ams AS1502 Digital potentiometer Datasheet

Data Sheet AS1500/1/2/3
Digital Potentiometer
AS1500/AS1501/AS1502/AS1503
Key Features
-
-
DATASHEET
PRELIMINARY FACT SHEET
programming rates up to 10MHz. The AS1500 is available in
four different resistor values. The AS1500 incorporates a
256-Position
Available in four Resistance values
- AS1500 resistance 10kOhms
- AS1501 resistance 20kOhms
- AS1502 resistance 50kOhms
- AS1503 resistance 100kOhms
Power Shutdown —Less than 1 µA
3-Wire SPI-Compatible Serial Data Input
10 MHz Update Data Loading Rate
2.7 V to 5.5 V Single-Supply Operation
Temperature Range –40°C to +125°C
Package SO-8
Compatible to AD8400
10kΩ, the AS1501 a 20kΩ, the AS1502 a 50kΩ and the
AS1503 a 100kΩ fixed resistor. The wiper contact taps the
fixed resistor at points determined by the 8-bit digital code
word. The resistance between the wiper and the endpoint of
the resistor is linear. The switching action is performed in a
way that no glitches occur. Furthermore the AS150x product
family includes a shutdown mode, where it consumes less
than 1µA. The AS150x is available in an 8-pin SOIC
package. All parts are guaranteed to operate over the
extended industrial temperature range of –40°C to +125°C.
Applications
General Description
-
The AS1500 is a digital potentiometer with 256
programmable steps. The values of the resistor can be
controlled via 3 wire serial interface capable to handle
-
Line Impedance Matching
Volume Control, Panning
Mechanical Potentiometer Replacement
Power Supply Adjustment
Programmable Filters, Delays, Time Constants
VDD
B 1
GND 2
CSN 3
SDI
4
8
AS150x
Top View
A
SDI
7
W
CK
6
VDD
CSN
5
CK
A
10 Bit
Serial
Latch
8
8-Bit
Latch
8
W
B
AS1500
GND
Figure 1
Pinout andfunctional Block Diagram of Digital Potentiometer AS150x family
Revision 1.0, Oct 2004
Page 1 of 8
Data Sheet AS1500/1/2/3
ABSOLUTE MAXIMUM RATINGS
(TA = 25°C, unless otherwise noted.)
Parameter
VDD to GND
VA, VB, VW to GND
AX – BX, AX – WX, BX – WX
Digital Input and Output Voltage to GND
Operating Temperature Range
Maximum Junction Temperature (TJ max)
Storage Temperature
Package body temperature 1
Limits
–0.3V, +7V
0V, VDD
±20mA
0V, +7V
–40°C to +125°C
150°C
–65°C to +150°C
260°C
Package Power Dissipation
(TJ max – TA) / θJA
ESD
1kV
2
Table 1: Absolute Maximum Ratings
Pin
1
2
3
4
5
6
7
8
Table
1
2
Name
B
GND
Description
Terminal B RDAC
Ground
Chip Select Input, Active Low. When CS returns high,
CSN
data in the serial input register is loaded into the DAC
register.
SDI
Serial Data Input
CK
Serial Clock Input, Positive Edge Triggered.
Positive power supply, specified for operation at both 3V
VDD
and 5V.
W
Wiper RDAC
A
Terminal A RDAC
2: Pin Function Description
The reflow peak soldering temperature (body temperature) is specified according IPC/JEDEC J-STD-020C “Moisture/Reflow Sensitivity
Classification for non hermetic Solid State Surface Mount Devices”.
HBM MIL-Std883E 3015.7methods.
Revision 1.0, Oct 2004
Page 2 of 8
Data Sheet AS1500/1/2/3
AS1500 / AS1501 – SPECIFICATIONS
VDD = 3V±10% or 5V±10%, V A = VDD, V B = 0V, –40°C ≤ T A ≤ +125°C unless otherwise noted.
