SLIS135E December   2010  – February 2017

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Operating Characteristics
    7. 6.7 SPI Timing Requirements
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Dual Channel, 256-Position Resolution
      2. 7.3.2 Non-Volatile Memory
    4. 7.4 Device Functional Modes
      1. 7.4.1 Voltage Divider Mode
      2. 7.4.2 Rheostat Mode
      3. 7.4.3 Ideal Resistance Values
    5. 7.5 Programming
      1. 7.5.1 SPI Digital Interface
    6. 7.6 Register Map
      1. 7.6.1 Digital Interface Format
      2. 7.6.2 Write-Wiper Register (Command 00)
      3. 7.6.3 Write-NV Register (Command 01)
      4. 7.6.4 Copy Wiper Register to NV Register (Command 10)
      5. 7.6.5 Copy NV Register to Wiper Register (Command 11)
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
    1. 9.1 Power Sequence
    2. 9.2 Wiper Position Upon Power Up
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Detailed Description

7.1 Overview

The TPL0202 has two linear-taper digital potentiometers with 256 wiper positions and an end-to-end resistance of 100 kΩ. Each potentiometer can be used as a three-terminal potentiometer or as a two-terminal rheostat. The two potentiometers can both be used in voltage divider mode or rheostat mode at the same time, or any combination of those modes. For example, potentiometer A can be used in voltage divider mode and potentiometer B can be used in rheostat mode. The two potentiometers are functionally independent of one another.

The high (H) and low (L) terminals of the TPL0202 are equivalent to the fixed terminals of a mechanical potentiometer. The H and L terminals do not have any polarity restrictions (H can be at a higher voltage than L, or L can be at a higher voltage than H). The position of the wiper (W) terminal is controlled by the value in the Wiper Resistance (WR) 8-bit register. When the WR register contains all zeroes (zero-scale), the wiper terminal is closest to its L terminal. As the value of the WR register increases from all zeroes to all ones (full-scale), the wiper moves from the position closest to the L terminal, to the position closest to the H terminal. At the same time, the resistance between W and L increases, whereas the resistance between W and H decreases.

The TPL0202 has non-volatile memory (EEPROM) that can be used to store the wiper position. When the device is powered down, the last value copied in the non-volatile memory (NVM) will be maintained. When power is restored, the contents of the NVM are automatically recalled and loaded into the corresponding wiper register to set the wipers. The internal registers of the TPL0202 can be written to using a SPI-compatible interface. The factory-programmed default value for the NVM is 0x80h (1000 0000). The wiper registers (volatile memory) and the NVM registers can be written to independently without having to modify the current value in another register. See the Register Map section for more information.

7.2 Functional Block Diagram

TPL0202 fbd_LIS135.gif

7.3 Feature Description

7.3.1 Dual Channel, 256-Position Resolution

The TPL0202 features two independent DPOTs. Each DPOT is capable of being used and controlled independently of the other one.

7.3.2 Non-Volatile Memory

The TPL0202 device features non-volatile memory which is used to store the wiper positions of both potentiometers independently. This allows the user to set the default power-up position of the wiper. By default, this is 0x80h (midscale).

7.4 Device Functional Modes

7.4.1 Voltage Divider Mode

The digital potentiometer generates a voltage divider when all three terminals are used. The voltage divider at wiper-to-H and wiper-to-L is proportional to the input voltage at H to L.

TPL0202 dfm_vt_mode_slis134.gif Figure 22. Equivalent Circuit for Voltage Divider Mode

For example, connecting terminal H to 5 V and terminal L to ground, the output voltage at terminal W can range from 0 V to 5 V. The general equation defining the output voltage at terminal W for any valid input voltage applied to terminal H and terminal L is:

Equation 1. TPL0202 eq1_slis134.gif

The voltage difference between terminal H and terminal W can also be calculated using Equation 2.

Equation 2. TPL0202 eq2_slis134.gif

where

  • D is the decimal value of the wiper code.

7.4.2 Rheostat Mode

The TPL0202 operates in rheostat mode when only two terminals are used as a variable resistor. The variable resistance can either be between terminal H and terminal W or between terminal L and terminal W.  The unused terminal can be left floating or it can be tied to terminal W. The nominal resistance between terminal H and terminal L is 10 kΩ and has 256 tap points accessed by the wiper terminal. The 8-bit volatile register value is used to determine one of the 256 possible wiper positions.

To set the resistance between terminal H and terminal W in rheostat mode, the potentiometer can be configured in two possible ways.

