ams AS1507-BTDT-100 Dual 256-tap digital potentiometer with spi interface and high endurance eeprom Datasheet

AS1507
D a ta S he e t
D u a l 2 5 6 - Ta p D i g i ta l P o t e n t i o m e t e r w i t h S P I I n t e r f a c e
and High Endurance EEPROM
1 General Description
2 Key Features
The AS1507 is a linear, dual 256-tap digital potentiometer specifically designed to replace discrete/mechanical
potentiometers and is ideal for applications requiring a
low-temperature-coefficient variable resistor.
!
High Endurance: EEPROM up to 10M cycles
!
High Reliability: EEPROM up to 150 years data
retention @ 85°C
The device is controlled via a 3-wire SPI-compatible
interface and features an internal EEPROM for storing
wiper positions.
!
Wiper Position Retained in EEPROM and loaded at
Power-Up
!
256 Tap Positions
!
±0.5LSB DNL in Voltage Divider Mode
!
±0.5LSB INL in Voltage Divider Mode
!
End-to-End Resistance: 10/50/100kΩ
!
Low End-to-End Resistance Temperature
Coefficient: 90ppm/ºC
Several device variants are available differentiated by
end-to-end resistance as shown in Table 1 (see also
Ordering Information on page 16).
Table 1. Standard Products
Model
End-to-End Resistance (kΩ)
AS1507-10
10
AS1507-50
50
!
Low-Power Standby Mode: 100nA
AS1507-100
100
!
5MHz SPI-Compatible Serial Interface
!
Single-Supply Operation: +2.7 to +5.5V
!
TQFN 3x3mm 16-pin Package
The 3-wire SPI-compatible serial interface allows communication at data rates up to 5MHz. The internal
EEPROM stores the last wiper position for initialization
during power-up.
3 Applications
The devices are available in an TQFN 3x3mm 16-pin
package.
The device is ideal for mechanical potentiometer
replacement, low-drift programmable gain amplifiers,
audio volume control, LCD contrast control, and low-drift
programmable filters.
Figure 1. Block Diagram
9
1
READY
15
VDD
8-Bit
Latch
16
8
HIGH A
256-Position
Decoder
MUTE
25
WIPER
2
SCLK
3
SPI
Interface
SDIO
13
PowerOn
Reset
16-Bit
EEPROM
14
LOW A
12
HIGH B
4
CSN
256-Position
Decoder
8-Bit
Latch
25
8
WIPER
10
AS1507
7
11
LOW B
GND
www.austriamicrosystems.com
Revision 1.00
1 - 17
AS1507
Data Sheet - P i n o u t
4 Pinout
Pin Assignments
13 LOW A
14 WIPER A
15 HIGH A
16 MUTE
Figure 2. Pin Assignments (Top View)
VDD 1
12 HIGH B
SCLK 2
11 WIPER B
AS1507
NC 8
9 READY
GND 7
CSN 4
NC 6
10 LOW B
NC 5
SDIO 3
Pin Descriptions
Table 2. Pin Descriptions
Pin Number
1
2
3
4
5, 6, 8
7
9
10
11
12
13
14
15
16
N/A
Pin Name
VDD
SCLK
SDIO
CSN
NC
GND
READY
Description
2.5 to 5.5V Supply Voltage. Bypass with a 0.1µF capacitor to GND.
Serial Clock Input
Serial Data Input
Active-Low Chip Select
Not Connected
Ground
EEPROM Ready. Active-Low indicates an ongoing write operation in the EEPROM.
Low Terminal of Resistor B. The voltage at this pin can be greater than or less
LOW B
than the voltage at pin HIGH. Current can flow into or out of this pin.
Wiper Terminal for Resistor B
WIPER B
High Terminal of Resistor B. The voltage at this pin can be greater than or less
HIGH B
than the voltage at pin LOW. Current can flow into or out of this pin.
Low Terminal of Resistor A. The voltage at this pin can be greater than or less
LOW A
than the voltage at pin HIGH. Current can flow into or out of this pin.