ELECTRICAL CHARACTERISTICS – 10k and 20k VERSIONS
Parameter
Symbol Conditions
DC CHARACTERISTICS RHEOSTAT MODE
T A = 25°C, VDD = 5V, AS1500, Version: 10kΩ
Nominal Resistance 4
R AB
T A = 25°C, VDD = 5V, AS1501, Version: 20kΩ
Resistance Tempco 5
∆R AB /∆T V AB = VDD, Wiper = No Connect
Wiper Resistance
RW
VDD = 5V
Resistor Differential NL 6
R-DNL R WB , VDD = 5V, V A = No Connect
Resistor Integral NL
R-INL
R WB , VDD = 5V, V A = No Connect
DC CHARACTERISTICS POTENTIOMETER DIVIDER
Resolution
N
VDD = 5.5V T A = 25°C
Integral Nonlinearity
INL
VDD = 2.7V T A = 25°C
VDD = 5.5V T A = 25°C
Differential Nonlinearity
DNL
VDD = 2.7V T A = 25°C
Voltage Divider Tempco
∆V W /∆T Code = 80 H
Full-Scale Error
V WFSE
Code = FF H , VDD = 5.5V
Zero-Scale Error
V WZSE
Code = 00 H , VDD = 5.5V
RESISTOR TERMINALS
Voltage Range 7
V A, B, W
Capacitance 8 Ax, Bx
C A, B
f =1MHz, Measured to GND, Code = 80 H
Capacitance Wx
CW
f =1MHz, Measured to GND, Code = 80 H
DIGITAL INPUTS AND OUTPUTS
Input Logic High
V IH
VDD = 5V
Input Logic Low
V IL
VDD = 5V
Input Logic High
V IH
VDD = 3V
Input Logic Low
V IL
VDD = 3V
Input Current
I IH , I IL
V IN = 5V or 0V, VDD = 5V
Input Capacitance
C IL
POWER SUPPLIES
Power Supply Range
VDD
Supply Current (CMOS)
IDD
V IH = VDD or V IL = 0V, VDD = 5.5V
Supply Current (TTL) 9
IDD
V IH = 2.4V or 0.8V, VDD = 5.5V
Power Dissipation
P
V
DISS
IH = VDD or V IL = 0V, VDD = 5.5V
(CMOS) 10
AS1500, Version: 10kΩ
Power Supply Suppression
VDD = 5V + 0.5V P
PSSR
sine wave @ 1kHz
Ratio
AS1501, Version: 20kΩ
DYNAMIC CHARACTERISTICS 11
BW_10k R WB = 10kΩ, VDD = 5V
Bandwidth –3dB
Bandwidth –3dB
BW_20k R WB = 20kΩ, VDD = 5V
Total Harmonic Distortion
THD W
V A = 1V RMS + 2V DC , V B = 2V DC , f = 1kHz
R WB = 5kΩ, V A = VDD, V B = 0V, ±1% Error
t S _10k
Band
V W Settling Time
R WB = 10kΩ, V A = VDD, V B = 0V, ±1% Error
t S _20k
Band
e NWB _10k R WB = 5kΩ, f =1kHz
Resistor Noise Voltage
e NWB _20k R WB = 10kΩ, f =1kHz
Min
Typ 3
Max
Unit
8
16
10
20
500
100
±1/4
±1/2
12
24
kΩ
kΩ
ppm/°C
Ω
LSB
LSB
20
–1
–2
–2
–2
–1
–1
–4
0
8
±1/2
±1/2
±1/4
±1/4
15
–2.8
1.3
0
200
+1
+2
+2
+2
+1
+1
0
2
VDD
75
120
2.4
0.8
2.1
0.6
±1
5
2.7
0.1
0.9
-54
-52
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
LSB
V
pF
pF
V
V
V
V
µA
pF
5.5
1
4
V
µA
mA
27.5
µW
-25
-25
dB
dB
1000
500
0.003
kHz
kHz
%
2
µs
4
µs
9
13
nV/ √ Hz
nV/ √ Hz
Table 3: Electrical Characteristics – 10k and 20k Versions
3
Typicals represent average readings at 25°C and VDD = 5V.
Wiper is not connected. I AB = 350µA for the 10kΩ version and 175µA for the 20kΩ version.
5 All Tempcos are guaranteed by design and not subject to production test.
6 Terminal A is not connected. I W = 350µA for the 10kΩ version and 175µA for the 20kΩ version.
7 Resistor terminals A, B, W have no limitations on polarity with respect to each other.
8 All capacitances are guaranteed by design and not subject to production test. Resistor-terminal capacitance tests are measured with 2.5V
bias on the measured terminal. The remaining resistor terminals are left open circuit.
9 Worst-case supply current consumed when input logic level at 2.4V, standard characteristic of CMOS logic.
10 P DI SS is calculated from (IDD×VDD). CMOS logic level inputs result in minimum power dissipation.
11 All dynamic characteristics are guaranteed by design and not subject to production test. All dynamic characteristics use VDD=5V.
4
Revision 1.0, Oct 2004
Page 3 of 8
Data Sheet AS1500/1/2/3
AS1502 / AS1503 – SPECIFICATIONS
VDD = 3V±10% or 5V±10%, V A = VDD, V B = 0V, –40°C ≤ T A ≤ +125°C unless otherwise noted.