TPL0202 dfm_rheostat_m1_slis134.gif Figure 23. Equivalent Circuit for Rheostat Mode With Terminal H to Terminal W Resistance

The general equation for determining the digitally-programmed output resistance between terminal H and terminal W is:

Equation 3. TPL0202 eq3_slis134.gif

where

  • RTOT is the end-to-end resistance between terminal H and terminal L.
  • D is the decimal value of the wiper code.

Similarly, to set the resistance between terminal L and terminal W, the potentiometer can be configured in two possible ways.

TPL0202 dfm_rheostat_m2_slis134.gif Figure 24. Equivalent Circuit for Rheostat Mode With Terminal L to Terminal W Resistance

The general equation for determining the digitally-programmed output resistance between terminal L and terminal W is:

Equation 4. TPL0202 eq4_slis134.gif

where

  • RTOT is the end-to-end resistance between terminal H and terminal L.
  • D is the decimal value of the wiper code.

7.4.3 Ideal Resistance Values

TPL0202 resval_fig.gif Figure 25. Digital Potentiometer Measurements

Table 1 shows the ideal values for DPOT with end-to-end resistance of 10 kΩ. The absolute values of resistance can vary significantly, but the ratio (RWL / RHW) is extremely accurate.

Table 1. Ideal Values for DPOT

STEP BINARY HEX 10 kΩ RWL / RHW
RWL RHW
0 00000000 00 0.00 10.00 0.00
1 00000001 01 0.04 9.96 0.00
2 00000010 02 0.08 9.92 0.01
3 00000011 03 0.12 9.88 0.01
4 00000100 04 0.16 9.84 0.02
5 00000101 05 0.20 9.80 0.02
6 00000110 06 0.23 9.77 0.02
7 00000111 07 0.27 9.73 0.03
8 00001000 08 0.31 9.69 0.03
9 00001001 09 0.35 9.65 0.04
10 00001010 0A 0.39 9.61 0.04
11 00001011 0B 0.43 9.57 0.04
12 00001100 0C 0.47 9.53 0.05
13 00001101 0D 0.51 9.49 0.05
14 00001110 0E 0.55 9.45 0.06
15 00001111 0F 0.59 9.41 0.06
16 00010000 10 0.63 9.38 0.07
17 00010001 11 0.66 9.34 0.07
18 00010010 12 0.70 9.30 0.08
19 00010011 13 0.74 9.26 0.08
20 00010100 14 0.78 9.22 0.08
21 00010101 15 0.82 9.18 0.09
22 00010110 16 0.86 9.14 0.09
23 00010111 17 0.90 9.10 0.10
24 00011000 18 0.94 9.06 0.10
25 00011001 19 0.98 9.02 0.11
26 00011010 1A 1.02 8.98 0.11
27 00011011 1B 1.05 8.95 0.12
28 00011100 1C 1.09 8.91 0.12
29 00011101 1D 1.13 8.87 0.13
30 00011110 1E 1.17 8.83 0.13
31 00011111 1F 1.21 8.79 0.14
32 00100000 20 1.25 8.75 0.14
33 00100001 21 1.29 8.71 0.15
34 00100010 22 1.33 8.67 0.15
35 00100011 23 1.37 8.63 0.16
36 00100100 24 1.41 8.59 0.16
37 00100101 25 1.45 8.55 0.17
38 00100110 26 1.48 8.52 0.17
39 00100111 27 1.52 8.48 0.18
40 00101000 28 1.56 8.44 0.19
41 00101001 29 1.60 8.40 0.19
42 00101010 2A 1.64 8.36 0.20
43 00101011 2B 1.68 8.32 0.20
44 00101100 2C 1.72 8.28 0.21
45 00101101 2D 1.76 8.24 0.21
46 00101110 2E 1.80 8.20 0.22
47 00101111 2F 1.84 8.16 0.22
48 00110000 30 1.88 8.13 0.23
49 00110001 31 1.91 8.09 0.24
50 00110010 32 1.95 8.05 0.24
51 00110011 33 1.99 8.01 0.25
52 00110100 34 2.03 7.97 0.25
53 00110101 35 2.07 7.93 0.26
54 00110110 36 2.11 7.89 0.27
55 00110111 37 2.15 7.85 0.27
56 00111000 38 2.19 7.81 0.28
57 00111001 39 2.23 7.77 0.29
58 00111010 3A 2.27 7.73 0.29
