TS9514

TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Integrated Analog Front-End for Heart Rate Monitors and Low-Cost Pulse Oximeters Features Applications • Fully-Integrated Analog Front-End for Pulse • Low-Cost Medical Pulse Oximeter Applications Oximeter Applications • Optical HRM • Receiver:  High Accuracy Current to Frequency Converter up to 500KHz The TS9514 is a fully-integrated analog front-end • Transmitter: (AFE) that is ideally suited for pulse Oximeter  Flexible Pulse Sequencing and Timing Control applications. The device consists of a low-noise I/F with Integrated LED Driver (H-Bridge) converter and a LED transmitter section. The I/F  95dB Dynamic Range converter converts photodiode current to frequency  LED Currents Programmable with an External signal. The LED transmitter currents can be easily  Resistor and Analog Input Voltages controlled through analog input voltages. The • Power Supplies: 2.5V to 5.5V TS9514’s flexibility allows users to have complete  Low Power: 1.25 mA at 3.3V Supply control of the device’s timing characteristics. The • Specified Temperature Range: -40°C to +85°C TS9514 is an AFE solution in TSSOP14 and QFN16 • Package: TSSOP14, QFN16 packages and is specified over the operating Product Description temperature from -40°C to +85°C. VDD=2.5V~5.5V PVDD=2.5V~5.5V U2 VDD PVDD U1 OUT RED_CS IR_CS C1 0.1uF ANOD R1 MCU IN IR RED_REF R2 R3 NC IR_REF GND RED PROG RPROG 4Ω REV KY.1.0.4 www.trusignal.com C3 C2 100uF 0.1uF TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Ordering Information Product Package-Lead Package Option Package Qty. Operating Temperature Range TS9514EQR QFN16 Tape and Reel 2500 -40°C to +85°C TS9514ETR TSSOP14 Tape and Reel 2500 -40°C to +85°C Absolute Maximum Ratings ESD CAUTION Over operating free-air temperature range, unless otherwise noted. Value Unit 2.5 to 5.5 V Input current to any pin except supply pins ±10 mA Momentary ±50 mA Continuous ±10 mA -40 to +85 °C –65 to +150 °C +125 °C ±2000 V ±200 V ±500 V VDD to GND Input current Operating temperature range Storage temperature range Maximum junction temperature, TJ Human body model (HBM) Electrostatic Machine model discharge (MM) (ESD) ratings Charge device model(CDM) ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjects to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality. PIN Configuration VDD NC 4 11 PVDD RED_CS 5 10 IR IR_CS 6 9 RED GND 7 8 PROG TSSOP14 REV KY.1.0.4 13 VDD 12 OUT 1 12 RED RED_REF 2 11 IR IR_REF 3 10 PROG NC 4 9 8 3 NC IR_REF 14 PVDD ANOD 7 13 GND 2 6 RED_REF IR_CS IN 16 IN 14 5 1 RED_CS OUT 15 ANOD TS9514 TS9514 NC QFN16 2 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Table 1. PIN Descriptions NO. （TSSOP14） NO. （QFN16） Name Function Description 1 1 OUT Output Frequency output 2 2 RED_REF Input RED LED driver reference voltage input 3 3 IR_REF Input IR LED driver reference voltage input 4 4,8,9 NC Input No connection pin 5 5 RED_CS Input RED LED control input. High active 6 6 IR_CS Input IR LED Control Input. High active 7 7 GND Supply Supply ground pin 8 10 PROG I/O LED driver current program pin, connect a resistor to this Pin 9 12 RED Output RED LED drive output 10 11 IR Output IR LED drive output 11 14 PVDD Supply LED driver power supply pin 12 13 VDD Supply Power supply pin 13 15 ANOD Input Current input, connect to PIN diode anode 14 16 IN Input Current input, connect to PIN diode cathode REV KY.1.0.4 3 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Electrical Characteristics Minimum and maximum specification are at TA=-40°C to +85°C. Typical specifications are at +25°C. All specifications are at VDD=3.3V, unless otherwise noticed. Parameter Test Conditions Min 0°C to +85°C -40°C to +85°C Typ Max Unit 2.5 5.5 V 2.7 5.5 V 2.5 5.5 V 1.7 mA 1000 SPS Performance (Full-Signal Chain) VDD Receiver supply voltage PVDD LED driver supply voltage IDD Supply current PRF Pulse repetition frequency 1 TA=25°C, VDD=5.5V 1.25 I-F Transimpedance Amplifier fO Output frequency IIN=1uA Full-scale frequency 100 500 Nonlinearity fO =0 to 100kHz Re Current responsivity PSRR Power-supply rejection ratio fO=100kHz kHz 1000 kHz ±1% %FS 100 kHz/A 0.3 %/V 200 mA Transmitter 1 Full-scale output current VCONTROL TA=25°C, VDD=5V, RPROG=4Ω; VCONTROL=0.8V Analog input voltage 0 VDD-2 V 1.25 mA VDD=5V,RPROG=4Ω 0.25 Transmitter noise dynamic At 5mA output current TBD dB range, over 0.1Hz to 5Hz At 25mA output current TBD dB bandwidth At 50mA output current TBD dB 50 µs Output current offset Minimum on time of LEDs LED current linearity vs analog input voltage Percent of full-scale current 1% From 0 to 50 mA TBD µs From 50 mA to 0 TBD µs Output current settling time Temperature Specified temperature range -40 +85 ℃ Storage temperature range -65 +150 ℃ 1. The Maximum LED output current depends on PVDD, RPROG resistance and LED forward voltage strongly; it can be smaller than the full-scale current. REV KY.1.0.4 4 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Overview The TS9514 is a complete analog