ML2035

February 1997 ML2035 Serial Input Programmable Sine Wave Generator GENERAL DESCRIPTION The ML2035 is a monolithic sinewave generator whose output is programmable from DC to 25kHz. No external components are required. The frequency of the sinewave output is derived from either an external crystal or clock input, providing a stable and accurate frequency reference. The frequency is programmed by a 16-bit serial data word. The ML2035 has a VOUT amplitude of ±VCC/2. The ML2035 is intended for telecommunications and modem applications that need low cost and accurate generation of precise test tones, call progress tones, and signaling tones. FEATURES s s s Programmable output frequency - DC to 25kHz Low gain error and total harmonic distortion 3-wire SPI compatible serial microprocessor interface with double buffered data latch Fully integrated solution - no external components required Frequency resolution of 1.5Hz (±0.75Hz) with a 12MHz clock input Onboard 3 to 12MHz crystal oscillator Synchronous or asynchronous data loading capability Compatible with ML2031 and ML2032 tone detectors and ML2004 logarithmic gain/attenuator s s s s s BLOCK DIAGRAM 5kΩ 5kΩ CLK IN 8 - VOUT CRYSTAL OSCILLATOR 8-BIT DAC 8 PHASE ACCUMULATOR & 512 POINT SINE LOOK-UP TABLE 16 16-BIT DATA LATCH SMOOTHING FILTER 6 + VCC 5 ÷4 ZERO DETECT GND 7 LATI 4 VSS SCK 2 16 16-BIT SHIFT REGISTER 1 SID 3 1 ML2035 PIN CONFIGURATION ML2035 8-Pin PDIP (P08) VSS 1 SCK 2 SID 3 LATI 4 8 7 6 5 CLK IN GND VOUT VCC TOP VIEW PIN DESCRIPTION PIN NAME FUNCTION PIN NAME FUNCTION 1 2 VSS SCK Negative supply (-5V). Serial clock. Digital input which clocks in serial data on its rising edges. Serial input data which programs the frequency of VOUT. Digital input which latches serial data into the internal data latch on falling edges. 5 6 7 8 VCC VOUT GND CLK IN Positive supply (5V). Analog output. VOUT swing is ±VCC/2. Ground. All inputs and outputs are referenced to this point. Clock input. The internal clock can be generated by tying a 3 to 12MHz crystal from this pin to GND, or applying a digital clock signal directly to the pin. 3 4 SID LATI 2 ML2035 ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. VCC .............................................................................................. 6.5V VSS ............................................................................................. -6.5V VOUT .................................................... VSS - 0.3V to VCC + 0.3V Voltage on any other pin ........ GND - 0.3V to VCC + 0.3V Input Current ........................................................ ±25mA Junction Temperature .............................................. 150ºC Storage Temperature Range ...................... –65ºC to 150ºC Lead Temperature (Soldering, 10 sec) ...................... 260ºC Thermal Resistance (qJA) .................................... 110ºC/W OPERATING CONDITIONS Temperature Range ML2035CP ................................................. 0ºC to 70ºC ML2035IP ............................................... -40ºC to 85ºC VCC Range ................................................... 