INTEGRATED CIRCUITS SA5777A Dual air–core gauge driver Product specification Supersedes data of 1997 Feb 24 1999 Sep 20 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A DESCRIPTION PIN CONFIGURATION The SA5777A is a monolithic driver for controlling air-core (or differential) meters typically used in automotive instrument cluster applications. The circuit interfaces with a microprocessor through a serial bus and directly drives the air-core meter. The SA5777A has 10-bit resolution (0.35 degree) and is guaranteed to be monotonic. Data can be shifted through the part, allowing several SA5777As to be cascaded with only one chip-select line. On-chip current shut down logic protects the circuit from external faults. N Package FEATURES • 10-Bit resolution (0.35 degrees) • Exceptional accuracy (0.5 degrees, typical) • High-torque capability • Active differential drivers eliminate back-EMF issues • No RFI/EMI generation issues • Simple serial interface • Simple cascading capability for multiple meters • Internal fault protection • Only one external component required (bypass capacitor) C1– 1 16 C2+ C1+ 2 15 C2- AGND 3 14 COM VBB 4 13 AGND DATAOUT 5 12 DGND DATAIN 6 11 ST VCC 7 10 CS OE 8 9 SCLK D Package APPLICATION • Instrumentation utilizing air-core meters C1– 1 28 C2+ C1+ 2 27 C2- NC 3 26 NC NC 4 25 NC NC 5 24 COM AGND 6 23 AGND VBB 7 22 NC DATAOUT 8 21 NC DATAIN 9 20 DGND NC 10 19 ST NC 11 18 NC NC 12 17 NC VCC 13 16 CS OE 14 15 SCLK SL00460 Figure 1. Pin configuration ORDERING INFORMATION DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG # 16-Pin Plastic Dual In-Line Package (DIP) -40 to +85°C SA5777AN SOT38-4 28-Pin Plastic Small Outline Package (SO) -40 to +85°C SA5777AD SOT136-1 1999 Sep 20 2 853-1930 022368 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A BLOCK DIAGRAM VBB VBB OE C2+ 7 + – BIT DAC MUX C2– VBB/2 COM 8 7 + – BIT DAC MUX C1+ 8 C1– CS 9-BIT LATCH 9-BIT LATCH 10-BIT SHIFT REGISTER 10-BIT SHIFT REGISTER FAULT DETECTION ST VCC DIN SCLK DOUT SL00461 Figure 2. Block diagram Table 1. SA5777A Pin Descriptions for the N Package (Dual In-Line) Pin # Name 1. C1– Negative output connection to the TAN coil of meter #1. 2. C1+ Positive output connection to the TAN coil of meter #1. 3. AGND 4. VBB 5. DATAOUT Serial data output. Output of the internal shift register. When a new data word is shifted in, the old word is shifted out the DATAOUT pin. DATAOUT output is always active. 6. DATAIN Serial data input. A new data word is serially shifted into the part on the rising edge of SCLK. The data is shifted in MSB first, gauge 1 first. 7. VCC 5 V logic supply. The internal latches and registers are set to zero on the rising edge of this signal. 8. OE Output drivers are turned off when this input is low. 9. SCLK Serial clock input. Data is loaded into the part on the rising edge of SCLK. Data is shifted out of DATAOUT on the falling edge of SCLK. CS Active high chip select input. When CS is high, the part is enabled to receive a new serial input word. The high-to-low transition of CS loads the new 20-bit word into the DAC registers and updates the output. ST Status output. This is an open drain output and goes low when the coil output buffers (C1+, C1–, C2+, C2–, COM) have been disabled. The coil outputs may be disabled due to shorted outputs, over-temperature conditions, power-on reset, or by the output enable (OE) pin. Multiple status outputs , ST, may be wire OR’ed together. 10. 11. Function Ground for VBB supply. Pins 3, 12 and 13 should be connected on the circuit board. Analog supply. Nominally 13.5 V. 12. DGND Ground for VCC supply. Connect to Pins 3 and 13. 13. AGND Ground for VBB supply. Connect to Pins 3 and 12. 14. COM Output drive for biased coils. This output will be 1/2 of VBB. 15. C2– Negative output connection to the TAN coil of meter #2. 16. C2+ Positive output connection to the TAN coil of meter #2. 1999 Sep 20 3 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A Table 2. SA5777A Pin Descriptions for the D Package (Small Outline) Pin # Name 1. C1– Negative output connection to the TAN coil of meter #1. 2. C1+ Positive output connection to the TAN coil of meter #1. 3. NC No connect 4. NC No connect 5. NC No connect 6. AGND 7. VBB 8. DATAOUT 9. DATAIN 10. NC No connect 11. NC No connect 12. NC No connect 13. VCC 5 V logic supply. The internal latches and registers are set to zero on the rising edge of this signal. 