=0dB ATT=0.5dB
ATT=1dB
ATT=2dB
ATT=4dB ATT=8dB
ATT=16dB ATT=31.5dB
Page 7 of 12
DAT-31575-SP
Digital Step Attenuator DAT-31575-SP+
'.)''#$/&-')#.')+"$()')%&*(**!'(("& '&$"&*"&""),"+*-*"+
Outline Drawing (DG983-1)
Device Marking
31575
Suggested Layout,
Tolerance to be within ±.002
PCB Land Pattern
Outline Dimensions ( )
inch
mm
A
BCDEFGHJ K L M N P Q R WT.
GRAMS
.157 .157 .035 .008 .081 .081 .010 — .022 .020 .166 .166 .070 .012 .020 .070 .04
4.00 4.00 0.90 0.20 2.06 2.06 0.25 — 0.56 0.50 4.22 4.22 1.78 0.31 0.51 1.78
DAT-31575-SP
Digital Step Attenuator
Page 8 of 12
DAT-31575-SP+
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Suggested Layout for PCB Design (PL-186)
The suggested Layout shows only the footprint area of the DAT, and the components located near this area
(i.e.: R1-R7). For the complete Layout, see photo and schematic diagram on page 11 of 12.
NOTES:
1. TRACE WIDTH IS SHOWN FOR FR4 WITH DIELECTRIC THICKNESS.
.025” ±.002”. COPPER: 1/2 OZ. EACH SIDE.
FOR OTHER MATERIALS TRACE WIDTH MAY NEED TO BE MODIFIED.
2. 0603 SIZE CHIP FOOT PRINTS SHOWN FOR REFERENCE,
VALUES OF RESISTORS WILL VARY BASED ON APPLICATION.
3. BOTTOM SIDE OF THE PCB IS CONTINUOUS GROUND PLANE.
DENOTES PCB COPPER LAYOUT WITH SMOBC
(SOLDER MASK OVER BARE COPPER)
DENOTES COPPER LAND PATTERN FREE OF SOLDERMASK
Page 9 of 12
DAT-31575-SP
Digital Step Attenuator DAT-31575-SP+
'.)''#$/&-')#.')+"$()')%&*(**!'(("& '&$"&*"&""),"+*-*"+
The serial interface is a 6-bit serial in, parallel-out shift register buffered by a transparent latch.
It is controlled by three CMOS-compatible signals: Data, Clock, and Latch Enable (LE). The Data and Clock
inputs allow data to be serially entered into the shift register, a process that is independent of the state of
the LE input.
The LE input controls the latch. When LE is HIGH, the latch is transparent and the contents of the serial shift
register control the attenuator. When LE is brought LOW, data in the shift register is latched.
The shift register should be loaded while LE is held LOW to prevent the attenuator value from changing as
data is entered. The LE input should then be toggled HIGH and brought LOW again, latching the new data.
The timing for this operation is defined by Figure 1 (Serial Interface Timing Diagram) and Table 2 (Serial
Interface AC Characteristics).
Simplified Schematic
Figure 1: Serial Interface Timing Diagram
Table 2. Serial Interface AC Characteristics
Symbol Parameter Min. Max. Units
fclk
Serial data clock
frequency (Note 1) 10 MHz
tclkH Serial clock HIGH time 30 ns
tclkL Serial clock LOW time 30 ns
tLESUP
LE set-up time after last
clock falling edge 10 ns
tLEPW
LE minimum pulse
width 30 ns
tSDSUP
Serial data set-up time
before clock rising edge 10 ns
tSDHLD
Serial data hold time
after clock falling edge 10 ns
Note 1. fclk verified during the functional pattern test. Serial programming
sections of the functional pattern are clocked at 10MHz to verify fclk speci-
fication.