4.5V to 5.5V VSS Range ................................................. -4.5V to -5.5V ELECTRICAL CHARACTERISTICS Unless otherwise specified, VCC = 4.5V to 5.5V, VSS = -4.5V to -5.5V, CLK IN = 12.352MHz, CL = 100pF, RL = 1kW, TA = Operating Temperature Range (Note 1) SYMBOL OUTPUT HD Harmonic Distortion (2nd and 3rd Harmonic) SND Signal to Noise + Distortion 20Hz to 5kHz 5kHz to 25kHz 200Hz to 3.4kHz, fOUT BW = 20Hz to 4kHz 20Hz to 25kHz, fOUT BW = 20 Hz to 75kHz VGN Gain Error 20Hz < fOUT < 5kHz 5kHz < fOUT < 25kHz ICN Idle Channel Noise Power Down Mode, Cmsg Weighted Power Down Mode, 1kHz PSRR Power Supply Rejection Ratio 200mVP-P, 0 - 10kHz Sine, Measured on VOUT VOS VP-P VOUT Offset Voltage Peak-to-Peak Output Voltage ±VCC/2 VCC VSS -20 50 -40 -40 ±75 -45 -40 -45 -40 ±0.15 ±0.3 0 dB dB dB dB dB dB dBrnc nV/ÖHz dB dB mV V PARAMETER CONDITIONS MIN TYP MAX UNITS OSCILLATOR VIL CLK VIH CLK IIL CLK IIH CLK CIN CLK tCKI CLK IN Input Low Voltage CLK IN Input High Voltage CLK IN Input Low Current CLK IN Input High Current CLK IN Input Capacitance CLK IN On/Off Period tR = tF = 10ns, 2.5V Midpoint 30 12 3.5 -250 250 1.5 V V µA µA pF ns LOGIC (LATI, SID, SCK) VIL VIH IIL IIH Input Low Voltage Input High Voltage Input Low Current Input High Current VIN = 0V VIN = VCC 2.0 -1 1 0.8 V V µA µA 3 ML2035 ELECTRICAL CHARACTERISTICS SYMBOL LOGIC (Continued) VOL VOH tSCK tDS tDH tLPW tLH tLS SUPPLY ICC VCC Current No Load, VCC = 5.5V No Load, Power Down Mode ISS VSS Current No Load, VCC = 5.5V, VSS = -5.5V No Load, Power Down Mode Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. (Continued) CONDITIONS MIN TYP MAX UNITS PARAMETER Output Low Voltage Output High Voltage Serial Clock On/Off Period SID Data Setup Time SID Data Hold Time LATI Pulse Width LATI Hold Time LATI Setup Time IOL = -2mA IOH = 2mA 4.0 100 50 50 50 50 50 0.4 V V ns ns ns ns ns ns 5.5 2 -3.5 -100 mA mA mA µA 100 tCKI CLK IN tSCK SCK tDS SID tDH tCKI 75 50 tSCK INPUT CURRENT (µA) tLH 25 0 -25 -50 -75 -100 tLS LATI tLPW 0 1 2 3 4 5 INPUT VOLTAGE (V) Figure 1. Serial Interface Timing. Figure 2. CLK IN Input Current vs. Input Voltage. 4 ML2035 FUNCTIONAL DESCRIPTION The ML2035 is composed of a programmable frequency generator, a sine wave generator, a crystal oscillator, and a serial digital interface. The ML2035 frequency and sine wave generator functional block diagram is shown in Figure 3. PROGRAMMABLE FREQUENCY GENERATOR The programmable frequency generator produces a digital output whose frequency is determined by a 16-bit digital word. The frequency generator is composed of a phase accumulator which is clocked at fCLK IN/4. The value stored in the data latch is added to the phase accumulator every 4 cycles of CLK IN. The frequency of the analog output is equal to the rate at which the accumulator overflows and is given by the equation: fOUT = fCLKIN × (D15 - D0)DEC 223 (1) (3) For example, if VOUT(P-P) = 2.5V: must be limited to 25kHz for VCC = 5V. VOUT can drive a 1kW, 100pF loads, provided the slew rate limitations mentioned above are not exceeded. The output offset voltage, VOS, is a function of the peak-topeak output voltage and is specified as: CRYSTAL OSCILLATOR The crystal oscillator generates an accurate reference clock for the programmable frequency generator. The internal clock can be generated with a crystal or external clock. If a crystal is used, it must be placed between CLK IN and GND of the ML2035. An on-chip crystal oscillator will then generate the internal clock. No other external capacitors or components are required. The crystal should be a parallel-resonant type with a frequency between 3MHz to 12.4MHz. It should be placed physically as close as possible