Wiper Terminal for Resistor A
WIPER A
High Terminal of Resistor A. The voltage at this pin can be greater than or less
HIGH A
than the voltage at pin LOW. Current can flow into or out of this pin.
Mute. Both wiper registers are asynchronously set to zero. Data stored in the
EEPROM is not affected. Active-High signal. Internal pull-down resistor. Can be left
MUTE
unconnected if not used.
Exposed Pad The exposed pad is not internally connected. Connect to GND or leave floating.
www.austriamicrosystems.com
Revision 1.00
2 - 17
AS1507
Data Sheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Table 3. Absolute Maximum Ratings
Parameter
Min
Max
Units
VDD to GND
-0.3
+7.0
V
All Other Pins to GND
-0.3
VDD +
0.3
V
AS1507-10
+1
AS1507-50
+1
AS1507-100
+1
Maximum Continuous Current into
Pins HIGH, WIPER, and LOW
Electrostatic Discharge
1
Latch-Up
mA
1
-100
Thermal Resistance ΘJA
100
48
kV
HBM MIL-Std. 883E 3015.7 methods
mA
JEDEC 78
ºC/W
on PCB
Operating Temperature Range
-40
+85
ºC
Storage Temperature Range
-60
+150
ºC
+150
ºC
Junction Temperature
Package Body Temperature
Comments
+260
ºC
The reflow peak soldering temperature
(body temperature) specified is in
accordance with IPC/JEDEC J-STD-020C
“Moisture/Reflow Sensitivity Classification
for Non-Hermetic Solid State Surface
Mount Devices”.
The lead finish for Pb-free leaded
packages is matte tin (100% Sn).
1. The maximum rating voltage must not be exceeded during Latch-up test of the device.
www.austriamicrosystems.com
Revision 1.00
3 - 17
AS1507
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
VDD = +2.7 to +5.5V, HIGH = VDD, LOW = GND, TAMB = -40 to +85ºC. Typ values are at VDD = +5.0V, TAMB = +25ºC
(unless otherwise specified).
Table 4. Electrical Characteristics
Symbol
Power Supply
VDD
IDD
Parameter
Condition
Min
Typ
Max
Unit
0.1
5.5
0.5
V
µA
110
200
µA
±0.5
±0.25
±1
±0.5
LSB
AS1507-10
AS1507-50 & -100
±0.5
±0.25
±1
±0.5
LSB
TAMB = 0 to +85ºC
90
AS1507-10
AS1507-50
AS1507-100
AS1507-10
AS1507-50
AS1507-100
2.5
1.5
1.5
1
0.1
0.1
4
2.5
2.5
2
0.7
0.7
AS1507-10
AS1507-50 & -100 @ 3V
AS1507-50 & -100 @ 5V
AS1507-10
AS1507-50 & -100
±1
±0.6
±0.5
±0.5
±0.5
±2
±1.5
±1
±1
±1
VDD = 3V
VDD = 5V
200
120
15
10
50
100
2.70
Standby Current
Digital Inputs = VDD or GND, TAMB = +25ºC
Operating Current
1
IOP
Includes Non-Volatile Write to Memory
(CMOS write)
DC Performance (Voltage Divider Mode)
N
Resolution
AS1507-10
2
INL
Integral Linearity
AS1507-50 & -100
DNL
Differential Non-Linearity
TCR
End-to-End Resistance
Temperature Coefficient
2
Full Scale Error
Zero Scale Error
256
Taps
ppm/ºC
LSB
LSB
DC Performance (Variable Resistor Mode)
INL
DNL
Integral Linearity
3
Differential Non-Linearity
LSB
LSB
DC Performance (Resistor Characteristics)
4
RW
Wiper Resistance
CW
Wiper Capacitance
REE
AS1507-10
AS1507-50
AS1507-100
End-to-End Resistance
Inputs and Outputs
WIPER Voltage Range
HIGH Voltage Range
LOW Voltage Range
VIH
Digital Input High Voltage
VIL
Digital Input Low Voltage
ILEAK
CIN
ICONT
GND0.3
5
5
VDD = 3V
VDD = 5V
VDD = 3V
VDD = 5V
Digital Input Leakage Current
Digital Input Capacitance