The DAT-31575-SP Serial interface consists of 6 control bits that select the desired attenuation state, as
shown in Table 1: Truth Table
Table 1. Truth Table
Attenuation
State C16 C8 C4 C2 C1 C0.5
Reference 0 00000
0.5 (dB) 0 00001
1 (dB) 0 00010
2 (dB) 0 00100
4 (dB) 0 01000
8 (dB) 0 10000
16 (dB) 1 00000
31.5 (dB) 1 11111
Note: Not all 64 possible combinations of C0.5 - C16 are shown in table
LE
Clock
Data MSB LSB
t
LESUP
t
SDSUP
t
SDHLD
t
LEPW
Digital Serial Control
RF Input
16dB 8dB 4dB 2dB
1dB 0.5dB
RF Out
DAT-31575-SP
Digital Step Attenuator
Page 10 of 12
DAT-31575-SP+
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The DAT-31575-SP, uses a common 6-bit serial word format, as shown in Table 3: 6-Bit attenuator Serial
Programming Register Map.
The first bit, the MSB, corresponds to the 16-dB Step and the last bit, the LSB, corresponds to the 0.5 dB step.
The DAT-31575-SP always assumes a specifiable attenuation setting on power-up, allowing a known at-
tenuation state to be established before an initial serial control word is provided.
When the attenuator powers up, the six control bits are set to whatever data is present on the six data inputs
(C0.5 to C16).
This allows any one of the 64 attenuation settings to be specified as the power-up state.
Power-up Control Settings
Table 3. 6-Bit attenuator Serial Programming Register Map
B5 B4 B3 B2 B1 B0
C16 C8 C4 C2 C1 C0.5
MSB
(first in)
LSB
(last in)
Page 11 of 12
DAT-31575-SP
Digital Step Attenuator DAT-31575-SP+
'.)''#$/&-')#.')+"$()')%&*(**!'(("& '&$"&*"&""),"+*-*"+
TB-344 Evaluation Board Schematic Diagram
DAT
C0.5
C1
GND
C2
C4
C16
DATA
Clock
LE
VDD
VDD
GND
C8
VDD
GND
R1
R2
R3 R4
R5
R6
R7
IC1
RFin RFout
Connected to +VDD
64 2
R8
R9
R11
C6
R10
+Vcc
C1
C2
C3
C4
C5
N/C
N/C
20 19 18 17 16
15
14
13
12
11
109876
5
4
3
2
1
147
135
8101213119
CLOCK
LE
DATA
GND
DATA
LE
CLK
GND
N/C
12345
SERIAL
CONTROL
J1
CLOCK
LE
DATA
GND
GND
GND
VDD
1234
DC SUPPLY
J2
GND
RFin RFout
+
TB-344
Bill of Materials
R1 - R11 Resistor 0603 10 KOhm +/- 1%
C1 - C5 NPO Capacitor 0603 100pF +/- 5%
C6, C7 Tantalum Capacitor 100nF +/- 10%
IC1 Hex inverting Schmitt trigger MM74HC14
DAT-31575-SP
Digital Step Attenuator
Page 12 of 12
DAT-31575-SP+
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Tape and Reel Packaging Information
Table T&R
TR
No.
No. of Devices Designation
Letter
Reel Size Tape
Width
Pitch Unit
Orientation
3000 T 13 inch
T-005
multiples of 10,
less than full
reel of 1K
PR 13 inch
12 mm 8 mm
multiples of 10,
on tape only Enot
applicable
Ordering Information
Model No. Description
Packaging
Designation Letter
(See Table T&R)
Quantity
Min.
No. of Units
Price
$
Ea.
DAT-31575-SP (+) Serial Interface,
Single Positive Voltage E 10 $3.80
TB-344 Test Board Only Not Applicable 1 $79.95
How to Order
Example: 3000 pieces of DAT-31575-SP+
1K DAT-31575-SP+ T&R=T
Quantity Model No. T&R designation letter (see Table T&R)
Direction of Feed
Tape
Cavity
