X95840 ® Low Noise/Low Power/2-Wire Bus/256 Taps Data Sheet September 27, 2005 Quad Digital Controlled Potentiometers (XDCP™) The X95840 integrates four digitally controlled potentiometers (XDCP) on a monolithic CMOS integrated circuit. The digitally controlled potentiometers are implemented with a combination of resistor elements and CMOS switches. The position of the wipers are controlled by the user through the 2-wire bus interface. Each potentiometer has an associated volatile Wiper Register (WR) and a non-volatile Initial Value Register (IVR), that can be directly written to and read by the user. The contents of the WR controls the position of the wiper. At power up the device recalls the contents of the four DCP’s IVR to the corresponding WRs. The DCPs can be used as three-terminal potentiometers or as two-terminal variable resistors in a wide variety of applications including control, parameter adjustments, and signal processing. PART NUMBER X95840WV20I-2.7* X95840WV G RESISTANCE OPTION PACKAGE 10kΩ 20 Ld TSSOP X95840WV20IZ-2.7* X95840WV Z G (Note) 10kΩ 20 Ld TSSOP (Pb-free) X95840UV20I-2.7* 50kΩ X95840UV G X95840UV20IZ-2.7* X95840UV Z G (Note) • Four Potentiometers in One Package • 256 Resistor Taps-0.4% Resolution • 2-Wire Serial Interface • Wiper Resistance: 70Ω Typical @ 3.3V • Non-Volatile Storage of Wiper Position • Standby Current < 5µA Max • Power Supply: 2.7V to 5.5V • 50kΩ, 10kΩ Total Resistance • High Reliability - Endurance: 150,000 data changes per bit per register - Register data retention: 50 years @ T ≤ 75°C • 20 Ld TSSOP • Pb-Free Plus Anneal Available (RoHS Compliant) 50kΩ X95840 (20 LD TSSOP) TOP VIEW RH3 1 20 RW0 RL3 2 19 RL0 RW3 3 18 RH0 20 Ld TSSOP A2 4 17 WP 20 Ld TSSOP (Pb-free) SCL 5 16 VCC SDA 6 15 A1 GND 7 14 A0 RW2 8 13 RH1 RL2 9 12 RL1 RH2 10 11 RW1 *Add “T1” suffix for tape and reel. NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 Features Pinouts Ordering Information PART MARKING FN8213.1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. XDCP is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005. All Rights Reserved All other trademarks mentioned are the property of their respective owners. X95840 Block Diagram VCC 2-wire Interface SDA SCL Power-up, Interface, Control and Status Logic WR3 DCP3 RH3 RW3 RL3 WR2 DCP2 RH2 RW2 RL2 WR1 DCP1 RH1 RW1 RL1 WR0 DCP0 RH0 RW0 RL0 A2 A1 A0 Non-Volatile Registers WP GND Pin Descriptions TSSOP PIN SYMBOL 1 RH3 “High” terminal of DCP3 2 RL3 “Low” terminal of DCP3 3 RW3 “Wiper” terminal of DCP3 4 A2 5 SCL 2-wire interface clock 6 SDA Serial data I/O for the 2-wire interface 7 GND Device ground pin 8 RW2 “Wiper” terminal of DCP2 9 RL2 “Low” terminal of DCP2 10 RH2 “High” terminal of DCP2 11 RW1 “Wiper” terminal of DCP1 12 RL1 “Low” terminal of DCP1 13 RH1 “High” terminal of DCP1 14 A0 Device address for the 2-wire interface 15 A1 Device address for the 2-wire interface 16 VCC Power supply pin 17 WP Hardware write protection pin. Active low. Prevents any “Write” operation of the 2-wire interface. 18 RH0 “High” terminal of DCP0 19 RL0 “Low” terminal of DCP0 20 RW0 “Wiper” terminal of DCP0 2 DESCRIPTION Device address for the 2-wire interface FN8213.1 September 27, 2005 X95840 Absolute Maximum Ratings Recommended Operating Conditions Storage temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Voltage at any digital interface pin with respect to GND . . . . . . . . . . . . . . . . . . . . . . -0.3V to VCC+0.3 VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6V Voltage at any DCP pin with respect to GND. . . . . . . . -0.3V to VCC Lead temperature (soldering, 10s). . . . . . . . . . . . . . . . . . . . . . 