Continuous DAC current
www.austriamicrosystems.com
7.5
37.5
75
Ω
pF
12.5
62.5
125
kΩ
VDD+
0.3
V
2.1
2.4
V
200
5
0.6
0.8
500
1000
Revision 1.00
V
nA
pF
µA
4 - 17
AS1507
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Table 4. Electrical Characteristics (Continued)
Symbol
Parameter
Condition
Min
Typ
Max
Unit
Dynamic Characteristics
Wiper -3dB Bandwidth
tS
6
7
Wiper Settling Time
AS1507-10
AS1507-50
AS1507-100
AS1507-10
AS1507-50
AS1507-100
1200
220
120
1100
1600
2200
TAMB = +85ºC
150
Years
TAMB = +25ºC
TAMB = +85ºC
10M
1M
Write
Cycles
kHz
ns
Non-Volatile Memory Reliability
Data Retention
Endurance
tBUSY
8
8
Write Non-Volatile Register
Busy Time
20
ms
1. The programming current operates only during power-up and non-volatile memory writes.
2. DNL and INL are measured with the potentiometer configured as a voltage-divider with HIGH = VDD and LOW =
GND. The wiper terminal is unloaded and measured with a high-input-impedance voltmeter.
3. DNL and INL are measured with the potentiometer configured as a variable resistor. HIGH is unconnected and
LOW = GND. For the 5V condition, the wiper terminal is driven with a source current of 400µA @ 10kΩ, 80µA @
50kΩ, 40µA @ 100kΩ. In 3V conditions, the wiper terminal is driven with a source current of 200µA @ 10kΩ,
40µA @ 50kΩ, 20µA @ 100kΩ.
4. The wiper resistance is measured using the source currents given in Note 3. The number is the worst case
resistance over TAP positions.
5. The device draws higher supply current when the digital inputs are driven with voltages between (VDD - 0.5V)
and (GND + 0.5V).
6. Wiper at midscale with a 10pF load (DC measurement) VDD = 5V, LOW = GND. An AC source (5V peak to peak
sinus signal) is applied to HIGH and the WIPER output is measured. A 3dB bandwidth occurs when the AC
WIPER/HIGH value is 3dB lower than the DC WIPER/HIGH value.
7. Wiper-settling time is the worst-case 0 to 50% rise-time measured between successive wiper positions. HIGH =
VDD, LOW = GND; WIPER is unloaded and measured with a 10pF load.
8. This parameter is not tested but ensured by characterization.
Timing Characteristics
VDD = +2.7 to +5.5V, HIGH = VDD, LOW = GND, TAMB = -40 to +85ºC. Typ values are at VDD = +5.0V, TAMB = +25ºC
(unless otherwise specified). See Figure 20 on page 9. Digital timing data is guaranteed by design and characterization, and is not production tested.
Table 5. Timing Characteristics
Symbol
fSCLK
tCP
tCH
tCL80
tCSS
tCSH
tDS
tDH
tCS0
tCS1
tCSW
tBUSY
Parameter
SCLK Frequency
SCLK Clock Period
SCLK Pulse-Width High
SCLK Pulse-Width Low
CSN-Fall to SCLK Rise Setup
SCLK-Rise to CSN-Rise Hold
SDIO to SCLK Setup
SDIO Hold after SCLK
SCLK-Rise to CSN-Fall Delay
CSN-Rise to SCLK-Rise Hold
CSN Pulse-Width High
Write Non-Volatile Register Busy Time
www.austriamicrosystems.com
Condition
Min
Typ
Max
5
200
40
40
40
40
10
0
40
40
200
20
Revision 1.00
Unit
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ms
5 - 17
AS1507
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
7 Typical Operating Characteristics
VDD = 5V (unless otherwise specified).