ELECTRICAL CHARACTERISTICS – 50k and 100k VERSIONS
Parameter
Symbol
Conditions
DC CHARACTERISTICS RHEOSTAT MODE
T A = 25°C, VDD = 5V, AS1502, Version: 50kΩ
Nominal Resistance 13
R AB
T A = 25°C, VDD = 5V, AS1503, Version: 100kΩ
Resistance Tempco 14
∆R AB /∆T V AB = VDD, Wiper = No Connect
Wiper Resistance
RW
VDD = 5V
Resistor Differential NL 15
R-DNL R WB , VDD = 5V, V A = No Connect
Resistor Integral NL
R-INL
R WB , VDD = 5V, V A = No Connect
DC CHARACTERISTICS POTENTIOMETER DIVIDER
Resolution
N
VDD = 5.5V T A = 25°C
Integral Nonlinearity
INL
VDD = 2.7V T A = 25°C
VDD = 5.5V T A = 25°C
Differential Nonlinearity
DNL
VDD = 2.7V T A = 25°C
Voltage Divider Tempco
∆V W /∆T Code = 80 H
Full-Scale Error
V WFSE
Code = FF H , VDD = 5.5V
Zero-Scale Error
V WZSE
Code = 00 H , VDD = 5.5V
RESISTOR TERMINALS
Voltage Range 16
V A, B, W
Capacitance 17 Ax, Bx
C A, B
f = 1MHz, Measured to GND, Code = 80 H
Capacitance Wx
CW
f = 1MHz, Measured to GND, Code = 80 H
DIGITAL INPUTS AND OUTPUTS
Input Logic High
V IH
VDD = 5V
Input Logic Low
V IL
VDD = 5V
Input Logic High
V IH
VDD = 3V
Input Logic Low
V IL
VDD = 3V
Input Current
I IH , I IL
V IN = 5V or 0V, VDD = 5V
Input Capacitance
C IL
POWER SUPPLIES
Power Supply Range
VDD
Supply Current (CMOS)
IDD
V IH = VDD or V IL = 0V, VDD = 5.5V
Supply Current (TTL) 18
IDD
V IH = 2.4V or 0.8V, VDD = 5.5V
Power Dissipation
P DISS
V IH = VDD or V IL = 0V, VDD = 5.5V
(CMOS) 19
AS1502, Version: 50kΩ
Power Supply Suppression
VDD = 5V + 0.5V P
PSSR
AS1503, Version:
sine wave @ 1kHz
Ratio
100kΩ
DYNAMIC CHARACTERISTICS 20
BW_50k R WB = 50kΩ, VDD = 5V
Bandwidth –3dB
Bandwidth –3dB
BW_100k R WB = 100kΩ, VDD = 5V
Total Harmonic Distortion
THD W
V A = 1V RMS + 2V DC , V B = 2V DC , f = 1kHz
R WB = 50kΩ, V A = VDD, V B = 0V, ±1% Error
t S _50k
Band
V W Settling Time
R WB = 100kΩ, V A = VDD, V B = 0V, ±1% Error
t S _100k
Band
e NWB _50k R WB = 50kΩ, f = 1kHz
Resistor Noise Voltage
e NWB _100
R WB = 100kΩ, f = 1kHz
k
Min
Typ 12
Max
Unit
40
80
50
100
500
100
±1/4
±1/2
60
120
kΩ
kΩ
ppm/°C
Ω
LSB
LSB
20
–1
–2
–4
–4
–1
–1
–1
0
8
±1
±1
±1/4
±1/4
15
–0.25
0.1
0
200
+1
+2
+4
+4
+1
+1
0
1
VDD
15
80
2.4
0.8
2.1
0.6
±1
5
2.7
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
LSB
V
pF
pF
V
V
V
V
µA
pF
5.5
1
4
V
µA
mA
27.5
µW
-43
tbd.
dB
-48
tbd.
dB
0.1
0.9
220
110
0.003
kHz
kHz
%
9
µs
18
µs
20
nV/ √ Hz
29
nV/ √ Hz
Table 4: Electrical Characteristics – 50k and 100k Versions
Typicals represent average readings at 25°C and VDD = 5V.
Wiper is not connected. I AB = 70µA for the 50kΩ version and 35µA for the 100kΩ version.
14 All Tempcos are guaranteed by design and not subject to production test.
15 Terminal A is not connected. I W = 70µA for the 50kΩ version and 35µA for the 100kΩ version.
16 Resistor terminals A, B, W have no limitations on polarity with respect to each other.
17 All capacitances are guaranteed by design and not subject to production test. Resistor-terminal capacitance tests are measured with 2.5V
bias on the measured terminal. The remaining resistor terminals are left open circuit.
