Copyright 1995 by Dallas Semiconductor Corporation.All Rights Reserved. For important information regardingpatents and other intellectual property rights, please refer toDallas Semiconductor data books.

DS1804NV Trimmer Potentiometer

DS1804

PRODUCT PREVIEW

071295 1/6

FEATURES Single 100Position Linear Taper Potentiometer

Nonvolatile OnDemand Wiper Storage

Operates from 3V or 5V supplies

Up/Down, Increment Controlled Interface

Resistance Values: 10K, 50K, and 100K

Available in 8Pin (300 Mil) DIP, 8Pin (150 Mil) SOICpackages

Operating Temperature: Commercial: 0C to 70C Industrial: 40C to 85C

PIN ASSIGNMENT

VCCCSL

W

1

2

3

4

INCU/D

H

GND

8

7

6

5

8PIN DIP (300 MIL)8PIN SOIC (150 MIL)

PIN DESCRIPTIONH HighEnd of ResistorL LowEnd of Resistor W Wiper TerminalVCC 3V or 5V Power Supply InputCS Chip SelectU/D Up/Down Control InputINC Increment/Decrement

Counter InputGND Ground

DESCRIPTIONThe DS1804 is a nonvolatile digital potentiometer hav-ing 100 positions. The device provides an ideal methodfor lowcost trimming applications using a CPU ormanual control input with minimal external circuitry.Wiper position of the DS1804 can be stored in EEPROMmemory on demand. The devices wiper position ismanipulated by a 3terminal port that provides an incre-ment/decrement counter controlled interface. This portconsist of the control inputs CS, INC, and U/D.

The DS1804 is available in three resistor grades whichinclude a 10K, 50K, and 100K. Commercial andindustrial versions of the device are available. Addition-ally, the DS1804 will operate from 3V or 5V supplies andis ideal for portable application requirements. Twopackaging options are available and include the 8pin(300 mil) DIP and 8Pin (150 mil) SOIC.

DS1804

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OPERATIONThe DS1804 is a single nonvolatile potentiometer. Thedevice has a total of 100 tappoints including the L andH terminals. A total of 99 resistive segments existbetween the L and H terminals. These tappoints areaccessible to the Wterminal whose position is con-trolled via a 3terminal control port. A block diagram ofthe DS1804 is shown in Figure 1.

The 3terminal port of the DS1804 provides an incre-ment/decrement interface which is activated via a chipselect input. This interface consists of the input signalsCS, INC, and U/D. These input signals control a 7bitup/down counter. The output of the 7bit up/downcounter controls a 1 of 100 decoder to select wiper posi-tion. Additionally, this interface provides for a wiper stor-age operation using the CS and INC input control pins.The timing diagram for the 3terminal interface controlis shown in Figure 2.

PIN DESCRIPTIONSVCC Power Supply Terminal. The DS1804 will sup-port supply voltages ranging from +2.7 to +5.5 volts.

GND Ground Terminal.

H Highend of Resistor. This is the highend terminalof the potentiometer. It is not required that this terminalbe connected to a potential greater than the Lterminal.Voltage applied to the Hterminal can not exceed thepowersupply voltage, VCC, or go below ground.

L Lowend of Resistor This is the lowend terminalof the potentiometer. It is not required that this terminalbe connected to a potential less than the Hterminal.Voltage applied to the Lterminal cannot exceed thepowersupply voltage, VCC, or go below ground.

W Wiper of the Potentiometer. This pin is the wiperterminal of the potentiometer. Its position on the resistorarray is controlled by the 3terminal control port. Volt-age applied to the Wterminal cannot exceed the pow-ersupply voltage, VCC, or go below ground.

CS Chip Select. The CS input is used to activate thecontrol port of the DS1804. This input is active low.When in a highstate, activity on the INC and U/D portpins will not affect or change wiper position.

INC Wiper Movement Control. This input provides forwiper position changes when the CS pin is low. Wiperposition changes of the Wterminal will occur one posi-tion per hightolow transition of this input signal. Posi-tion changes will not occur if the CS pin is in a highstate.

U/D Up/Down Control. This input sets the direction ofwiper movement. When in a highstate and CS is low,any hightolow transition on INC will cause a oneposition movement of the wiper towards the Hterminal. When in a lowstate and CS is low, any hightolowtransitions on INC will cause the position of the wiper tomove towards the Lterminal.

DS1804 BLOCK DIAGRAM Figure 1

3-TERMINAL

GND

CONTROL LOGIC

NV MEMORY

100-

TO-1

MUL

TIPL

EXER POS 99

POS 0

H

L

W

CSINCU/D

VCC

UNIT

CONTROL PORT

DS1804

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POWERUP/POWERDOWN CONDITIONSOn powerup the DS1804 will load the value ofEEPROM memory into the wiper position register (or 1of 100 decoder). The value of this register can then beset to another wiper position if desired, by using the3terminal control port. On powerup, wiper positionwill be loaded within a maximum time period of 500 sonce the powersupply is stable. Additionally, the 3terminal interface port will be active after 50 ms.

On powerdown, the wiper position register data will belost. On the next device powerup, the value ofEEPROM memory will be loaded into the wiper positionregister.

On shipment from the factory, Dallas Semiconductordoes not guarantee a specified EEPROM memoryvalue. This value should be set by the customer asneeded. The next section discusses wiper storageoperation for the DS1804.

NONVOLATILE WIPER STORAGEWiper position of the DS1804 can be stored using theINC and CS inputs. Storage of the wiper position takesplace, whenever the CS input transitions from lowto

high while the INC is high. Once this condition hasoccurred the value of the current wiper position will bewritten to EEPROM memory.