300°C IW (10s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±6mA Temperature Range (Industrial) . . . . . . . . . . . . . . . . . . -40°C to 85°C VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.5V Power rating of each DCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5mW Wiper current of each DCP . . . . . . . . . . . . . . . . . . . . . . . . . . ±3.0mA CAUTION: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only; functional operation of the device (at these or any other conditions above those listed in the operational sections of this specification) is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Analog Specifications SYMBOL RTOTAL Over recommended operating conditions unless otherwise stated. PARAMETER RH to RL resistance TEST CONDITIONS W, U versions respectively RH to RL resistance tolerance RW CH/CL/CW ILkgDCP Wiper resistance MIN MAX 10, 50 -20 VCC = 3.3V @ 25°C Wiper current = VCC / RTOTAL 70 Potentiometer Capacitance (Note 15) Leakage on DCP pins (Note 15) TYP (Note 1) kΩ +20 % 200 Ω 10/10/25 Voltage at pin from GND to VCC 0.1 UNIT pF 1 µA -1 1 LSB (Note 2) -0.5 0.5 LSB (Note 2) LSB (Note 2) VOLTAGE DIVIDER MODE (0V @ RLi; VCC @ RHi; measured at RWi, unloaded; i = 0, 1, 2, or 3) INL (Note 6) Integral non-linearity DNL (Note 5) Differential non-linearity ZSerror (Note 3) Zero-scale error FSerror (Note 4) Full-scale error VMATCH (Note 7) DCP to DCP matching TCV (Note 8) Ratiometric Temperature Coefficient Monotonic over all tap positions U option 0 1 7 W option 0 0.5 2 U option -7 -1 0 W option -2 -1 0 Any two DCPs at same tap position, same voltage at all RH terminals, and same voltage at all RL terminals -2 DCP Register set to 80 hex 2 ±4 LSB (Note 2) LSB (Note 2) ppm/°C RESISTOR MODE (Measurements between RWi and RLi with RHi not connected, or between RWi and RHi with RLi not connected. i = 0, 1, 2 or 3) RINL (Note 12) Intregal non-linearity RDNL (Note 11) Differential non-linearity Roffset (Note 10) Offset DCP register set between 20 hex and FF hex. Monotonic over all tap positions 1 MI (Note 9) -0.5 0.5 MI (Note 9) U option 0 1 7 MI (Note 9) W option 0 0.5 2 MI (Note 9) -2 2 MI (Note 9) RMATCH (Note 13) DCP to DCP Matching Any two DCPs at the same tap position with the same terminal voltages. TCR (Note 14) Resistance Temperature Coefficient DCP register set between 20 hex and FF hex 3 -1 ±45 ppm/°C FN8213.1 September 27, 2005 X95840 Operating Specifications Over the recommended operating conditions unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN TYP (Note 1) MAX UNITS ICC1 VCC supply current (Volatile write/read) fSCL = 400kHz; SDA = Open; (for 2-Wire, Active, Read and Volatile Write States only) 1 mA ICC2 VCC supply current (nonvolatile write) fSCL = 400kHz; SDA = Open; (for 2-Wire, Active, Nonvolatile Write State only) 3 mA VCC current (standby) VCC = +5.5V, 2 Wire Interface in Standby State 5 µA VCC = +3.6V, 2 Wire Interface in Standby State 2 µA 10 µA 1 µs 2.6 V ISB ILkgDig tDCP (Note 15) Vpor Leakage current, at pins A0, A1, A2, SDA, SCL, and WP pins Voltage at pin from GND to VCC DCP wiper response time SCL falling edge of last bit of DCP Data Byte to wiper change Power-on recall voltage Minimum VCC at which memory recall occurs VccRamp VCC ramp rate tD (Note 15) Power up delay -10 1.8 0.2 VCC above Vpor, to DCP Initial Value Register recall completed, and 2-Wire Interface in standby state V/ms 3 ms EEPROM SPECS EEPROM Endurance EEPROM Retention Temperature ≤ 75°C 150,000 Cycles 50 Years SERIAL INTERFACE SPECS VIL WP, A2, A1, A0, SDA, and SCL input buffer LOW voltage -0.3 0.3*Vcc V VIH WP, A2, A1, A0, SDA, and SCL input buffer HIGH voltage 0.7*Vcc Vcc+0.3 V Hysteresis (Note 15) SDA and