TS3004 A 1.55V to 5.25V, 1.9µA, 3.3µs to 233s Silicon Timer FEATURES DESCRIPTION The TS3004 is a single-supply, second-generation oscillator/timer fully specified to operate over a supply voltage range of 1.55V to 5.25V while consuming less than 2.4μA(max) supply current. Requiring only a resistor to set the base output frequency (or output period) at 25kHz (or 40µs) with a 50% duty cycle, the TS3004 timer/oscillator is compact, easy-to-use, and versatile. Optimized for ultra-long life, low frequency, battery-powered/portable applications, the TS3004 joins the TS3001, TS3002, TS3003 and TS3006 in the CMOS timer family of “NanoWatt Analog™” highperformance analog integrated circuits. Ultra Low Supply Current: 1.9μA at 25kHz Supply Voltage Operation: 1.55V to 5.25V Single Resistor Sets FOUT at 50% Duty Cycle 3-pin User-Programmable FOUT Period: 3.3µs ≤ tFOUT ≤ 233s FOUT Period Accuracy: 3% FOUT Period Drift: 0.02%/ºC Single Resistor Sets Output Frequency Separate PWM Control and Buffered Output FOUT/PWMOUT Output Driver Resistance: 160Ω APPLICATIONS Portable and Battery-Powered Equipment Low-Parts-Count Nanopower Oscillator Compact Micropower Replacement for Crystal and Ceramic Oscillators Micropower Pulse-width Modulation Control Micropower Pulse-position Modulation Control Micropower Clock Generation Micropower Sequential Timing The TS3004 output period can be user-adjusted from 3.3µs to 233s without additional components. In addition, the TS3004 represents a 25% reduction in pcb area and a factor-of-10 lower power consumption over other CMOS-based integrated circuit oscillators/timers. When compared against industrystandard 555-timer-based products, the TS3004 offers up to 84% reduction in pcb area and over three orders of magnitude lower power consumption. The TS3004 is fully specified over the -40°C to +85°C temperature range and is available in a low-profile, 10-pin 3x3mm TDFN package with an exposed back-side paddle. TYPICAL APPLICATION CIRCUIT TS3004 Flashing Railroad Lights Circuit Page 1 © 2014 Silicon Laboratories, Inc. All rights reserved. TS3004 ABSOLUTE MAXIMUM RATINGS VDD to GND................................................................. -0.3V to +5.5V PWM_CNTRL to GND ................................................ -0.3V to +5.5V FOUT, PWMOUT to GND .......................................... -0.3V to +5.5V RSET to GND............................................................. -0.3V to +2.5V CPWM to GND ........................................................... -0.3V to +5.5V FDIV to GND .............................................................. -0.3V to +5.5V Continuous Power Dissipation (TA = +70°C) 10-Pin TDFN (Derate at 13.48mW/°C above +70°C) ... 1078mW Operating Temperature Range ................................. -40°C to +85°C Storage Temperature Range .................................. -65°C to +150°C Lead Temperature (Soldering, 10s)...................................... +300°C Electrical and thermal stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to any absolute maximum rating conditions for extended periods may affect device reliability and lifetime. PACKAGE/ORDERING INFORMATION ORDER NUMBER PART CARRIER QUANTITY MARKING TS3004ITD1033 Tape & Reel ----- Tape & Reel 3000 3004I TS3004ITD1033T Lead-free Program: Silicon Labs supplies only lead-free packaging. Consult Silicon Labs for products specified with wider operating