14. OE Output drivers are turned off when this input is low. 15. SCLK Serial clock input. Data is loaded into the part on the rising edge of SCLK. Data is shifted out of DATAOUT on the falling edge of SCLK. CS Active high chip select input. When CS is high, the part is enabled to receive a new serial input word. The high-to-low transition of CS loads the new 20-bit word into the DAC registers and updates the output. 17. NC No connect 18. NC No connect ST Status output. This is an open drain output and goes low when the coil output buffers (C1+, C1–, C2+, C2–, COM) have been disabled. The coil outputs may be disabled due to shorted outputs, over-temperature conditions, power-on reset, or by the output enable (OE) pin. Multiple status outputs , ST, may be wire OR’ed together. 16. 19. Function Ground for VBB supply. Pins 6, 20 and 23 should be connected on the circuit board. Analog supply. Nominally 13.5 V. Serial data output. Output of the internal shift register. When a new data word is shifted in, the old word is shifted out the DATAOUT pin. DATAOUT output is always active. Serial data input. A new data word is serially shifted into the part on the rising edge of SCLK. The data is shifted in MSB first, gauge 1 first. 20. DGND 21. NC Ground for VCC supply. Connect to Pins 6 and 23. No connect 22. NC No connect 23. AGND Ground for VBB supply. Connect to Pins 6 and 20. 24. COM Output drive for biased coils. This output will be 1/2 of VBB. 25. NC No connect 26. NC No connect 27. C2– Negative output connection to the TAN coil of meter #2. 28. C2+ Positive output connection to the TAN coil of meter #2. ABSOLUTE MAXIMUM RATINGS SYMBOL PARAMETER RATING UNIT VBB Analog supply -1 to +23 V VCC Digital supply -1 to +6 V VIN Digital input voltage, Data In, OE, CS, SCLK -1 to +6 V DGND to AGND Ground difference ±0.5 V TA Ambient operating temperature –40 to +85 °C TJ Junction temperature 150 °C TSTG Storage temperature –65 to +150 °C 1500 mW 90 °C/W PD Power dissipation (TA = θJA DIP and SO packages 25°C)1 N, D packages NOTE: 1. For power dissipation ratings in still air, derate above 25°C at the following rates: N and D packages at 12mW/°C 1999 Sep 20 4 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A DC ELECTRICAL CHARACTERISTICS VBB = 7.5 to 18 V; VCC = 4.5 to 5.5 V; TA = –40 to +85°C. SYMBOL VBB PARAMETER TEST CONDITIONS Analog supply voltage LIMITS MIN TYP 7.5 18 VIGN = 18 V no load VBB = 18 V with load RC1 = RC2 = RLMIN IIGN Analog supply current ICC Logic supply current VCC = 5.5 V VOH Output high voltage Data out IOH = 800 µA VOL Output low voltage MAX UNIT V 30 mA 235 1.0 mA V VCC – 0.8 Data out IOL = 1.5 mA 0.4 VOL Status ST, IOL = 2.5 mA 0.8 V IOH Status ST, VO (ST) = VCC 25 µA VIH Input high voltage CS, SCLK, DATAIN, OE VIL Input low voltage CS, SCLK, DATAIN, OE 0.3 x VCC V IIH Input high current CS, SCLK, DATAIN, VIN = 0.7 x VCC 1 µA IIL Input low current CS, SCLK, DATAIN, VIN = 0.3 x VCC 1 µA ACC Output function accuracy2 RC1 = RC2 = RLMIN ±1 Degree 85 43 85 43 500 300 500 300 mA mA mA mA VBB = VBB (MAX) RL = RL (MIN) 0.7 x VBB 0.8 x VBB V TA = 85°C TA = 25°C TA = –40°C 215 171 138 IOB (Source or Sink) RL = RL (MIN) 0.475 x VBB ISD Output shut-down current VDRIVE Differential coil drive voltage1 RLMIN Minimum load resistance VBIAS Bias voltage3 C1+, C1–, C2+, C2–, COM ISINK VBB = VBB (MAX) VBB = VBB (MIN) ISOURCE VBB = VBB (MAX) VBB = VBB (MIN) 0.7 x VCC V Ω Ω Ω 0.525 x VBB V NOTE: 1. VDRIVE is the maximum voltage that is applied across the coil, it is equal to (C1+) – (C1–) or (C2+) – (C2–). 2. In reference to nominal values in Figure 4. (Based on 7+ bit DAC). 3. Output Angle (0) + tan –1 (C )) – (C–) V BB – V BIAS ƪ ƫ AC ELECTRICAL CHARACTERISTICS VDD = 7.5 to 18 V; VCC = 4.5 to 5.5 V; TA = –40 to +85°C SYMBOL PARAMETER TEST CONDITIONS LIMITS MIN TYP MAX FSCLK Input frequency TSCLKH SCLK high time TSCLKL SCLK low time TRO Output rise time DO 0.75 to VCC –1.2 V, CL = 90 pF 75 ns TFO Output fall time DO VCC –1.2 V to 0.75, CL = 90 pF 75 ns TSU DI set-up time 75 ns THI DI hold time 75 ns TCSH Time before first SCLK rising edge 75 ns TCSL Time after last SCLK falling edge 75 ns 1999 Sep 20 1.60 UNIT 175 VCC = 5.5 V 5 MHz ns 175 ns Philips Semiconductors Product specification Dual air-core gauge driver SA5777A maintain the meter accuracy at this maximum deflection. The 0.5 x VBB bias coil voltage is obtained by connecting the bias coils of the two meters in series across VBB. This gives bias stability over temperature. The internal bias generator is used to offset any inaccuracies due to meter mismatches. This