SCL input buffer hysteresis 0.05* Vcc VOL (Note 15) SDA output buffer LOW voltage, sinking 4 mA Cpin (Note 15) fSCL tIN (Note 15) 0.4 V WP, A2, A1, A0, SDA, and SCL pin capacitance 10 pF SCL frequency 400 kHz Pulse width suppression time Any pulse narrower than the max spec is suppressed. at SDA and SCL inputs 50 ns 900 ns tAA (Note 15) SCL falling edge to SDA output data valid 0 V SCL falling edge crossing 30% of VCC, until SDA exits the 30% to 70% of VCC window. Time the bus must be free before the start of a new transmission SDA crossing 70% of VCC during a STOP condition, to SDA crossing 70% of VCC during the following START condition. 1300 ns tLOW Clock LOW time Measured at the 30% of VCC crossing. 1300 ns tHIGH Clock HIGH time Measured at the 70% of VCC crossing. 600 ns tSU:STA START condition setup time SCL rising edge to SDA falling edge. Both crossing 70% of VCC. 600 ns tHD:STA START condition hold time From SDA falling edge crossing 30% of VCC to SCL falling edge crossing 70% of VCC. 600 ns tBUF (Note 15) 4 FN8213.1 September 27, 2005 X95840 Operating Specifications Over the recommended operating conditions unless otherwise specified. (Continued) SYMBOL PARAMETER TYP (Note 1) TEST CONDITIONS MIN MAX UNITS 100 ns tSU:DAT Input data setup time From SDA exiting the 30% to 70% of VCC window, to SCL rising edge crossing 30% of VCC tHD:DAT Input data hold time From SCL rising edge crossing 70% of VCC to SDA entering the 30% to 70% of VCC window. 0 ns tSU:STO STOP condition setup time From SCL rising edge crossing 70% of VCC, to SDA rising edge crossing 30% of VCC. 600 ns tHD:STO STOP condition setup time From SDA rising edge to SCL falling edge. Both crossing 70% of VCC. 600 ns 0 ns tDH (Note 15) Output data hold time From SCL falling edge crossing 30% of VCC, until SDA enters the 30% to 70% of VCC window. tR (Note 15) SDA and SCL rise time From 30% to 70% of VCC 20 + 0.1 * Cb 250 ns tF (Note 15) SDA and SCL fall time From 70% to 30% of VCC 20 + 0.1 * Cb 250 ns Cb (Note 15) Capacitive loading of SDA or Total on-chip and off-chip SCL 10 400 pF Rpu (Note 15) SDA and SCL bus pull-up resistor off-chip 1 Maximum is determined by tR and tF. For Cb = 400pF, max is about 2~2.5kΩ. For Cb = 40pF, max is about 15~20kΩ tWP Non-volatile Write cycle time (Notes 15, 16) kΩ 12 20 ms tSU:WPA A2, A1, A0, and WP setup time Before START condition 600 ns tHD:WPA A2, A1, A0, and WP hold time After STOP condition 600 ns SDA vs SCL Timing tF SCL tHIGH tLOW tR tSU:DAT tSU:STA tHD:STA SDA (Input Timing) tHD:DAT tSU:STO tAA tDH tBUF SDA (Output Timing) 5 FN8213.1 September 27, 2005 X95840 WP, A0, A1, and A2 Pin Timing STOP START SCL Clk 1 SDA IN tSU:WPA tHD:WPA WP, A0, A1, or A2 NOTES: 1. Typical values are for TA = 25°C and 3.3V supply voltage. 2. LSB: [V(RW)255 - V(RW)0] / 255. V(RW)255 and V(RW)0 are V(RW) for the DCP register set to FF hex and 00 hex respectively. LSB is the incremental voltage when changing from one tap to an adjacent tap. 3. ZS error = V(RW)0 / LSB. 4. FS error = [V(RW)255 - VCC] / LSB. 5. DNL = [V(RW)i - V(RW)i-1] / LSB-1, for i = 1 to 255. i is the DCP register setting. 6. INL = [V(RW)i – (i • LSB – V(RW)0)]/LSB for i = 1 to 255. 7. VMATCH = [V(RWx)i - V(RWy)i] / LSB, for i = 0 to 255, x = 0 to 3 and y = 0 to 3. Max ( V ( RW ) i ) – Min ( V ( RW ) i ) 10 6 - × ----------------8. TC V = --------------------------------------------------------------------------------------------[ Max ( V ( RW ) i ) + Min ( V ( RW ) i ) ] ⁄ 2 125°C for i = 16 to 240 decimal, T = -40°C to 85°C. Max( ) is the maximum value of the wiper voltage and Min ( ) is the minimum value of the wiper voltage over the temperature range. 