temperature ranges. Page 2 TS3004 Rev. 1.0 TS3004 ELECTRICAL CHARACTERISTICS VDD = 3V, VPWM_CNTRL= VDD, RSET = 4.32MΩ, RLOAD(FOUT) = Open Circuit, CLOAD(FOUT) = 0pF, CLOAD(PWM) = 0pF, CPWM = 47pF, FDIV2:0 = 000 unless otherwise noted. Values are at TA = 25°C unless otherwise noted. See Note 1. PARAMETER Supply Voltage SYMBOL VDD CONDITIONS CPWM = VDD Supply Current IDD MIN 1.55 TYP 1.9 -40°C ≤ TA ≤ 85°C 3.3 -40°C ≤ TA ≤ 85°C FOUT Period FOUT Period Line Regulation tFOUT ∆tFOUT/V -40°C ≤ TA ≤ 85°C 1.55V ≤ VDD ≤ 5.25V 49 ∆tFOUT/∆T PWMOUT Duty Cycle DC(PWMOUT) PWMOUT Duty Cycle Line Regulation ΔDC(PWMOUT)/V CPWM Sourcing Current ICPWM UVLO Hysteresis FOUT, PWMOUT Rise Time FOUT, PWMOUT Fall Time VUVLO FDIV Input Current 37 15 51 1.55V < VDD < 5.25V, FDIV2:0 = 000 FDIV2:0 = 000, 001 FDIV2:0 000, 001 (VDD=1.55V) – (VDD_SHUTDOWN VOLTAGE) 41.6 930 810 48 24 % % % 1050 1150 97 150 µs %/°C -3 -40°C ≤ TA ≤ 85°C µA %/V 0.02 VPWM_CNTRL= 0V UNITS V 250 nA nA mV tRISE See Note 2, CL = 15pF 10 ns tFALL See Note 2, CL = 15pF 10 ns 0.001 % FOUT Jitter RSET Pin Voltage 40.1 0.17 FOUT Duty cycle FOUT Period Temperature Coefficient 39 38 MAX 5.25 2.4 2.7 3.6 4.5 41.2 42 See Note 3 V(RSET) IFDIV 0.3 V 10 nA -40°C ≤ TA ≤ 85°C 20 Maximum Oscillator Fosc RSET= 360K 300 kHz Frequency High Level Output IOH = 1mA 160 mV Voltage, FOUT and VDD - VOH PWMOUT Low Level Output Voltage, FOUT and VOL IOL = 1mA 140 mV PWMOUT Dead Time TDT FOUT edge falling and PWMOUT edge rising 106 ns Note 1: All devices are 100% production tested at TA = +25°C and are guaranteed by characterization for TA = TMIN to TMAX, as specified. Note 2: Output rise and fall times are measured between the 10% and 90% of the VDD power-supply voltage levels. The specification is based on lab bench characterization and is not tested in production. Note 3: Timing jitter is the ratio of the peak-to-peak variation of the period to the mean of the period. The specification is based on lab bench characterization and is not tested in production. TS3004 Rev. 1.0 Page 3 TS3004 TYPICAL PERFORMANCE CHARACTERISTICS VDD = 3V, VPWM_CNTRL= VDD, RSET = 4.32MΩ, RLOAD(FOUT) = Open Circuit, CLOAD(FOUT) = 0pF, CLOAD(PWM) = 0pF, CPWM = VDD, FDIV2:0 = 000 unless otherwise noted. Values are at TA = 25°C unless otherwise noted. FOUT Period vs Temperature Supply Current vs FOUT Period 14 41 40.5 10 PERIOD - µs SUPPLY CURRENT - µA 12 8 6 4 39.5 2 0 39 0 20 40 60 80 100 -40 35 60 Supply Current vs CLOAD(FOUT) Supply Current vs Temperature 85 2.5 SUPPLY CURRENT - µA SUPPLY CURRENT - µA 10 TEMPERATURE - ºC 6 4 2 2.3 2.1 1.9 1.7 0 0 10 30 20 40 -40 10 35 60 TEMPERATURE - ºC FOUT Period vs Supply Voltage Start-up Time vs Supply Voltage 85 11 START-UP TIME - ms 40.18 40.16 40.14 40.12 40.1 1.55 -15 CLOAD- pF 40.2 10 9 8 7 6 5 2.29 3.03 3.77 4.51 SUPPLY VOLTAGE - Volt Page 4 -15 PERIOD - µs 8 PERIOD - µs 40 5.25 1.55 2.29 3.03 3.77 4.51 5.25 SUPPLY VOLTAGE - Volt TS3004 Rev. 1.0 TS3004 TYPICAL PERFORMANCE CHARACTERISTICS VDD = 3V, VPWM_CNTRL= VDD, RSET = 4.32MΩ, RLOAD(FOUT) = Open Circuit, CLOAD(FOUT) = 0pF, CLOAD(PWM) = 0pF, CPWM = VDD, FDIV2:0 = 000 unless otherwise noted. Values are at TA = 25°C unless otherwise noted. Supply Current Distribution 120 35% 100 30% PERCENT OF UNITS - % PERIOD - µs Period vs RSET 80 60 40 20 25% 20% 15% 10% 5% 0% 0 0 2 4 6 8 10 12 1.95 RSET - MΩ 1.97 1.99 2.01 SUPPLY CURRENT - µA FOUT VDD = 5V, CLOAD = 15pF FOUT 1V/DIV