18 Worst-case supply current consumed when input logic level at 2.4V, standard characteristic of CMOS logic.
19 P DI SS is calculated from (IDD×VDD). CMOS logic level inputs result in minimum power dissipation.
20 All dynamic characteristics are guaranteed by design and not subject to production test. All dynamic characteristics use VDD=5V.
12
13
Revision 1.0, Oct 2004
Page 4 of 8
Data Sheet AS1500/1/2/3
AS150x – SPECIFICATIONS
SD
(VDD = 3V±10% or 5V±10%, VA = VDD, VB = 0V,
–40°C≤TA≤+125°C unless otherwise noted.)
CK
ELECTRICAL CHARACTERISTICS–ALL
VERSIONS
CS
1
A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
0
1
0
DAC Register
1
0
VD
SymTyp
Conditions Min 21 Max Unit
bol
SWITCHING CHARACTERISTICS 22, 23
Input Clock
Clock Level
t CH , t CL
50
ns
Pulsewidth
High or Low
Data Setup Time
t DS
5
ns
Data Hold Time
t DH
5
ns
CSN Setup Time
t CSS
10
ns
CSN High
10
ns
t CSW
Pulsewidth
CK Fall to CSN Rise
t CSH
0
ns
Hold Time
CSN Rise to Clock
10
ns
t CS1
Rise Setup
Parameter
Table 5: Switching Characteristics
Serial-Programming
Programming of the AS150x is done via the 3 wire serial
interface. The three input signals are serial data input
(SDI), clock(CK) and chip select (CS). A programming
sequence consists of 10-bit, where the last eight bit
contain the code word for the resistor value. The first two
bits A1 and A0 have to be low(see Table ). The data is
shifted into the internal 10 Bit register with the rising edge
of the CK signal. With the rising edge of the CSN signal
the data becomes valid and the resistance is updated (see
figure 2). A detailed block diagram is shown in figure 3.
D6
D5
D4
D3
Data
Figure 2: Timing Diagram
SDI
1
0
CK
CSN
tD
tD
tC
1
0
1
A X or
A X or
t CS
t CS
t CL
t CS
t CS
0
V DD
V O UT
0V
tS
±1%
±1% Error
Figure 3: Detailed Timing Diagram
Detailed Description
A1 A0 D7
0
0 MSB
V O UT
0V
D2
D1
D0
LSB
Table 6: Serial data format (16 bits)
Rheostat Operation
The digital potentiometer family AS150x offers nominal
resistor values of 10kΩ, 20 kΩ, 50kΩ and 100kΩ. The
resistor has 256 contact points where the wiper can access
the resistor. The 8-bit code word determines the position
of the wiper and is decoded through an internal logic. The
lowest code 00h is related to the terminal B. The
resistance is then only determined by the wiper resistance
(100Ω). The resistance for the next code 01h is the
nominal resistor RAB (10kΩ, 20 kΩ, 50kΩ or 100kΩ)
divided through 256 plus the wiper resistor. In case of
AS1501 (10kΩ) the total resistance is 39Ω+100Ω=139Ω.
Accordingly the resistor for code 02h is 78Ω+100Ω=178Ω.
The last code 255h does not connect to terminal A directly
(see Figure 5). So the maximum value is 10000Ω - 39Ω
+100Ω = 10061Ω. The general formula for the calculation
of the resistance R WB is:
R WB (Dx)= (Dx)/256⋅R AB + R W
21
22
23
Typicals represent average readings at 25°C and VDD=5V.
Guaranteed by design and not subject to production test.
Resistor-terminal capacitance tests are measured with 2.5V
bias on the measured terminal. The remaining resistor
terminals are left open circuit.
See timing diagram for location of measured values. All input
control voltages are specified with t R = t F = 1ns (10% to 90% of
VDD) and timed from a voltage level of 1.6V. Switching
characteristics are measured using VDD=3V or 5V. To avoid
false clocking, a minimum input logic slew rate of 1V/µs should
be maintained.
Revision 1.0, Oct 2004
where R AB is the nominal resistance between terminal A
and B, R W is the wiper resistance and D X is the 8-Bit Code
word. In Table 7 the resistor values between the wiper and
terminal B for AS1501 are given for specific codes D X . In
the zero-scale condition the wiper resistance of 100Ω
remains present.