9. MI = |R255 - R0| / 255. R255 and R0 are the measured resistances for the DCP register set to FF hex and 00 hex respectively. 10. Roffset = R0 / MI, when measuring between RW and RL. Roffset = R255 / MI, when measuring between RW and RH. 11. RDNL = (Ri - Ri-1) / MI, for i = 32 to 255. 12. RINL = [Ri - (MI • i) - R0] / MI, for i = 32 to 255. 13. RMATCH = (Ri,x - Ri,y) / MI, for i = 0 to 255, x = 0 to 3 and y = 0 to 3. 6 [ Max ( Ri ) – Min ( Ri ) ] 10 14. TC R = ---------------------------------------------------------------- × ----------------[ Max ( Ri ) + Min ( Ri ) ] ⁄ 2 125°C for i = 32 to 255, T = -40°C to 85°C. Max( ) is the maximum value of the resistance and Min ( ) is the minimum value of the resistance over the temperature range. 15. This parameter is not 100% tested. 16. tWC is the minimum cycle time to be allowed for any non-volatile Write by the user, unless Acknowledge Polling is used. It is the time from a valid STOP condition at the end of a Write sequence of a 2-wire serial interface Write operation, to the end of the self-timed internal non-volatile write cycle. 6 FN8213.1 September 27, 2005 X95840 Typical Performance Curves 1.8 160 Vcc = 2.7, T = 85°C Vcc = 2.7, T = -40°C 1.6 Vcc = 2.7, T = 25°C 1.4 120 1.2 STANDBY ICC (µA) WIPER RESISTANCE (Ω) 140 100 80 60 40 Vcc = 5.5, T = -40°C 20 0.8 50 0.4 Vcc = 5.5, T = 85°C Vcc = 5.5, T = 25°C 100 150 200 85°C 0.6 0.2 25°C 0.0 2.7 0 0 -40°C 1.0 250 3.2 3.7 0.15 0.3 Vcc = 5.5, T = -40°C 4.7 5.2 FIGURE 2. STANDBY ICC vs VCC FIGURE 1. WIPER RESISTANCE vs TAP POSITION [ I(RW) = VCC/RTOTAL ] FOR 50kΩ (U) 0.2 4.2 VCC (V) TAP POSITION (DECIMAL) Vcc = 2.7, T = -40°C Vcc = 5.5, T = -40°C Vcc = 2.7, T = -40°C Vcc = 2.7, T = 25°C Vcc = 5.5, T = 85°C 0.2 0.1 0.05 INL (LSB) DNL (LSB) 0.1 0 -0.05 0 Vcc = 2.7, T = 25°C Vcc = 2.7, T = 85°C -0.1 -0.1 -0.15 -0.2 0 Vcc = 5.5, T = 25°C Vcc = 2.7, T = 85°C Vcc = 5.5, T = 85°C -0.2 -0.3 50 100 150 200 Vcc = 5.5, T = 25°C 250 0 50 100 150 200 250 TAP POSITION (DECIMAL) TAP POSITION (DECIMAL) FIGURE 3. DNL vs TAP POSITION IN VOLTAGE DIVIDER MODE FOR 10kΩ (W) FIGURE 4. INL vs TAP POSITION IN VOLTAGE DIVIDER MODE FOR 10kΩ (W) 0 0.4 -0.1 -0.2 0.35 Vcc = 5.5V FSerror (LSB) ZSerror (LSB) -0.3 0.3 2.7V 0.25 -0.4 Vcc = 2.7V -0.5 -0.6 -0.7 0.2 -0.8 5.5V -0.9 0.15 -40 -20 0 20 40 60 TEMPERATURE (°C) FIGURE 5. ZSerror vs TEMPERATURE 7 80 -1 -40 -20 0 20 40 60 80 TEMPERATURE (°C) FIGURE 6. FSerror vs TEMPERATURE FN8213.1 September 27, 2005 X95840 Typical Performance Curves (Continued) 0.3 0.5 Vcc = 2.7, T = 25°C 0.4 Vcc = 5.5, T = 25°C 0.2 INL (LSB) DNL (LSB) Vcc = 5.5, T = -40°C 0.2 0.1 0 -0.1 0.1 Vcc = 5.5, T = 85°C 0 -0.1 -0.2 Vcc = 5.5, T = 85°C -0.3 Vcc = 2.7, T = 85°C Vcc = 2.7, T = -40°C Vcc = 5.5, T = -40°C -0.2 -0.3 32 82 132 182 TAP POSITION (DECIMAL) -0.4 Vcc = 2.7, T = 85°C Vcc = 5.5, T = 25°C -0.5 32 82 132 232 Vcc = 2.7, T = -40°C 182 232 TAP POSITION (DECIMAL) FIGURE 7. DNL vs TAP POSITION IN Rheostat MODE FOR 50kΩ (U) FIGURE 8. INL vs TAP POSITION IN Rheostat MODE FOR 50kΩ (U) 20 1.50 1.00 10 0.50 0.00 2.7V TC (ppm/°C) END TO END RTOTAL CHANGE (%) Vcc = 2.7, T = 25°C 0.3 5.5V -0.50 0 -10 -1.00 -1.50 -40 -20 0 20 40 60 80 TEMPERATURE (°C) -20 32 82 132 182 232 TAP POSITION (DECIMAL) FIGURE 10. TC FOR VOLTAGE DIVIDER MODE IN ppm FIGURE 9. END TO END RTOTAL % CHANGE vs TEMPERATURE 35 INPUT 25 TC (ppm/°C) 15 5 OUTPUT -5 Tap Position = Mid Point RTOTAL = 9.4K -15 -25 32 57 82 107 132 157 182 207 TAP POSITION (DECIMAL) 232 FIGURE 12. FREQUENCY RESPONSE (2.2MHz) FIGURE 11. TC FOR Rheostat MODE IN ppm 8 FN8213.1 September 27, 2005 X95840 Typical Performance Curves (Continued) SCL Signal at Wiper (Wiper Unloaded) Signal at Wiper (Wiper Unloaded Movement