FOUT 1V/DIV FOUT VDD = 3V, CLOAD = 15pF FOUT and PWMOUT VDD = 3V, CLOAD = 15pF, VPWM CNTRL= VDD, CPWM = 47pF FOUT and PWMOUT VDD = 5V, CLOAD = 15pF, VPWM CNTRL= VDD, CPWM = 47pF PWMOUT 2V/DIV PWMOUT 2V/DIV FOUT 2V/DIV 5µs/DIV FOUT 2V/DIV 5µs/DIV 5µs/DIV TS3004 Rev. 1.0 5µs/DIV Page 5 TS3004 PIN FUNCTIONS Page 6 PIN NAME 1 FOUT 2,3,4 FDIV2:0 5 PWMOUT 6 PWM_CNTRL 7 GND 8 CPWM 9 VDD 10 RSET FUNCTION Fixed Frequency Output. A push-pull output stage with an output resistance of 160Ω. FOUT pin swings from GND to VDD. For lowest power operation, capacitance loads should be minimized and resistive loads should be maximized. Frequency Divider Input. Various combinations of these inputs will change the FOUT frequency for a fixed value of RSET. Refer to Table 1. Pulse-width Modulated Output. A push-pull output stage with an output resistance of 160Ω, the PWMOUT pin is wired anti-phase with respect to FOUT and swings from GND to VDD. For lowest power operation, capacitance loads should be minimized and resistive loads should be maximized. PWM Output Pulse Control Pin. Applying a voltage between GND and VRSET will reduce the duty cycle of the PWMOUT output that is set by the capacitor connected to the CPWM pin. Connect PWM_CNTRL to VDD for fixed PWMOUT output pulse time (determined only by capacitor at CPWM). Ground. Connect this pin to the system’s analog ground plane. PWMOUT Pulse Width Programming Capacitance Input. A target capacitance connected from this pin to GND sets the duty cycle of the PMW output. Minimize any stray capacitance on this pin. The voltage on this pin will swing from GND to VRSET. Connect CPWM to VDD to disable PWM function (saves PWM current). Power Supply Voltage Input. The supply voltage range is 1.55V ≤ VDD ≤ 5.25V. Bypass this pin with a 0.1uF ceramic coupling capacitor in close proximity to the TS3004. FOUT Programming Resistor Input. A 4.32MOhm resistor connected from this pin to ground sets the T3004’s internal oscillator’s output period to 40µs (25KHz). For optimal performance, the composition of the RSET resistor shall be consistent with a tolerance of 1% or lower. The RSET pin voltage is approximately 0.3V. TS3004 Rev. 1.0 TS3004 BLOCK DIAGRAM FDIV FOUT (Hz) ICPWM (A) tFOUT(s) 2:0 000 3.3µ-111.1µs 300k-9k 1µ 001 26.4µ-888.88µs 37.5k-1.125k 1µ 010 211.2µ-7.11ms 4.69k-140.62 100n 011 1.7ms-56.88ms 586-17.578 100n 100 13.6ms-455.16ms 73.25-2.197 100n 101 108.8ms-3.64 9.16-0.2746 100n 110 870.4ms-29.15 1.14-0.0343 100n 111 6.99-233 0.143-0.00429 100n Table 1: FOUT and PWMOUT Frequency Range per FDIV2:0 Combination THEORY OF OPERATION The TS3004 is a user-programmable oscillator where the period of the square wave at its FOUT terminal is generated by an external resistor connected to the RSET pin. The output period is given by: tFOUT (s) = 8FDIV2:0 x RSET 1.08E11 Equation 1. FOUT Frequency Calculation where FDIV2:0 = 0 to 7 TS3004 Rev. 1.0 RSET (MΩ) tFOUT(s) 0.360 6.99 1 19.42 2.49 48.35 4.32 83.89 6.81 132.27 9.76 189.39 12 233 Table 2: tFOUT vs RSET for FDIV2:0 = 111(7) Page 7 TS3004 With an RSET = 4.32MΩ and FDIV2:0=111, the FOUT period is approximately 83.89s with a 50% duty cycle. As design aids, Tables 2 lists TS3004’s typical FOUT period for various standard values for RSET and FDIV2:0 = 111(7). The output period can be user-adjusted from 3.3µs to 233s without additional components. Frequency divider inputs FDIV2:0 can be set to a