Figure 4. INL vs. TAP Position 10kΩ, Divider Mode
1
1
0.8
0.8
0.6
0.6
0.4
0.4
INL (LSB) .
DNL (LSB) .
Figure 3. DNL vs. TAP Position 10kΩ, Divider Mode
0.2
0
-0.2
0.2
0
-0.2
-0.4
-0.4
-0.6
-0.6
-0.8
-0.8
-1
-1
0
32
64
0
96 128 160 192 224 256
32
64
Figure 6. INL vs. TAP Position 50kΩ, Divider Mode
0.5
0.5
0.4
0.4
0.3
0.3
0.2
0.2
INL (LSB) .
DNL (LSB) .
Figure 5. DNL vs. TAP Position 50kΩ, Divider Mode
0.1
0
-0.1
0.1
0
-0.1
-0.2
-0.2
-0.3
-0.3
-0.4
-0.4
-0.5
-0.5
0
32
64
96 128 160 192 224 256
0
32
64
Tap Position
Figure 8. INL vs. TAP Position 100kΩ, Divider Mode
0.5
0.4
0.4
0.3
0.3
0.2
0.2
INL (LSB) .
0.5
0.1
0
-0.1
0.1
0
-0.1
-0.2
-0.2
-0.3
-0.3
-0.4
-0.4
-0.5
96 128 160 192 224 256
Tap Position
Figure 7. DNL vs. TAP Position 100kΩ, Divider Mode
DNL (LSB) .
96 128 160 192 224 256
Tap Position
Tap Position
-0.5
0
32
64
96 128 160 192 224 256
0
Tap Position
www.austriamicrosystems.com
32
64
96 128 160 192 224 256
Tap Position
Revision 1.00
6 - 17
AS1507
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 10. INL vs. TAP Position 10kΩ, Varistor Mode
1
2
0.8
1.6
0.6
1.2
0.4
0.8
INL (LSB) .
DNL (LSB) .
Figure 9. DNL vs. TAP Position 10kΩ, Varistor Mode
0.2
0
-0.2
0.4
0
-0.4
-0.4
-0.8
-0.6
-1.2
-0.8
-1.6
-1
-2
0
32
64
96 128 160 192 224 256
0
32
64
Tap Position
Figure 12. INL vs. TAP Position 50kΩ, Varistor Mode
1
1
0.8
0.8
0.6
0.6
0.4
0.4
INL (LSB) .
DNL (LSB) .
Figure 11. DNL vs. TAP Position 50kΩ, Varistor Mode
0.2
0
-0.2
0.2
0
-0.2
-0.4
-0.4
-0.6
-0.6
-0.8
-0.8
-1
-1
0
32
64
96 128 160 192 224 256
0
32
64
Tap Position
Figure 14. INL vs. TAP Position 100kΩ, Varistor
1
0.8
0.8
0.6
0.6
0.4
0.4
INL (LSB) .
1
0.2
0
-0.2
96 128 160 192 224 256
Tap Position
Figure 13. DNL vs. TAP Position 100kΩ, Varistor Mode
Mode
DNL (LSB) .
96 128 160 192 224 256
Tap Position
0.2
0
-0.2
-0.4
-0.4
-0.6
-0.6
-0.8
-0.8
-1
-1
0
32
64
0
96 128 160 192 224 256
www.austriamicrosystems.com
32
64
96 128 160 192 224 256
Tap Position
Tap Position
Revision 1.00
7 - 17
AS1507
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 15. Wiper Resistance vs. TAP; 5V
Figure 16. Wiper Resistance vs. TAP; 3V
120
180
160
.
80
Resistance (Ω )
Resistance (Ω)
.
100
60
40
140
120
100
80
60
40
20
20
0
0
0
32
64
96 128 160 192 224 256
0
32
64
Tap Position
96 128 160 192 224 256
Tap Position
Figure 17. DAC Resistor vs. Temperature
Figure 18. Gain vs. Bandwidth
0
118
117
Gain (dB) .
Resistance (kΩ)
.