From ffh to 00h) Wiper Movement Mid Point From 80h to 7fh FIGURE 13. MIDSCALE GLITCH, CODE 80h TO 7Fh (WIPER 0) FIGURE 14. LARGE SIGNAL SETTLING TIME Principles of Operation Memory Description The X95840 in as integrated circuit incorporating four DCPs with their associated registers, non-volatile memory, and a 2wire serial interface providing direct communication between a host and the potentiometers and memory. The X95840 contains eight non-volatile bytes. they are accessed by 2-wire interface operations with Address Bytes 0 through 7 decimal. The first four non-volatile bytes at addresses 0, 1, 2, and 3, contain the initial value loaded at power-up into the volatile Wiper Registers (WRs) of DCP0, DCP1, DCP2, and DCP3 respectively. Bytes at addresses 4, 5, and 6 are available to the user as general purpose registers. The byte at address 7 is reserved; the user should not write to it, and its value should be ignored if read. DCP Description Each DCP is implemented with a combination of resistor elements and CMOS switches. The physical ends of each DCP are equivalent to the fixed terminals of a mechanical potentiometer (RH and RL pins). The RW pin of each DCP is connected to intermediate nodes, and is equivalent to the wiper terminal of a mechanical potentiometer. The position of the wiper terminal within the DCP is controlled by an 8-bit volatile Wiper Register (WR). Each DCP has its own WR. When the WR of a DCP contains all zeroes (WR<7:0>: 00h), its wiper terminal (RW) is closest to its “Low” terminal (RL). When the WR of a DCP contains all ones (WR<7:0>: FFh), its wiper terminal (RW) is closest to its “High” terminal (RH). As the value of the WR increases from all zeroes (00h) to all ones (255 decimal), the wiper moves monotonically from the position closest to RL to the closest to RH. At the same time, the resistance between RW and RL increases monotonically, while the resistance between RH and RW decreases monotonically. While the X95840 is being powered up, all four WRs are reset to 80h (128 decimal), which locates RW roughly at the center between RL and RH. Soon after the power supply voltage becomes large enough for reliable non-volatile memory reading, the X95840 reads the value stored on four different non-volatile Initial Value Registers (IVRs) and loads them into their corresponding WRs. The volatile WR, and the non-volatile Initial Value Register (IVR) of a DCP are accessed with the same Address Byte. A volatile byte at address 8 decimal, controls what byte is read or written when accessing DCP registers: the WR, the IVR, or both. When the byte at address 8 is all zeroes, which is the default at power up: • A read operation to addresses 0, 1, 2 or 3 outputs the value of the non-volatile IVRs. • A write operation to addresses 0, 1, 2, or 3 writes the same value to the WR and IVR of the corresponding DCP. When the byte at address 8 is 80h (128 decimal): • A read operation to addresses 0, 1, 2, or 3 outputs the value of the volatile WR. • A write operation to addresses 0, 1, 2, or 3 only writes to the corresponding volatile WR. It is not possible to write to an IVR without writing the same value to its corresponding WR. The WRs and IVRs can be read or written directly using the 2-wire serial interface as described in the following sections. 00h and 80h are the only values that should be written to address 8. All other values are reserved and must not be written to address 8. To access the general purpose bytes at addresses 4, 5, or 6, the value at address 8 must be all zeros. 