front-end (AFE) circuit targeting pulse oximeter applications. The device consists of a low-noise I/F converter and a LED transmitter section. The I/F converter converts the photodiode current to frequency signal precisely. The output of the device connects directly to a high resolution timer of the external microcontroller (MCU) for which an A/D converter is not necessary. The LED transmitter current can be adjusted through analog input voltages. Figure 1. Timing of LED Control. Receiver The receiver consists of a high LED Current Control precision current-to-frequency (I/F) converter section. The I/F The output currents of the transmitter are controlled by converter the analog input voltages and are given by the converts the photodiode current to frequency signal with high dynamic range and linearity. following equation: The converter continuously converts input current to frequency without being interrupted by the LED control signals. where VREF is the voltage at RED_REF or IR_REF pin. The voltages at RED_REF pin and IR_REF pin control Transmitter Section the RED LED current and IR LED current respectively The transmitter section integrates a voltage controlled and independently. constant current source, an H-bridge LED driver and its control logic. Two LED driver schemes are Timing Diagram of the Transmitter supported: an H-bridge drive for a two-terminal Figure 1 shows the timing diagram for the LED back-to-back LED package and a push-pull drive for a transmitter control. Through the internal logic, signals three-terminal LED package. The on-off of the LED at the RED_CS and IR_CS pins control the switches current is controlled by logic signals at the input pins of the H-Bridge. In T1 and T3 cycles, both LEDs are of RED_CS and IR_CS, and each LED current can be turned off. In T2 and T4 cycles, RED LED and IR LED adjusted by the corresponding analog input voltage are turned on respectively. Both of the RED_CS and independently. An external resistor RPROG at the IR_CS pins are active ‘high’, however, when both are PROG pin sets the ratio of the input voltage to the high at the same time, there will be no current flow LED current and the maximum output current is through the two-terminal back-to-back packaged primarily dependent on RPROG, the power supply LEDs (see Table 2 and Table 3). voltage PVDD, and the forward voltage of the LEDs. REV KY.1.0.4 5 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Table 2. Transmitter True Table ( two-terminal back-to-back packaged LEDs) Inputs Outputs RED_CS IR_CS RED IR RED Transmit IR Transmit 0 0 Z Z OFF OFF 1 0 H L ON OFF 0 1 L H OFF ON 1 1 H H OFF OFF Table 3. Timing Requirements Parameter Min Typ Max Unit tRED_CS Red LED on time, active high 50 s tIR_CS Infrared LED on time, active high 50 s tINT The time interval between Red LED on and IR LED on 50 s REV KY.1.0.4 6 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Application Examples Figure 2 and Figure 3 show the typical application circuit of TS9514 as an analog front-end for Pulse Oximeters. Please note that the pins of RED and IR and pins of VDD and PVDD are interchanged between the two packages. VDD=2.5V~5.5V 1 5 6 C1 0.1uF 11 VDD U1 PVDD 12 PVDD=2.5V~5.5V OUT RED_CS IR_CS IN ANOD R1 MCU U2 IR 2 13 C3 C2 10 100uF 0.1uF 15 C3 C2 11 100uF 0.1uF RED_REF R2 RED 9 8 RPROG 7 4 R3 PROG GND IR_REF NC 3 14 4Ω Figure 2. Typical Application of TS9514 in TSSOP14 Package. VDD=2.5V~5.5V OUT RED_CS IR_CS IN ANOD R1 MCU U2 IR 2 RED_REF R2 NC 8 4 R3 7 NC IR_REF GND RED 3 16 PROG 12 10 9 NC C1 0.1uF PVDD 1 5 6 VDD U1 14 13 PVDD=2.5V~5.5V RPROG 4Ω Figure 3. Typical Application of TS9514 in QFN16 Package. REV KY.1.0.4 7 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 Mechanical Dimensions TSSOP-14 PACKAGE MECHANICAL DRAWING θ TSSOP-14 PACKAGE MECHANICAL DATA dimensions symbol millimeters min max min max A 6.2 6.6 0.2441 0.2598 A1 4.3 4.5 0.1693 0.1772 B 4.9 5.1 0.1929 0.2008 B1 B2 0.65 0.19 C 0.0256 0.3 0.0075 1.20MAX 0.0118 0.0472MAX C1 0.05 0.15 0.0020 0.0059 L 0.5 0.75 0.0197 0.0295 D 0.1 0.2 0.0039 0.0079 θ REV KY.1.0.4 inches 0 o 8 8 o 0 o 8 o www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 QFN-16 PACKAGE MECHANICAL DRAWING D e N16 k L N13 E E1 N1 D1 N9 N5 b Bottom View A1 A A3 TOP View Side View QFN-16 PACKAGE MECHANICAL DATA dimensions symbol millimeters min max min max A 0.700/0.800 0.800/0.900 0.028/0.031 0.031/0.035 A1 0.000 0.050 0.000 0.002 A3 0.203REF. 0.008REF. D 2.924 3.076 0.115 0.121 E 2.924 3.076 0.115 0.121 D1 1.600 1.800 0.063 0.071 E1 1.600 1.800 0.063 0.071 k b 0.200MIN. 0.180 e L REV KY.1.0.4 inches 0.008MIN 0.280 0.007 0.500TYP. 0.324 0.011 0.020TYP. 0.476 9 0.013 0.019 www.trusignal.com TS9514 Trusignal Microelectronics APRIL 2014 - REVISED AUGUST 2014 CONTACT INFORMATION Trusignal Microelectronics 328 Xinghu Street, Suite 22-207, Suzhou Industrial Park, Suzhou, 215123, PR China Email: support@trusignal.com; sales@trusignal.com Phone: +86 512-65923982 Fax: +86 512-65923995 REV KY.1.0.4 10 www.trusignal.com