100kΩ
-3
116
115
114
113
50kΩ
10kΩ
-6
-9
112
111
-12
110
25
35
45
55
65
75
1
85
10
100
1000
10000
Frequency (kHz)
Temperature (°C)
Figure 19. EEPROM Data Retention vs. Temperature
Data Retension (years)
.
10000
1000
100
10
25
45
65
85
105
125
Temperature (°C)
www.austriamicrosystems.com
Revision 1.00
8 - 17
AS1507
Data Sheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1507 contains two resistor arrays with 255 resistive elements each (tap points), and has a total end-to-end
resistance of 10, 50, or 100kΩ (see Ordering Information on page 16).
The device provides high, low, and wiper terminals for a standard voltage-divider configuration. Pins HIGH, LOW, and
WIPER can be connected in any configuration as long as their voltages fall between GND and VDD.
A 3-wire, SPI-compatible serial interface controls movement of the wiper among the 256 tap points. The EEPROM
stores the wiper position and recalls the stored wiper position upon power-up. The EEPROM typically holds wiper data
for 150 years and up to 10M wiper store cycles.
Analog Circuit
The 256 tap points are accessible to the wiper along the resistor string between pins HIGH and LOW (similar to the
end terminals of a mechanical potentiometer). The wiper tap point is selected by programming 8 data bits and a control
byte via the 3-wire serial interface (see Programming the Device on page 10).
Note: Integrated power-on reset circuitry loads the wiper position from the EEPROM at power-up.
Digital Interface
The AS1507 uses an SPI-compatible 3-wire interface for command settings of the device consisting of two input signals (chip-select - CSN, and data clock - SCLK) and one bi-directional data pin (SDIO). Driving CSN low enables serial
interface and the command/data are passed into the device synchronously by each SCLK rising edge.
There are 16-bit commands for write data into the wiper register or the non-volatile memory, and 8-bit commands for
transferring data between wiper register and non-volatile memory and to read the data stored in the wiper register or
non-volatile memory. The 8-bit commands can be implemented in 16-bit command structure alternatively. In this case
the first 8 bits shifted through the SPI interface are not significant. The data byte passed at writing commands represents the position of the wiper.
After loading the 8- or 16-bit command while CSN is low, the loaded command is executed at the next rising edge of
CSN, simultaneously the serial interface is disabled. The CSN signal must be low during the whole serial input stream
through the SPI, otherwise data on the SPI interface are corrupted.
Note: If the data-in stream does not exactly contain 8 or 16 digits, no command is executed at the rising edge of
CSN.
Figure 20. Serial Data Timing
...
CSN
tCSW
tCS0
tCL
tCSS
tCS1
tCH
tCP
tCSH
...
SCLK
tDS
tDH
...
SDIO
Standby Mode
Low-power standby mode is enabled at CSN high. After a read access standby mode is entered 2 cycles of SCLK
after issuing the last bit of the data wiper or non-volatile register. If the digital inputs are stable VDD or GND there is only
leakage power dissipation of the device.
This power dissipation is defined with 0.1uA (typ) at 25ºC.
www.austriamicrosystems.com
Revision 1.00
9 - 17
AS1507
Data Sheet - D e t a i l e d D e s c r i p t i o n
EEPROM (Non-Volatile Register)
There is an internal EEPROM register implemented to retain the wiper position after power down. During an ongoing
write cycle of the non-volatile register (tBUSY time) the system must not be powered down. A write cycle on the
EEPROM is indicated by the READY signal.
Data retention defines the ability of an EEPROM to retain data over time. The qualification has been done according to
JEDEC Retention Lifetime Specification (A117). The EEPROM is cycled to the specified endurance limit before the
data retention test is done. Based on activation energy of 0.6eV the data retention time derates over temperature as
shown in Figure 19 on page 8.
For the non-volatile register 1M endurance cycles and a data retention of 150 years are typical at 85 ºC. The non-volatile register is factory trimmed to mid-scale.