logic state HIGH or LOW in order to set the desired frequency as shown in to Table 1. The TS3004 also provides a separate PWM output signal at its PWMOUT terminal that is anti-phase with respect to FOUT. A dead time of approximately 106ns exists between FOUT and PWMOUT. To adjust the pulse width of the PWMOUT output, a single capacitor can be placed at the CPWM pin. To determine the capacitance needed for a desired pulse width, the following equation is to be used: CPWM(F)= Pulse Width(s) x ICPWM VCPWM ≅300mV Connect CPWM to VDD to disable the PWM function and in turn, save power. Connect PWM_CNTRL to VDD for a fixed PWMOUT output pulse width, which is determined by the CPWM pin capacitor only. APPLICATIONS INFORMATION Minimizing Power Consumption To keep the TS3004’s power consumption low, resistive loads at the FOUT and PWMOUT terminals increase dc power consumption and therefore should be as large as possible. Capacitive loads at the FOUT and PWMOUT terminals increase the TS3004’s transient power consumption and, as well, should be as small as possible. One challenge to minimizing the TS3004’s transient power consumption is the probe capacitance of oscilloscopes and frequency counter instruments. Most instruments exhibit an input capacitance of 15pF or more. Unless buffered, the increase in transient load current can be as much as 400nA. Equation 2. CPWM Capacitor Calculation where ICPWM and VCPWM is the current supplied and voltage applied to the CPWM capacitor, respectively. The pulse width is determined based on the period of FOUT and should never be greater than the period at FOUT. Make sure the PWM_CNTRL pin is set to at least 400mV when calculating the pulse width of PWMOUT. Note VCPWM is approximately 300mV, which is the RSET voltage. Also note that ICPWM is either 1µA or 100nA. Refer to Table 1. The PWMOUT output pulse width can be adjusted further after selecting a CPWM capacitor. This can be achieved by applying a voltage to the PWM_CNTRL pin between VRSET and GND. With a voltage of at least VRSET, the pulse width is set based on Equation 2. For example, with a period of 40µs( 25kHz) a 47pF capacitor at the CPWM pin generates a pulse width of approximately 16µs. This can be calculated using equation 2. By reducing the PWM_CNTRL voltage from VRSET ≅ 300mV to GND, the pulse width is reduced from 16µs to approximately 8µs. This is a pulse width reduction of 50%. Note that as the FOUT frequency increases, the amount of pulse width reduction reduces and vice versa. Furthermore, if the PWMOUT output is half the frequency of the FOUT output, this means your CPWM capacitor is too large and as a result, the pulse width is greater than the FOUT period. In this case, use Equation 2 and reduce the capacitor value to less than the period. Page 8 Figure 1: Using an External Capacitor in Series with Probes Reduces Effective Capacitive Load. To minimize capacitive loading, the technique shown in Figure 1 can be used. In this circuit, the principle of series-connected capacitors can be used to reduce the effective capacitive load at the TS3004’s FOUT and PWMOUT terminals. To determine the optimal value for CEXT once the probe capacitance is known by simply solving for CEXT using the following expression: CEXT = 1 1 CLOAD(EFF) - 1 CPROBE Equation 3:External Capacitor Calculation TS3004 Rev. 1.0 TS3004 For example, if the instrument’s input probe capacitance is 15pF