The DS1804 is specified to accept 50,000 writes toEEPROM before a wearout condition. After wearoutthe DS1804 will still function and wiper position can bechanged during powered conditions using the 3termi-nal control port. However, on powerup the wiperposi-tion will be indeterminate.

ONE TIME PROGRAMMABILITY (OTP)The DS1804 can be easily used as an OTP device. Theuser of the DS1804 can trim the desired value of thewiper position and set this position for storage asdescribed above. Any activity through the 3terminalport can then be prevented by connecting the CS inputpin to VCC. Also, an OTP application does notadversely affect the number of times EEPROM is writ-ten, since EEPROM will only be loaded and not writtenduring a powerup or powerdown condition.

On powerup the DS1804 will load the current value ofEEPROM memory into the wiper position register.

DS1804

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ABSOLUTE MAXIMUM RATINGS*Voltage on Any Pin Relative to Ground 1.0V to +7.0VOperating Temperature 0C to 70C; commercial

40C to +85C; industrialStorage Temperature 55C to +125CSoldering Temperature 260C for 10 seconds

* This is a stress rating only and functional operation of the device at these or any other conditions abovethose indicated in the operation sections of this specification is not implied. Exposure to absolute maxi-mum rating conditions for extended periods of time may affect reliability.

RECOMMENDED DC OPERATING CONDITIONS (40C to +85C)PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Supply Voltage VCC +2.7 5.5 V 1

Input Logic 1 VIH 2.0 VCC+0.5 V 1, 2

Input Logic 0 VIL 0.5 +0.8+0.6

V 1, 15

Resistor Inputs L, H, W GND0.5 VCC+0.5 V 1, 3

DC ELECTRICAL CHARACTERISTICS (40C to +85C; VCC=2.7V to 5.5V)PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Supply Current ICC 400 A 4

Input Leakage ILI 1 +1 A

Wiper Resistance RW 400 1000

Wiper Current IW 1 mA

Standby Current3 Volts5 Volts

ISTBY1020 40

AA

5

Wiper Load Time tWLT 500 s 6

PowerUp Time tPU 50 ms 14

ANALOG RESISTOR CHARACTERISTICS (40C to +85C; VCC=2.7V to 5.5V)PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Total Resistance 1050100

K 7

EndtoEnd Resistor Tolerance 20 +20 % 8

Absolute Linearity 0.6 LSB 9

Relative Linearity 0.25 LSB 10

3 dB Cutoff Frequency fcutoff MHz 11

Temperature Coefficient 650 ppm/C

DS1804

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CAPACITANCE (25C; VCC=2.7V to 5.5V)PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Input Capacitance CIN 5 pF 12

Output Capacitance COUT 7 pF 12

AC ELECTRICAL CHARACTERISTICS (40C to +85C; VCC=2.7V to 5.5V)PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

CS to INC Setup tCI 50 ns 13

U/D to INC Setup tDI 100 ns 13

INC Low Period tIL 50 ns 13

INC High Period tIH 100 ns 13

INC Inactive to CS Inactive tIC 500 ns 13

CS Deselect Time tCPH 100 ns 13

Wiper Change to INC Low tIW 200 ns 13

INC Rise and Fall Times tR, tF 500 s 13

INC Low to CS Inactive tIK 50 ns 16

Wiper Storage Time tWST 10 ms 13, 17

NOTES:1. All voltages are referenced to ground.

2. Valid for VCC = 5V only.

3. Resistor input voltages cannot go below ground or exceed VCC by the amounts as shown in the table.

4. Maximum current specifications are based on the clock rate of INC input. This specification represents thecurrent required when changing the wiper position.

5. Standby current levels apply when all inputs are driven to appropriate supply levels. CS, INC, U/D = VCC.

6. Wiper load time is specified as the time required for the DS1804 to load the wiper position with the contents ofnonvolatile memory once VCC has reached a stable operating voltage equal to or greater than 2.7V.

7. The DS1804 is available in three resistor values. These include the DS1804010; 10K , the DS180405050K; and the DS1804100 100K.

8. The endtoend resistance tolerance of the DS1804 can be expected to shift with temperature. However, thischange will not exceed 20% of the nominal resistor value of the part.

9. Absolute linearity is used to compare measured wiper voltage versus expected wiper voltage as determinedby wiper position. The DS1804 is specified to provide an absolute linearity of 0.60 LSB

10. Relative linearity is used to determined the change in voltage between successive tap positions. The DS1804is specified to provide a relative linearity specification of 0.25 LSB.

11. 3 dB cutoff frequency characteristics for the DS1804 depend on potentiometer total resistance.DS1804010, 1 MHz, DS1804050; 200 KHz, and DS1804100; 100 KHz.

DS1804

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12. Capacitance values apply at 25C.

13. See Figure 2.

14. Powerup time is specified as the time required before the 3terminal control becomes active after a stablepower supply level has been reached.

15. At VCC = 2.7V, VIL = 0.8V

16. The INC low to CS inactive is specified to be 50 ns minimum. This is the transition condition which allows the DS1804 3terminal port to become inactive without writing the EEPROM memory of the part.

17. Wiper Storage Time, tWST, is the time require for the DS1804 to write EEPROM memory for storage of a newwiper position. The maximum time required to accomplish this task is specified at 10 ms.

3TERMINAL INTERFACE TIMING DIAGRAM Figure 2

tCI

tIW

tIKtF

tRtDI

tIL

tIHtIC tWPS

tCPH

WIPER STORAGE WIPER NONSTORAGECONDITION CONDITION

CS

INC

U/D

VW