Power-Up
The AS1507 contains an integrated power-up circuit. At power up, the data are transferred from the non-volatile memory to the wiper register. The wiper register moves to the stored position. This data transfer takes 5µs after the supply
has reached the POR trigger level.
Programming the Device
Write commands (see Table 6) require 16 clock cycles (see Figure 22 on page 12) to clock in the command and data.
Copy and Read commands (see Table 6) can use 8 clock cycles to clock in the command (see Figure 21 on page 12)
or 16 clock cycles. At 16 clock cycle commands the 8 data bits (D7:D0) are insignificant.
Table 6. Command/Data Word Format
Command
Write Wiper Register A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
C7
C6
C5
C4
C3
C2
C1
C0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
1
D7
D6
D5
D4
D3
D2
D1
D0
Write Wiper Register B
0
0
0
0
0
0
1
0
D7
D6
D5
D4
D3
D2
D1
D0
Write both Wiper Registers
0
0
0
0
0
0
1
1
D7
D6
D5
D4
D3
D2
D1
D0
Write to Non-Volatile
Register A
0
0
0
1
0
0
0
1
D7
D6
D5
D4
D3
D2
D1
D0
Write to Non-Volatile
Register B
0
0
0
1
0
0
1
0
D7
D6
D5
D4
D3
D2
D1
D0
Write to both Non-Volatile
Registers
0
0
0
1
0
0
1
1
D7
D6
D5
D4
D3
D2
D1
D0
Copy Wiper Register A to NonVolatile Register
0
0
1
0
0
0
0
1
-
-
-
-
-
-
-
-
Copy Wiper Register B to NonVolatile Register
0
0
1
0
0
0
1
0
-
-
-
-
-
-
-
-
Copy Both Wiper Registers to
Non-Volatile Registers
0
0
1
0
0
0
1
1
-
-
-
-
-
-
-
-
Copy Non-Volatile Register A
to Wiper Register
0
0
1
1
0
0
0
1
-
-
-
-
-
-
-
-
Copy Non-Volatile Register B
to Wiper Register
0
0
1
1
0
0
1
0
-
-
-
-
-
-
-
-
Copy Both Non-Volatile
Registers
to Wiper Registers
0
0
1
1
0
0
1
1
-
-
-
-
-
-
-
-
www.austriamicrosystems.com
Revision 1.00
10 - 17
AS1507
Data Sheet - D e t a i l e d D e s c r i p t i o n
Commands
Write Wiper Register
This is a 16-bit command (see Figure 22 on page 12). The first byte represents the command word starting with the
MSB bit of the command, the second byte represents the data written to the wiper register (starting with the MSB).
Data 0000 0000 the wiper moves the closest position to LOW, with data 1111 1111 the wiper moves to the closest position to HIGH. The wiper registers can be written independently in two write cycles with different data or in one write
cycle with the same data.
Note: At power-up the wiper position stored in the non-volatile memory are automatically loaded into the wiper register, the wiper moves to the related position.
Write to Non-Volatile Register
This is a 16-bit command (see Figure 22 on page 12). The first byte represents the command word starting with the
MSB bit of the command, the second byte represents the data written to the non-volatile memory. The wiper position is
not changed by this command, since the wiper register is not affected. The non-volatile registers can be written independently in two write cycles with different data or in one write cycle with the same data.
There is a write non-volatile register time defined in the timing specification, which is required for storing the data in the
non-volatile register. The READY pin indicates the write time with an active-low signal. During this time the device
must not be powered down, otherwise the data stored in the non-volatile register is corrupted.
Copy Wiper Register to Non-Volatile Register
This command can be implemented as an 8- or 16-bit command. The data stored in the wiper register are transferred
to the non-volatile memory, to keep the data during power-down. There is no automatic trigger of this command during
power-down of the device. This command must be triggered before powering down the device.
There is a write non-volatile register time defined in the timing specification, which is required for storing the data in the
non-volatile register. During this time the device must not be powered down, otherwise the data stored in the non-volatile register is corrupted.