circuit receives commands via an internal serial data interface port which is SPI compatible. These parts can be serially cascaded with other SA5777A ICs and/or SA5775A ICs to interface signals in multi-chip systems. The SA5777A has a typical resolution of 0.35° over a full scale deflection of approximately 112° and is guaranteed to be monotonic. The input data is directly proportional to the displayed angle in degrees (Figure NO TAG). Input code 0 gives an output angle of 0°, code 319 (decimal) will generate a full scale output of 112.15°. Codes higher than decimal 319 will not be loaded into the DAC latches and will leave the coil output buffers unchanged. However, codes greater than 319 can be shifted through the SA5777A intact if other parts are cascaded. The SA5777A is capable of sourcing and sinking up to 100mA per differential driver to control either one or two air-core gauge displays directly. FUNCTIONAL DESCRIPTION The SA5777A dual air-core gauge driver logic Block Diagram shows the two 10-bit input shift registers and two 9-bit parallel latches, and two 7+-bit DACs. The MSB is a dummy bit required for compatibility with the SA5775A. The DACs generate output voltages that are offset within the supply rails to give the output buffers enough headroom to operate. With a 14 V supply, the typical output swing is from 1 V to 11.5 V. The MUX generates the two required quadrants by switching the 56° data from the DAC to the appropriate output buffer. The output buffers provide the necessary current to drive the air-core gauge. The output buffers are always connected to the coils and can sink and source sufficient current so that inductive kickback is eliminated during normal operation. The primary function of the SA5777A IC is to generate the transfer function that maps an input code into the correct voltages for linearly controlling the coils of an air-core gauge display (Figure 3). The SA5777A has been implemented using the tangent drive algorithm. Therefore, one coil on each meter will be driven with an output approximating the tangent function, the other coils will be biased at 1/2 VBB. The internal DAC is designed to operate over a 7+ bit (56°) data range. An extended range can be achieved by changing the relationship between the bias coil and the driver coil. As the current through the bias coil is reduced, the full scale deflection is increased. Theoretically, this deflection could approach 180°, but practical limitations of accuracy, resolution, and torque restrict the full scale range to approximately 112° (Figure 4). This full scale range corresponds to a bias coil voltage of 0.5 x VBB and a full scale tangent voltage of 0.744 x VBB. The DAC has been tailored to On-chip overcurrent and thermal shut-down logic prevents the chip from overheating due to high current fault conditions. When a shut-down condition is detected, the protection circuit disables the coil output buffers (i.e., C1+, C1–, C2+, C2–, COM). The coil output buffers remain in this condition until the first falling edge of CS that occurs after the die temperature has decreased to about 140°C or the overcurrent condition has been removed. During shut-down, the digital portion of this IC continues to operate normally. 14.00 12.00 10.00 8.00 C+ – C– (VOLTS) 6.00 4.00 2.00 0.00 –2.00 –4.00 31 63 95 127 159 191 223 255 287 319 INPUT CODE –6.00 –8.00 –10.00 –12.00 –14.00 SL00462 Figure 3. Typical output voltage vs input code (VBB = 14 V) 1999 Sep 20 6 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A ASSUMING CODE 0 IS 0°: 0.5 x VBB CODE –56° –56.097 31 –45.194 63 –33.940 95 –22.685 127 –11.430 159 –0.176 +56° –0.744 x VBB 0.744 x VBB TOTAL SPAN = 112.15° STEP SIZE = 0.35° POSITION 0 191 11.079 223 22.333 255 33.588 287 44.843 319 56.097 IDEAL ANGLE(DEGREE)=CODE/319*2* ArcTan (0.744/0.5)–ArcTan(0.744/0.5) SL00463 Figure 4. Total span 120 100 ANGLE (DEGREES) 80 60 40 20 0 0 15 31 41 63 79 95 111 127 159 175 143 INPUT CODE 191 207 223 239 255 271 287 303 319 SL00464 Figure 5. Meter position (degrees) vs input code 1999 Sep 20 7 Philips Semiconductors Product specification Dual air-core gauge driver SA5777A CS 20 SCLK CYCLES FSCLK TCSH 1 2 TSCLKL 19 20 TSCLKH SCLK TCSL 80% DATAIN D19 D18 D1 D0 20% THI TSU D19* DATAOUT D18* TFO D1* TRO GAUGE 2 D0 D1 D2 D3 D4 D0* GAUGE 1 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 D17 D18 D19 MSB LSB LSB MSB *DO IS THE PREVIOUSLY LOADED DATA WORD SL00465 Figure 6. Serial interface timing Serial Interface The SA5777A is