9 FN8213.1 September 27, 2005 X95840 Figure 15). A START condition is ignored during the power up sequence and during internal non-volatile write cycles. The X95840 is pre-programed with 80h in the four IVRs. TABLE 1. MEMORY MAP ADDRESS NON-VOLATILE VOLATILE 8 — Access Control 7 All 2-wire interface operations must be terminated by a STOP condition, which is a LOW to HIGH transition of SDA while SCL is HIGH (See Figure 15). A STOP condition at the end of a read operation, or at the end of a write operation to volatile bytes only places the device in its standby mode. A STOP condition during a write operation to a non-volatile byte, initiates an internal non-volatile write cycle. The device enters its standby state when the internal non-volatile write cycle is completed. Reserved 6 5 4 General Purpose Not Available 3 2 1 0 IVR3 IVR2 IVR1 IVR0 WR3 WR2 WR1 WR0 WR: Wiper Register, IVR: Initial value Register. 2-Wire Serial Interface The X95840 supports a bidirectional bus oriented protocol. The protocol defines any device that sends data onto the bus as a transmitter and the receiving device as the receiver. The device controlling the transfer is a master and the device being controlled is the slave. The master always initiates data transfers and provides the clock for both transmit and receive operations. Therefore, the X95840 operates as a slave device in all applications. All communication over the 2-wire interface is conducted by sending the MSB of each byte of data first. Protocol Conventions Data states on the SDA line can change only during SCL LOW periods. SDA state changes during SCL HIGH are reserved for indicating START and STOP conditions (See Figure 15). On power up of the X95840 the SDA pin is in the input mode. All 2-wire interface operations must begin with a START condition, which is a HIGH to LOW transition of SDA while SCL is HIGH. The X95840 continuously monitors the SDA and SCL lines for the START condition and does not respond to any command until this condition is met (See An ACK, Acknowledge, is a software convention used to indicate a successful data transfer. The transmitting device, either master or slave, releases the SDA bus after transmitting eight bits. During the ninth clock cycle, the receiver pulls the SDA line LOW to acknowledge the reception of the eight bits of data (See Figure 16). The X95840 responds with an ACK after recognition of a START condition followed by a valid Identification Byte, and once again after successful receipt of an Address Byte. The X95840 also responds with an ACK after receiving a Data Byte of a write operation. The master must respond with an ACK after receiving a Data Byte of a read operation A valid Identification Byte contains 1010 as the four MSBs, and the following three bits matching the logic values present at pins A2, A1, and A0. The LSB in the Read/Write bit. Its value is “1” for a Read operation, and “0” for a Write operation. See Table 2. TABLE 2. IDENTIFICATION BYTE FORMAT Logic values at pins A2, A1, and A0 respectively 1 0 1 0 (MSB) A2 A1 A0 R/W (LSB) SCL SDA START DATA STABLE DATA CHANGE DATA STABLE STOP FIGURE 15. VALID DATA CHANGES, START, AND STOP CONDITIONS 10 FN8213.1 September 27, 2005 X95840 SCL from Master 1 8 9 SDA Output from Transmitter High Impedance High Impedance SDA Output from Receiver START ACK FIGURE 16. ACKNOWLEDGE RESPONSE FROM RECEIVER Write Signals from the Master Signal at SDA S t a r t 1 0 1 0 A2A1A00 Signals from the X95840 S t o p Data Byte Address Byte Identification Byte 0 0 0 0 A C K A C K A C K FIGURE 17. BYTE WRITE SEQUENCE Write Operation A Write operation requires a START condition, followed by a valid Identification Byte, a valid Address Byte, a Data Byte, and a STOP condition. After each of the three bytes, the X95840 responds with an ACK. At