Copy Non-Volatile Register to Wiper Register
This command can be implemented as an 8- or 16-bit command. The data stored in the non-volatile register are transferred to the wiper register, the wiper register moves to the stored position. This command is automatically executed
during power up of the system.
Read Non-Volatile Register
The AS1507 features the capability to read the data from the non-volatile register via the SPI interface (see Figure 23
on page 12). This command can be implemented as an 8- or 16-bit command. The SDIO pin is a bi-directional pin.
During the CSN low phase of the sequence the SDIO pin is used as input pin to set the command byte. After CSN rising edge the pin SDIO is set as output pin, the data stored in the non-volatile register are read serially, MSB first.
The data propagation starts at the second rising edge of SCLK after the rising edge of CSN. CSN must be high during
the read operation. With the next falling edge of CSN the SDIO pin is set to an input pin again.
Read Wiper Register
The AS1507 features the capability to read the data from the wiper register via the SPI interface (see Figure 23 on
page 12). This command can be implemented as an 8- or 16-bit command. The SDIO pin is a bi-directional pin. During
the CSN low phase of the sequence, the SDIO pin is used as input pin to set the command byte. After CSN rising edge
the pin SDIO is set as output pin, the data stored in the wiper register are read serially, MSB first. The wiper position is
unchanged.
The data propagation starts at the second rising edge of SCLK after the rising edge of CSN. CSN must be high during
the read operation. With the next falling edge of CSN the SDIO pin is set to an input pin again.
Mute Command
When a high signal is applied on the MUTE pin both wiper positions are set to zero permanently. While in mute operation SPI commands to wiper registers are not executed. Data stored in non-volatile registers are not affected by the
mute command. The MUTE pin includes a pull-down resistor. If a mute function is not required the pin can be left
unconnected.
www.austriamicrosystems.com
Revision 1.00
11 - 17
AS1507
Data Sheet - D e t a i l e d D e s c r i p t i o n
Figure 21. 8-Bit Command Word
CSN
SCLK
SDIO
C7
C6
C5
C4
C3
C2
C1
C0
Figure 22. 16-Bit Command/Data Word
CSN
SCLK
SDIO
C7
C6
C5
C4
C3
C2
C1
C0
D7
D6
D5
D4
D3
D2
D1
D0
Figure 23. 16-Bit Read Command
CSN
SCLK
SDIO
C7
C6
C5
C4
C3
C2
C1
C0
D7
D6
D5
D4
D3
D2
D1
D0
Figure 24. 16-Bit EEPROM Write Command
CSN
SCLK
SDIO
0
0
0
1
0
0
C1
C0
D7
D6
D5
D4
D3
D2
D1
D0
tBUSY
READY
www.austriamicrosystems.com
Revision 1.00
12 - 17
AS1507
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
The AS1507 is intended for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control
(where voltage biasing adjusts the display contrast), or programmable filters with adjustable gain and/or cutoff frequency.
Programmable Filter
Figure 25 shows the configuration for a 1st-order programmable filter.
The DC gain of the filter is adjusted by R2 and can be calculated as:
G = 1 + (R1/R2)
(EQ 1)
The cutoff frequency (fC) is adjusted by R3, and can be calculated as:
fC = 1/(2π x R3 x C)
(EQ 2)
Figure 25. Programmable Filter Circuit
CIN
VIN
+
VOUT
–
R1
HIGHB
HIGHA
WIPERA
R3
R2
AS1507
LOWA
WIPERB
LOWB
Offset Voltage and Gain Adjustment
Connect one potentiometer of the AS1507 to an op amp to nullify the offset voltage over the operating temperature
range. Use the second potentiometer in the feedback path to adjust the gain of the op amp (Figure 26).
Figure 26. Offset Voltage and Gain Adjustment Circuit
5V
+
–
HIGHA
WIPERA
LOWA
www.austriamicrosystems.com
HIGHB
AS1507
WIPERB
LOWB
Revision 1.00
13 - 17
AS1507
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
Positive LCD Bias Control
The device can be used in applications where a voltage-divider or variable resistor is used to make an adjustable, positive LCD-bias voltage, such as for the AS1120 LCD Driver. The op amp provides buffering and gain to the resistordivider network made by the potentiometer (Figure 27) or to a fixed resistor and a variable resistor (Figure 28).