and the desired effective load capacitance at either or both FOUT and PWMOUT terminals is to be ≤5pF, then the value of CEXT should be ≤7.5pF. TS3004 Start-up Time As the TS3004 is powered up, its FOUT terminal (and PWMOUT terminal, if enabled) is active once the applied VDD is higher than 1.55V. Once the applied VDD is higher than 1.55V, the master oscillator achieves steady-state operation within 8ms. Figure 2: 2 Weeks and 2 Days Counter Circuit 2 Weeks and 2 Days Counter Circuit with TS3004 The TS3004 can be configured into a 2 Weeks and 2 Days counter as shown in Figure 2. The circuit is composed of a TS3004 timer and three dual 74VHC393 4-bit counters. The TS3004 divider inputs are set to FDIV2:0 = 111. With an RSET of 4.32MΩ, the FOUT period is approximately 1.4 minutes. The complete circuit consumes approximately 11µA and is powered with a single 3V CR2032 lithium button cell battery. If a longer period is desired, a sixth counter is available in the third 74VHC393. Divide the PWMOUT Output Frequency by Two with the TS3004 Using a single resistor and capacitor, the TS3004 can be configured to a divide by two circuit as shown in Figure 3. To achieve a divide by two function with the TS3004, the pulse width of the PWMOUT output must be at least a factor of 2 greater than the period set at FOUT by resistor RSET. The CPWM capacitor selected must meet this pulse width requirement and can be calculated using Equation 2. In Figure 3, a value of 4.32MΩ for RSET sets the FOUT output period to 40µs. A CPWM capacitor of 265pF was chosen, which sets the pulse width of PWMOUT to Figure 3: Configuring the TS3004 into a Divide by Two Frequency Divider TS3004 Rev. 1.0 Page 9 TS3004 approximately 80µs. This is well above the required minimum pulse width of 40µs. Using the TS3004 and a Potentiometer to Dim an LED Flashing Railroad Lights with the TS3004 The TS3004 can be configured to dim an LED by modulating the pulse width of the PWMOUT output. With the input divider set to FDIV2:0 = 011 and RSET= 2MΩ, the FOUT output frequency is approximately 100Hz (or 10ms period). Refer to Figure 5. The CPWM capacitor was calculated using Equation 2 with a pulse width of 8.1ms. To reduce the pulse width from 8.1ms and in turn, dim the LED, a 1MΩ potentiometer is used. The potentiometer is connected to the PWM_CNTRL pin in a voltage divider configuration. The supply voltage of the circuit is 5V. With only three resistors and two off the shelf LEDs, the TS3004 can be configured into a flashing railroad lights circuit. With the input divider set to FDIV2:0 = 101 and RSET= 3.24MΩ, the FOUT output frequency is 1Hz. Refer to Figure 4. During the time the output is HIGH, only the pull-down LED is on while when the output is LOW, only the pull-up LED is on. The supply voltage of the circuit is 5V. Figure 4: Flashing Railroad Lights with the TS3004 Figure 5: TS3004 Configured to Dim an LED with a Potentiometer . Page 10 TS3004 Rev. 1.0 TS3004 PACKAGE OUTLINE DRAWING 10-Pin TDFN33 Package Outline Drawing (N.B., Drawings are not to scale) Patent Notice Silicon Labs invests in research and development to help our customers differentiate in the market with innovative low-power, small size, analog-intensive mixed-signal solutions. Silicon Labs' extensive patent portfolio is a testament to our unique approach and world-class engineering team. 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