controlled through a serial interface with the following control functions (reference Figure 6): SCLK Serial input clock. When CS is high, the rising edge of SCLK shifts a new data bit into the SA5777A and the falling edge shifts the data out of DATAOUT. CS Active high chip select. Enables the SA5777A to receive serial input data. The falling edge of CS loads a new 20-bit data word into the internal DAC registers which updates the tangent coil output buffers (C1+, C1–, C2+, C2–). DATAIN Serial data input. The data at this pin is shifted into the internal shift register on the rising edge of SCLK. Data is shifted in MSB first, gauge 1 first. DATAOUT Serial data output. This pin is the output of the internal shift register. The data output on this pin is the input data from DATAIN pin delayed by 20 clock cycles. This pin can be used to cascade several SA5777As with one CS line to load all of the SA5777As concurrently. The SA5777A has a power-on reset capability. On the rising edge of VCC, the internal latches and registers are set to zero and the coil output buffers (C1+, C1–, C2+, C2–, COM) are disabled. 4. Due to excessive power dissipation (i.e., thermal shut-down). The die temperature must go below 140°C before a falling edge on the CS pin will clear this fault condition and allow the coil outputs to go active. Coil Output Buffer Control Application Notes Power Moding The coil buffers (C1+, C1–, C2+, C2–, COM) are disabled: 1. With the rising edge of VCC (power-on reset). The air-core gauge is constructed of two coils would on a cavity at 90° to each other. Inside the cavity there is a disk which is magnetized on its diameter. The currents through the coils generate a resultant magnetic vector that causes the magnetic disc to move until the magnetic fields are aligned. If the ratio of the currents in the two coils follows the tangent function, then the transfer characteristic relating the input data to output angle is linear. 2. When OE is taken low or held low. The data registers for the outputs can still be updated while OE is low. When OE is taken high, the current output data value is displayed. A falling edge on CS will be required to activate the outputs if a fault condition has occurred prior to the OE going high. Maximum current is when output is at zero and full scale degrees, TA = –40°C, and RL = 180. 3. Due to an overcurrent condition on either of the coil output buffers. The coil output buffers will be enabled after the next CS high-to-low transition; assuming OE is high. If the overcurrent condition has not been removed, the outputs will immediately return to their disabled condition. The ST pin will indicate status of the coil outputs. 1999 Sep 20 Copper wire has a typical temperature coefficient of 0.4%/C 8 Philips Semiconductors Product specification Dual air–core gauge driver SA5777A DIP16: plastic dual in-line package; 16 leads (300 mil) 1999 Sep 20 9 SOT38-4 Philips Semiconductors Product specification Dual air–core gauge driver SA5777A SO28: plastic small outline package; 28 leads; body width 7.5mm 1999 Sep 20 10 SOT136-1 Philips Semiconductors Product specification Dual air–core gauge driver SA5777A NOTES 1999 Sep 20 11 Philips Semiconductors Product specification Dual air–core gauge driver SA5777A Data sheet status Data sheet status Product status Definition [1] Objective specification Development This data sheet contains the design target or goal specifications for product development. Specification may change in any manner without notice. Preliminary specification Qualification This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips Semiconductors reserves the right to make changes at any time without notice in order to improve design and supply the best possible product. Product specification Production This data sheet contains final specifications. Philips Semiconductors reserves the right to make changes at any time without notice in order to improve design and supply the best possible product. [1] Please consult the most recently issued datasheet before initiating or completing a design. Definitions Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Disclaimers Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Copyright Philips Electronics North America Corporation 1999 All rights reserved. Printed in U.S.A. Philips Semiconductors 811 East Arques Avenue P.O. Box 3409 Sunnyvale, California 94088–3409 Telephone 800-234-7381 Date of release: 09-99 Document order number: 1999 Sep 20 12 9397 750 06444