to the CLK IN and GND. An external clock can drive CLK IN directly if desired. The frequency of this clock can be anywhere between 0 and 12MHz. The crystal must have the following characteristics: 1. Parallel resonant type 2. Frequency: 3MHz to 12.4MHz 3. Maximum equivalent series resistance of 15W at a drive levels of 1µW to 200µW, and 30W at drive levels of 10nW to 1µW 4. Typical load capacitance: 18pF 5. Maximum case capacitance: 7pF The frequency of oscillation will be a function of the crystal parameters and PC board capacitance. Crystals that meet these requirements at 12.352000MHz are M-tron 3709-010 12.352 for 0ºC to 70ºC and 3709-020 12.352 for -40ºC to 85ºC operation. The frequency resolution and the minimum frequency are the same and is given by the following equation: f ∆fMIN = CLKIN (2) 223 When fCLK IN = 12.352MHz, DfMIN = 1.5Hz (±0.75Hz). Lower frequencies are obtained by using a lower input clock frequency. Due to the phase quantization nature of the frequency generator, spurious tones can be present in the output range of –55dB relative to fundamental. The energy from these tones is included in the signal to noise + distortion specification. The frequency of these tones can be very close to the fundamental. Therefore, it is not practical to filter them out. SINEWAVE GENERATOR The sinewave generator is composed of a sine look-up table, a DAC, and an output smoothing filter. The sine look-up table is addressed by the phase accumulator. The DAC is driven by the output of the look-up table and generates a staircase representation of a sine wave. The output filter smoothes the analog output by removing the high frequency sampling components. The resultant voltage on VOUT is a sinusoid with the second and third harmonic distortion components at least 45dB below the fundamental. The ML2035 provides a peak sinewave voltage of ±VCC/2, referenced to GND. The analog section is designed to operate over a range from DC to 25kHz. Due to slew rate limitations, the peakto-peak output voltage must be limited to VOUT(P-P) £ (125kV x Hz)/fOUT. Since the ML2035 peak-to-peak output voltage is equal to VCC, the maximum output frequency 5 ML2035 SID 16-BIT SHIFT REGISTER (16 BITS) ••• LATI 16-BIT DATA LATCH (16 BITS) ••• ••• A16 A0 – A20 A15 21-BIT ADDER B0–B20 BINARY PHASE ACCUMULATOR fREF Q0 – SUM (21 BITS) ••• 21-BIT LATCH ••• INPUT TO QUADRANT COMPLEMENTOR Q20 LEAST SIGNIFICANT (12 BITS) ••• PHASE SAMPLES (7 BITS) SIGN BIT QUADRANT BIT CLK IN CRYSTAL OSCILLATOR ÷4 QUADRANT COMPLEMENTER ••• (7 BITS) READ-ONLY MEMORY (128 X 7) ••• (7 BITS) SIGN COMPLEMENTOR ••• (7 BITS) fREF OUTPUT LATCH ••• (7BITS) SIGN BIT SIGN BIT SIGN BIT T= INPUT TO ROM 1 fREF INPUT TO SIGN COMPLEMENTOR PICTORIAL PRESENTATION OF DIGITAL DATA INPUT TO OUTPUT LATCH INPUT TO D/A CONVERTER 8-BIT DIGITAL-TO-ANALOG CONVERTER LOW-PASS FILTER INPUT TO LOW-PASS FILTER (ANALOG SIGNAL) OUTPUT OF LOW-PASS FILTER (ANALOG SIGNAL) SINEWAVE OUTPUT Figure 3. Detailed Block Diagram of the ML2035. 