59 00111011 3B 2.30 7.70 0.30
60 00111100 3C 2.34 7.66 0.31
61 00111101 3D 2.38 7.62 0.31
62 00111110 3E 2.42 7.58 0.32
63 00111111 3F 2.46 7.54 0.33
64 01000000 40 2.50 7.50 0.33
65 01000001 41 2.54 7.46 0.34
66 01000010 42 2.58 7.42 0.35
67 01000011 43 2.62 7.38 0.35
68 01000100 44 2.66 7.34 0.36
69 01000101 45 2.70 7.30 0.37
70 01000110 46 2.73 7.27 0.38
71 01000111 47 2.77 7.23 0.38
72 01001000 48 2.81 7.19 0.39
73 01001001 49 2.85 7.15 0.40
74 01001010 4A 2.89 7.11 0.41
75 01001011 4B 2.93 7.07 0.41
76 01001100 4C 2.97 7.03 0.42
77 01001101 4D 3.01 6.99 0.43
78 01001110 4E 3.05 6.95 0.44
79 01001111 4F 3.09 6.91 0.45
80 01010000 50 3.13 6.88 0.45
81 01010001 51 3.16 6.84 0.46
82 01010010 52 3.20 6.80 0.47
83 01010011 53 3.24 6.76 0.48
84 01010100 54 3.28 6.72 0.49
85 01010101 55 3.32 6.68 0.50
86 01010110 56 3.36 6.64 0.51
87 01010111 57 3.40 6.60 0.51
88 01011000 58 3.44 6.56 0.52
89 01011001 59 3.48 6.52 0.53
90 01011010 5A 3.52 6.48 0.54
91 01011011 5B 3.55 6.45 0.55
92 01011100 5C 3.59 6.41 0.56
93 01011101 5D 3.63 6.37 0.57
94 01011110 5E 3.67 6.33 0.58
95 01011111 5F 3.71 6.29 0.59
96 01100000 60 3.75 6.25 0.60
97 01100001 61 3.79 6.21 0.61
98 01100010 62 3.83 6.17 0.62
99 01100011 63 3.87 6.13 0.63
100 01100100 64 3.91 6.09 0.64
101 01100101 65 3.95 6.05 0.65
102 01100110 66 3.98 6.02 0.66
103 01100111 67 4.02 5.98 0.67
104 01101000 68 4.06 5.94 0.68
105 01101001 69 4.10 5.90 0.70
106 01101010 6A 4.14 5.86 0.71
107 01101011 6B 4.18 5.82 0.72
108 01101100 6C 4.22 5.78 0.73
109 01101101 6D 4.26 5.74 0.74
110 01101110 6E 4.30 5.70 0.75
111 01101111 6F 4.34 5.66 0.77
112 01110000 70 4.38 5.63 0.78
113 01110001 71 4.41 5.59 0.79
114 01110010 72 4.45 5.55 0.80
115 01110011 73 4.49 5.51 0.82
116 01110100 74 4.53 5.47 0.83
117 01110101 75 4.57 5.43 0.84
118 01110110 76 4.61 5.39 0.86
119 01110111 77 4.65 5.35 0.87
120 01111000 78 4.69 5.31 0.88
121 01111001 79 4.73 5.27 0.90
122 01111010 7A 4.77 5.23 0.91
123 01111011 7B 4.80 5.20 0.92
124 01111100 7C 4.84 5.16 0.94
125 01111101 7D 4.88 5.12 0.95
126 01111110 7E 4.92 5.08 0.97
127 01111111 7F 4.96 5.04 0.98
128 10000000 80 5.00 5.00 1.00
129 10000001 81 5.04 4.96 1.02
130 10000010 82 5.08 4.92 1.03
131 10000011 83 5.12 4.88 1.05
132 10000100 84 5.16 4.84 1.06
133 10000101 85 5.20 4.80 1.08
134 10000110 86 5.23 4.77 1.10
135 10000111 87 5.27 4.73 1.12
136 10001000 88 5.31 4.69 1.13
137 10001001 89 5.35 4.65 1.15
138 10001010 8A 5.39 4.61 1.17
139 10001011 8B 5.43 4.57 1.19
140 10001100 8C 5.47 4.53 1.21
141 10001101 8D 5.51 4.49 1.23
142 10001110 8E 5.55 4.45 1.25
143 10001111 8F 5.59 4.41 1.27
144 10010000 90 5.63 4.38 1.29
145 10010001 91 5.66 4.34 1.31
146 10010010 92 5.70 4.30 1.33
147 10010011 93 5.74 4.26 1.35
148 10010100 94 5.78 4.22 1.37
149 10010101 95 5.82 4.18 1.39
150 10010110 96 5.86 4.14 1.42
151 10010111 97 5.90 4.10 1.44
152 10011000 98 5.94 4.06 1.46
153 10011001 99 5.98 4.02 1.49
154 10011010 9A 6.02 3.98 1.51
155 10011011 9B 6.05 3.95 1.53
156 10011100 9C 6.09 3.91 1.56
157 10011101 9D 6.13 3.87 1.59