Page 5 of 8
Data Sheet AS1500/1/2/3
D X (Dec)
R WB (Ω
Ω)
Output State
255
10061
Full Scale
128
5100
Midscale
1
139
1 LSB
0
100
Zero-Scale
(Wiper Contact Resistance)
RS
D7
D6
D5
D4
D3
D2
D1
D0
Table 7: RDAC-Codes WB
The maximum current through the wiper and terminal B is
5mA. If the current exceeds this limit the internal switches
can degrade or even be damaged. As a mechanical
potentiometer the resistance R WA and R W B are totally
symmetrical. The relation between them is shown in Figure
4.
RDAC
LATCH
AND
DECODE
RS
W
RS
B
Figure 5: Equivalent RDAC Circuit
Voltage Output Operation
The AS150x family can easily used in an voltage output
mode, where the output voltage is proportional to an
applied voltage to a given terminal. When 5V are applied to
terminal A and B is set to ground the ouput voltage at the
wiper starts at zero volts up to 1LSB less then 5V. One
LSB of voltage corresponds to the voltage applied at
terminal AB divided through 256 steps of possible wiper
settings. The formula is given by
RW
75
R WA (D), R WB (D) - % of
RS
R S =R NOMI NAL / 256
10
RW
A
50
25
V W (Dx)= (Dx)/256⋅V AB + V B
0
0
64
12
CODE -
19
Figure 4: R WA and R WB versa Code
The resistance RWA is the complimentary resistor to RWB
and can be controlled digitally as well. RWA starts at the
maximum value of the nominal resistance and is reduced
with increasing 8-Bit code words. The formula to calculate
RWA is given below:
R WA (Dx)= (256 - Dx)/256⋅R AB + R W
where R AB is the nominal resistance between terminal A
and B, R W is the wiper resistance and D X is the 8-Bit Code
word. In Table 8 the resistor values between the wiper and
terminal B for AS1501 are given for specific codes D X .
D X (Dec)
255
128
1
0
R WA (Ω
Ω)
89
5050
10011
10050
Output State
Full Scale
Midscale
1 LSB
Zero-Scale
25
where V AB is the voltage applied between terminal A and B,
V W is the voltage at the wiper, D X is the 8-Bit Code word
and V B is the voltage at terminal B. The temperature drift is
significant better than in Rheostat mode, since the
temperature coefficient is determined by the internal
resistor ratio. Therefore the temperature drift is only
15ppm/°C.
Applications
The digital potentiometer can replace in many applications
the analog trimming potentiometer. The digital
potentiometer is not sensitive to vibrations and shocks. It
has an extremely small form-factor and can be adjusted
very fast (e.g. AS1500 has an update rate of 600kHz)
Furthermore the temperature drift, resolution and noise are
significant better and cannot be achieved with a
mechanical trimming potentiometer. Due to the
programmability the resistor settings can be stored in the
system memory, so that after a power down the exact
settings can be recalled easily.
All analog signals must remain within 0 to VDD range. For
standard potentiometer applications the wiper output can
be used directly. In the case of a low impedance load a
buffer shall be used.
Table 8: RDAC-Codes WA
Revision 1.0, Oct 2004
Page 6 of 8
Data Sheet AS1500/1/2/3
Package Information
The AS150x family is offered in a 8-pin SOIC package:
Revision 1.0, Oct 2004
Page 7 of 8
Data Sheet AS1500/1/2/3
Package Dimensions in Inch and mm (values for N = 8 Pin package are valid):
Ordering Information
Part
AS1500
10kΩ
Pin Package Delivery Form
8-pin SOIC
Tubes
AS1501
20kΩ
8-pin SOIC
Tubes
AS1502
50kΩ
8-pin SOIC
Tubes
AS1503
100kΩ
8-pin SOIC
Tubes
AS1500-T
10kΩ
8-pin SOIC
T&R
AS1501-T
20kΩ
8-pin SOIC
T&R
50kΩ
8-pin SOIC
T&R
AS1503-T
100kΩ 8-pin SOIC
For Pb-free package use suffix ‘-Z‘
T&R
AS1502-T
Resistor
Copyright
Revision 1.0, Oct 2004
Copyright © 2004 austriamicrosystems. Trademarks
registered ®. All rights reserved. The material herein may
not be reproduced, adapted, merged, translated, stored, or
used without the prior written consent of the copyright
owner. To the best of its knowledge, austriamicrosystems
asserts that the information contained in this publication is
accurate and correct.
Contact
austriamicrosystems AG
A 8141 Schloss Premstätten, Austria
T. +43 (0) 3136 500 0
F. +43 (0) 3136 525 01
[email protected]
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