Figure 27. Positive LCD Bias Control using a Voltage Divider
5V
HIGH
30V
AS1507
WIPER
LOW
+
VOUT
–
Figure 28. Positive LCD Bias Control using a Variable Resistor
5V
30V
+
VOUT
–
HIGH
AS1507
WIPER
LOW
Adjustable Voltage Reference
Figure 29 shows the device used as the feedback resistor in an adjustable voltage-reference application. Output voltages of external voltage references, supervisory reset thresholds, or LED brightness control can be independently
adjusted by changing the wiper position of the AS1507.
Figure 29. Adjustable Voltage Reference Circuit – VOUT = 1.23V(50kΩ/R2(kΩ)
5V
VIN
VIN
VOUTREF1
OUT
HIGHA
ADJ
WIPERA
HIGHB
AS1507
ADJ
LOWA
www.austriamicrosystems.com
VOUTREF
OUT
WIPERB
AS1507
LOWB
Revision 1.00
14 - 17
AS1507
Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
10 Package Drawings and Markings
The device is available in an TQFN 3x3mm 16-pin package.
Figure 30. TQFN 3x3mm 16-pin Package
Symbol
A
A1
L
L1
K
aaa
bbb
ccc
ddd
Min
0.70
0.00
0.30
0.03
0.20
Typ
0.75
0.02
0.40
0.10
0.10
0.10
0.05
Max
0.80
0.05
0.50
0.15
Notes
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2
Symbol
D BSC
E BSC
D2
E2
θ
b
e
N
ND
Min
1.55
1.55
0º
0.18
Typ
3.00
3.00
1.70
1.70
0.25
0.5
16
4
Max
1.80
1.80
14º
0.30
Notes
1, 2
1, 2
1, 2
1, 2
1, 2
1, 2, 5
1, 2
1, 2, 5
Notes:
1.
2.
3.
4.
Dimensioning and tolerancing conform to ASME Y14.5M-1994.
All dimensions are in millimeters, angle is in degrees.
N is the total number of terminals.
Terminal #1 identifier and terminal numbering convention shall conform to JESD 95-1 SPP-012. Details of terminal #1 identifier are optional, but must be located within the area indicated. The terminal #1 identifier may be
either a mold, embedded metal or mark feature.
5. Dimension b applies to metallized terminal and is measured between 0.15 and 0.30mm from terminal tip.
6. ND refers to the maximum number of terminals on D side.
7. Unilateral coplanarity zone applies to the exposed heat sink slug as well as the terminals.
www.austriamicrosystems.com
Revision 1.00
15 - 17
AS1507
Data Sheet
11 Ordering Information
The device is available as the standard products shown in Table 7.
Table 7. Ordering Information
Model
Marking
Description
End-to-End
Resistance
Delivery Form
Package
AS1507-BTDT-10
ASPF
Dual 256-Tap, Non-Volatile,
SPI Digital Potentiometer
10kΩ
Tape and Reel
TQFN 3x3mm 16pin
AS1507-BTDT-50
ASPE
Dual 256-Tap, Non-Volatile,
SPI Digital Potentiometer
50kΩ
Tape and Reel
TQFN 3x3mm 16pin
AS1507-BTDT-100
ASPD
Dual 256-Tap, Non-Volatile,
SPI Digital Potentiometer
100kΩ
Tape and Reel
TQFN 3x3mm 16pin
www.austriamicrosystems.com
Revision 1.00
16 - 17
AS1507
Data Sheet - O r d e r i n g I n f o r m a t i o n
Copyrights
Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
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.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing
in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding
the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for
each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to
personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or
consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of
austriamicrosystems AG rendering of technical or other services.
Contact Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstaetten, Austria
Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
www.austriamicrosystems.com
Revision 1.00
17 - 17
Similar pages