158 10011110 9E 6.17 3.83 1.61
159 10011111 9F 6.21 3.79 1.64
160 10100000 A0 6.25 3.75 1.67
161 10100001 A1 6.29 3.71 1.69
162 10100010 A2 6.33 3.67 1.72
163 10100011 A3 6.37 3.63 1.75
164 10100100 A4 6.41 3.59 1.78
165 10100101 A5 6.45 3.55 1.81
166 10100110 A6 6.48 3.52 1.84
167 10100111 A7 6.52 3.48 1.88
168 10101000 A8 6.56 3.44 1.91
169 10101001 A9 6.60 3.40 1.94
170 10101010 AA 6.64 3.36 1.98
171 10101011 AB 6.68 3.32 2.01
172 10101100 AC 6.72 3.28 2.05
173 10101101 AD 6.76 3.24 2.08
174 10101110 AE 6.80 3.20 2.12
175 10101111 AF 6.84 3.16 2.16
176 10110000 B0 6.88 3.13 2.20
177 10110001 B1 6.91 3.09 2.24
178 10110010 B2 6.95 3.05 2.28
179 10110011 B3 6.99 3.01 2.32
180 10110100 B4 7.03 2.97 2.37
181 10110101 B5 7.07 2.93 2.41
182 10110110 B6 7.11 2.89 2.46
183 10110111 B7 7.15 2.85 2.51
184 10111000 B8 7.19 2.81 2.56
185 10111001 B9 7.23 2.77 2.61
186 10111010 BA 7.27 2.73 2.66
187 10111011 BB 7.30 2.70 2.71
188 10111100 BC 7.34 2.66 2.76
189 10111101 BD 7.38 2.62 2.82
190 10111110 BE 7.42 2.58 2.88
191 10111111 BF 7.46 2.54 2.94
192 11000000 C0 7.50 2.50 3.00
193 11000001 C1 7.54 2.46 3.06
194 11000010 C2 7.58 2.42 3.13
195 11000011 C3 7.62 2.38 3.20
196 11000100 C4 7.66 2.34 3.27
197 11000101 C5 7.70 2.30 3.34
198 11000110 C6 7.73 2.27 3.41
199 11000111 C7 7.77 2.23 3.49
200 11001000 C8 7.81 2.19 3.57
201 11001001 C9 7.85 2.15 3.65
202 11001010 CA 7.89 2.11 3.74
203 11001011 CB 7.93 2.07 3.83
204 11001100 CC 7.97 2.03 3.92
205 11001101 CD 8.01 1.99 4.02
206 11001110 CE 8.05 1.95 4.12
207 11001111 CF 8.09 1.91 4.22
208 11010000 D0 8.13 1.88 4.33
209 11010001 D1 8.16 1.84 4.45
210 11010010 D2 8.20 1.80 4.57
211 11010011 D3 8.24 1.76 4.69
212 11010100 D4 8.28 1.72 4.82
213 11010101 D5 8.32 1.68 4.95
214 11010110 D6 8.36 1.64 5.10
215 11010111 D7 8.40 1.60 5.24
216 11011000 D8 8.44 1.56 5.40
217 11011001 D9 8.48 1.52 5.56
218 11011010 DA 8.52 1.48 5.74
219 11011011 DB 8.55 1.45 5.92
220 11011100 DC 8.59 1.41 6.11
221 11011101 DD 8.63 1.37 6.31
222 11011110 DE 8.67 1.33 6.53
223 11011111 DF 8.71 1.29 6.76
224 11100000 E0 8.75 1.25 7.00
225 11100001 E1 8.79 1.21 7.26
226 11100010 E2 8.83 1.17 7.53
227 11100011 E3 8.87 1.13 7.83
228 11100100 E4 8.91 1.09 8.14
229 11100101 E5 8.95 1.05 8.48
230 11100110 E6 8.98 1.02 8.85
231 11100111 E7 9.02 0.98 9.24
232 11101000 E8 9.06 0.94 9.67
233 11101001 E9 9.10 0.90 10.13
234 11101010 EA 9.14 0.86 10.64
235 11101011 EB 9.18 0.82 11.19
236 11101100 EC 9.22 0.78 11.80
237 11101101 ED 9.26 0.74 12.47
238 11101110 EE 9.30 0.70 13.22
239 11101111 EF 9.34 0.66 14.06
240 11110000 F0 9.38 0.63 15.00
241 11110001 F1 9.41 0.59 16.07
242 11110010 F2 9.45 0.55 17.29
243 11110011 F3 9.49 0.51 18.69
244 11110100 F4 9.53 0.47 20.33
245 11110101 F5 9.57 0.43 22.27
246 11110110 F6 9.61 0.39 24.60
247 11110111 F7 9.65 0.35 27.44
248 11111000 F8 9.69 0.31 31.00
249 11111001 F9 9.73 0.27 35.57
250 11111010 FA 9.77 0.23 41.67
251 11111011 FB 9.80 0.20 50.20
252 11111100 FC 9.84 0.16 63.00
253 11111101 FD 9.88 0.12 84.33
254 11111110 FE 9.92 0.08 127.00
255 11111111 FF 9.96 0.04 255.00