this time, if the Data Byte is to be written only to volatile registers, then the device enters its standby state. If the Data Byte is to be written also to non-volatile memory, the X95840 begins its internal write cycle to non-volatile memory. During the internal non-volatile write cycle, the device ignores transitions at the SDA and SCL pins, and the SDA output is at a high impedance state. When the internal non-volatile write cycle is completed, the X95840 enters its standby state (See Figure 17). The byte at address 00001000 bin (8 decimal) determines if the Data Byte is to be written to volatile and/or non-volatile memory. See “Memory Description” on page 9. Data Protection The WP pin has to be at logic HIGH to perform any Write operation to the device. When the WP is active (LOW) the device ignores Data Bytes of a Write Operation, does not respond to the Data Bytes with an ACK, and instead, goes to its standby state waiting for a new START condition. 11 A STOP condition also acts as a protection of non-volatile memory. A valid Identification Byte, Address Byte, and total number of SCL pulses act as a protection of both volatile and non-volatile registers. During a Write sequence, the Data Byte is loaded into an internal shift register as it is received. If the Address Byte is 0, 1, 2, 3, or 8 decimal, the Data Byte is transferred to the appropriate Wiper Register (WR) or to the Access Control Register, at the falling edge of the SCL pulse that loads the last bit (LSB) of the Data Byte. If the Address Byte is between 0 and 6 (inclusive), and the Access Control Register is all zeros (default), then the STOP condition initiates the internal write cycle to non-volatile memory. Read Operation A Read operation consist of a three byte instruction followed by one or more Data Bytes (See Figure 18). The master initiates the operation issuing the following sequence: a START, the Identification byte with the R/W bit set to “0”, an Address Byte, a second START, and a second Identification byte with the R/W bit set to “1”. After each of the three bytes, the X95840 responds with an ACK. Then the X95840 transmits Data Bytes as long as the master responds with an ACK during the SCL cycle following the eight bit of each byte. The master terminates the read operation (issuing a FN8213.1 September 27, 2005 X95840 STOP condition) following the last bit of the last Data Byte (See Figure 18). pointer “rolls over” to 00h, and the device continues to output data for each ACK received. The Data Bytes are from the memory location indicated by an internal pointer. This pointer initial value is determined by the Address Byte in the Read operation instruction, and increments by one during transmission of each Data Byte. After reaching the memory location 01Fh (8 decimal) the The byte at address 00001000 bin (8 decimal) determines if the Data Bytes being read are from volatile or non-volatile memory. See “Memory Description” on page 9. Signals from the Master S t a r t Identification Byte with R/W=0 S t a r t Address Byte Identification Byte with R/W=1 A C K S t o p A C K Signal at SDA 10 10 10 10 0 A C K Signals from the Slave A C K 1 A C K First Read Data Byte Last Read Data Byte FIGURE 18. READ SEQUENCE 12 FN8213.1 September 27, 2005 X95840 TSSOP Packaging Information 20-Lead Plastic, TSSOP, Package Code V20 .025 (.65) BSC .010 (.25) Gage Plane .169 (4.3) .252 (6.4) BSC .177 (4.5) 0° - 8° Seating Plane .019 (.50) .029 (.75) Detail A (20X) .031 (.80) .041 (1.05) .252 (6.4) .260 (6.6) .041 (1.05) .0075 (.19) .0118 (.30) See Detail “A” .002 (.05) .006 (.15) NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 13 FN8213.1 September 27, 2005