6 ML2035 SCK SID LATI 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Figure 4. Serial Interface Timing. FUNCTIONAL DESCRIPTION (Continued) SERIAL DIGITAL INTERFACE The digital interface consists of a shift register and data latch. The serial 16-bit data word on SID is clocked into a 16-bit shift register on rising edges of the serial shift clock, SCK. The LSB should be shifted in first and the MSB last as shown in Figure 4. The data that has been shifted into the shift register is loaded into a 16-bit data latch on the falling edge of LATI. To insure that true data is loaded into the data latch from the shift register, LATI falling edge should occur when SCK is low, as shown in figure 1. LATI should be low while shifting data into the shift register to avoid inadvertently entering the power down mode. Note that all data is entered and latched on the edges, not levels, of SCK and LATI. POWER DOWN MODE The power down mode of the ML2035 can be selected by entering all zeros in the shift register and applying a logic “1” to LATI and holding it high. A zero data detect circuit detects when all bits in the shift register are zeros. In this state, the power consumption is reduced to 11.5mW max, and VOUT goes to 0V as shown in Figure 5 and appears as 10kW to ground. The master clock, CLK IN, can be left active or removed during power down mode. POWER SUPPLIES The analog circuits in ML2035 are powered from VCC to VSS and are referenced to GND. The digital circuits in the device are powered from VCC to GND. It is recommended that the power supplies to the device should be bypassed by placing decoupling capacitors from VCC to GND and VSS to GND as physically close to the device as possible. POWER DOWN MODE 0V VOS SCK SID LATI 0 1 2 3 4 5 6 7 8 9 10 11 12 131415 Figure 5. Power Down Mode Waveforms. 7 ML2035 TYPICAL APPLICATIONS RECEIVE LINE INTERFACE ML2003 ML2004 ML2008 ML2009 ATTENUATION /GAIN ML2020 ML2021 LINE EQUALIZER ML2031 ML2032 TONE DETECTOR µP LOOPBACK RELAY TRANSMIT LINE INTERFACE ML2003 ML2004 ML2008 ML2009 ATTENUATION /GAIN ML2035 TONE GENERATOR Figure 6. 4-Wire Termination Equipment. 5V ML2035 0.1µF 0.1µF VSS –5V 0 TO 25kHz SINEWAVE VCC/2 VCC GND VOUT VCC/2 Figure 7. Sine Wave Ratiometric to ±VCC/2. 8 ML2035 PHYSICAL DIMENSIONS inches (millimeters) Package: P08 8-Pin PDIP 0.365 - 0.385 (9.27 - 9.77) 0.055 - 0.065 (1.39 - 1.65) 8 PIN 1 ID 0.240 - 0.260 0.299 - 0.335 (6.09 - 6.60) (7.59 - 8.50) 0.020 MIN (0.51 MIN) (4 PLACES) 1 0.100 BSC (2.54 BSC) 0.015 MIN (0.38 MIN) 0.170 MAX (4.32 MAX) 0.125 MIN (3.18 MIN) 0.016 - 0.020 (0.40 - 0.51) SEATING PLANE 0º - 15º 0.008 - 0.012 (0.20 - 0.31) ORDERING INFORMATION PART NUMBER ML2035CP ML2035IP TEMPERATURE RANGE 0ºC to 70ºC -40ºC to 85ºC PACKAGE 8-Pin PDIP (P08) 8-Pin PDIP (P08) © Micro Linear 1997. is a registered trademark of Micro Linear Corporation. Products described herein may be covered by one or more of the following patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376. Other patents are pending. Micro Linear reserves the right to make changes to any product herein to improve reliability, function or design. Micro Linear does not assume any liability arising out of the application or use of any product described herein, neither does it convey any license under its patent right nor the rights of others. The circuits contained in this data sheet are offered as possible applications only. Micro Linear makes no warranties or representations as to whether the illustrated circuits infringe any intellectual property rights of others, and will accept no responsibility or liability for use of any application herein. The customer is urged to consult with appropriate legal counsel before deciding on a particular application. 2092 Concourse Drive San Jose, CA 95131 Tel: (408) 433-5200 Fax: (408) 432-0295 DS2035-01 9