7.5 Programming

7.5.1 SPI Digital Interface

The TPL0202 uses a 3-wire SPI-compatible serial data interface. This write-only interface has three inputs: chip-select (CS), data clock (SCLK), and data input (DIN). Drive CS low to enable the serial interface and clock data synchronously into the shift register on each SCLK rising edge. The WRITE commands (C1, C0 = 00 or 01) require 16 clock cycles to clock in the command, address, and data. The COPY commands (C1, C0 = 10 or 11) can use either eight clock cycles to transfer only command and address bits or 16 clock cycles, with the device disregarding 8 data bits. After loading data into the shift register, drive CS high to latch the data into the appropriate potentiometer control register and disable the serial interface. Keep CS low during the entire serial data stream to avoid corruption of the data.

TPL0202 spwrite_LIS135.gif Figure 26. Digital Interface Write Sequence
TPL0202 timing_LIS135.gif Figure 27. Digital Interface Timing Diagram

7.6 Register Map

Table 2. Register Map

CLOCK EDGE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
– – C1 C0 – – A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
Write Wiper Register A 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 Wiper Register A and B 0 0 0 0 0 0 1 1 D7 D6 D5 D4 D3 D2 D1 D0
Write NV Register A 0 0 0 1 0 0 0 1 D7 D6 D5 D4 D3 D2 D1 D0
Write NV Register B 0 0 0 1 0 0 1 0 D7 D6 D5 D4 D3 D2 D1 D0
Write NV Register A and B 0 0 0 1 0 0 1 1 D7 D6 D5 D4 D3 D2 D1 D0
Copy Wiper Register A to NV Register A 0 0 1 0 0 0 0 1 – – – – – – – –
Copy Wiper Register B to NV Register B 0 0 1 0 0 0 1 0 – – – – – – – –
Copy Both Wiper Registers to NV Registers 0 0 1 0 0 0 1 1 – – – – – – – –
Copy NV Register A to Wiper Register A 0 0 1 1 0 0 0 1 – – – – – – – –
Copy NV Register B to Wiper Register A 0 0 1 1 0 0 1 0 – – – – – – – –
Copy Both NV Registers to Wiper Registers 0 0 1 1 0 0 1 1 – – – – – – – –

7.6.1 Digital Interface Format

The data format consists of three elements: command bits, address bits, and data bits. The command bits (C1 and C0) indicate the action to be taken such as changing or storing the wiper position. The address bits (A1 and A0) specify which potentiometer the command affects and the 8 data bits (D7 to D0) specify the wiper position.

7.6.2 Write-Wiper Register (Command 00)

Data written to the write-wiper registers (C1, C0 = 00) controls the wiper positions. The 8 data bits (D7 to D0) indicate the position of the wiper. If DIN = 0x00h, the wiper moves to the position closest to the L terminal. If DIN = 0xFFh, the wiper moves to the position closest to the H terminal. This command writes data to the volatile RAM, leaving the NV registers unchanged. When the device powers up, the data stored in the NV registers transfers to the volatile wiper register, moving the wiper to the stored position

7.6.3 Write-NV Register (Command 01)

This command (C1, C0 = 01) stores the position of the wipers to the NV registers for use at power-up. Alternatively, the copy wiper register to NV register command can be used to store the position of the wipers to the NV registers. Writing to the NV registers does not affect the position of the wipers.

7.6.4 Copy Wiper Register to NV Register (Command 10)

This command (C1, C0 = 10) stores the current position of the wiper to the NV register, for use at power-up. This command may affect one potentiometer at a time, or both simultaneously, depending on the state of A1 and A0. Alternatively, the write NV register command can be used to store the current position of the wiper to the NV register.

7.6.5 Copy NV Register to Wiper Register (Command 11)

This command (C1, C0 = 11) restores the wiper position to the previously stored position in the NV register. This command may affect one potentiometer at a time, or both simultaneously, depending on the state of A1 and A0.