TS9517

TS9517 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 Product Description up to 500KHz The TS9517 is a fully-integrated analog front-end  Automatic Ambient Light Cancellation (AFE) that is ideally suited for pulse Oximeter • Transmitter: applications. The device consists of a low-noise I/F  Flexible Pulse Sequencing and Timing Control converter and a LED transmitter section. The I/F with Integrated LED Driver (H-Bridge) converter converts photodiode current to frequency  LED Currents Programmable with an External signal. The LED transmitter currents can be easily  Resistor and the SPI Interface controlled  7-Bit Resolution with 95dB Dynamic Range TS9517’s flexibility allows users to have complete • Power Supplies: 2.5V to 5.5V control of the device’s timing characteristics. The  Low Power: 1.2 mA at 3.3V Supply TS9517 is an AFE solution in TSSOP16 and QFN16 • Specified Temperature Range: -40°C to +85°C packages and is specified over the operating • Package: TSSOP16, QFN16 temperature from -40°C to +85°C. through SPI™ the interface. VDD=2.5V~5.5V PVDD=2.5V~5.5V U2 VDD OUT PVDD U1 CS C1 0.1uF IN ANOD SDI IR CLK MCU RED_CS RED GND IR_CS COE CAP C4 PROG RPROG 4Ω 0.1uF REV KY.1.0.4 www.trusignal.com C3 C2 100uF 0.1uF The TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 Ordering Information Product Package-Lead Package Option Package Qty. Operating Temperature Range TS9517EQR QFN16 Tape and Reel 5000 -40°C to +85°C TS9517ETR TSSOP16 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 13 VDD 14 PVDD 2 15 ANOD SDI 3 14 VDD OUT 1 12 RED CLK 4 13 PVDD CS 2 11 IR RED_CS 5 12 IR SDI 3 10 PROG IR_CS 6 11 RED CLK 4 9 GND 7 10 PROG COE 8 9 CAP TSSOP16 REV KY.1.0.4 8 CAP COE 7 CS GND IN 6 16 IR_CS 1 5 16 IN OUT RED_CS 15 ANOD TS9517 TS9517 QFN16 2 www.trusignal.com TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 Table 1. PIN Descriptions NO. （TSSOP16） NO. （QFN16） Name Function Description 1 1 OUT Output Frequency output 2 2 CS Input SPI chip select 3 3 SDI Input SPI data input 4 4 CLK Input SPI clock input 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 8 COE Input Ambient light cancellation selection, COE=High, enable ambient light cancellation; COE=Low, disable ambient light cancellation. An internal 200KΩ pull-up resistor at this pin. 9 9 CAP Input Connect a 0.1μF capacitor to GND 10 10 PROG I/O LED driver current program pin, connect a resistor to this Pin 11 12 RED Output RED LED drive output 12 11 IR Output IR LED drive output 13 14 PVDD Supply LED driver power supply pin 14 13 VDD Supply Power supply pin 15 15 ANOD Input Current input, connect to PIN diode anode 16 16 IN Input Current input, connect to PIN diode cathode REV KY.1.0.4 3 www.trusignal.com TS9517 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 Supply voltage VDD Supply voltage 1 PVDD LED driver supply voltage IDD Supply current PRF Pulse repetition frequency VDD=5.5V 1.25 I-F Transimpedance Amplifier fO Output frequency IIN=1uA Full-scale frequency 500 Nonlinearity Re 100 fO =0KHz to 10KHz 100 kHz/A 0.3 %/V 0.8 %/V 5 10 A 170 200 mA 7 Bits cancellation, f=100KHz With ambient light cancellation, f=100KHz IC Maximum ambient light cancellation current kHz %FS Current responsivity Power-supply rejection ratio 1000 ±1% Without ambient light PSRR kHz Transmitter 1 Full-scale output current TA=25°C VDD=5V, RPROG=4Ω Output current resolution Output current offset 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 Minimum on time of RED-LED 1.25 mA VDD=5V,RPROG=4Ω and IR-LED LED current pulses DAC linearity Percent of full-scale current 1% Output current settling time From zero current to 50 mA TBD µs (with resistive load) From 50 mA to zero current TBD µs 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 TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 Overview The TS9517 is a complete analog front-end (AFE) current is controlled by logic signals at the input pins circuit targeting pulse oximeter applications. The of RED_CS and IR_CS, both of which are active ‘high’ device consists of a low-noise I/F converter and a LED and each LED current can be adjusted by a 7-bit DAC transmitter section. The I/F converter converts the which can be programed by the SPI interface. An photodiode current to frequency signal precisely. The external resistor RPROG at the PROG pin sets the ratio output of the device connects directly to a high of the LED current to the input of the DAC, the resolution timer of the external microcontroller (MCU) maximum output current is primarily dependent on for which an A/D converter is not necessary. The LED RPROG, the power supply voltage PVDD, and the transmitter current can be programmed through the forward voltage of the LEDs. SPI™ interface. Receiver The receiver consists of a high precision current-to-frequency (I-F) converter section and an ambient light cancellation (ALC) circuitry. The I/F converter converts the photodiode current to frequency signal with high dynamic range and linearity. The ALC function can be enabled or disabled by the COE pin. When COE pin is set low, the ALC function is disabled; the converter continuously converts input Figure 1. Timing of LED Control and ALC. current to frequency without being interrupted by the LED control signals. In this mode, currents from both LED Current Control the ambient light and the signal light are converted at The output currents of the transmitter are controlled by the same time. When COE pin is set high or floating, the internal 7-bit DAC. The currents cover the range of the ALC function is enabled, the operation of the I/F 0 ~ 200mA and are given by the following equation: converter is in synchronization with the LED control 𝐼𝐿𝐸𝐷 = signals. When none of the LEDs are turned on, the 𝑁 × 𝑉𝐿𝑆𝐵 𝑅𝑃𝑅𝑂𝐺 receiver is in ambient light measurement mode in where N is the input of the DAC with a range from 0 ~ which the I/F converter stops operation; when one of 127, which can be programed by the SPI interface conversion mode and the I/F converter resume (see SPI interface); VLSB is the output of the DAC operation in which only the current from the signal corresponding to the LSB of the input which is about 8 light is converted. mV; RPROG is the resistance of RPROG which is user selectable. Transmitter Section The transmitter section integrates a programmable Timing Diagram of the Transmitter constant current source, an H-bridge LED driver and Figure 1 shows the timing diagram for the LED its control logic. Two LED driver schemes are transmitter control. Through the internal logic, signals supported: an H-bridge driver for a two-terminal at the RED_CS and IR_CS pins control the switches device with two reverse-paralleled LEDs, or two of the H-Bridge. In T1 and T3 cycles, both LEDs are push-pull drivers for a three-terminal device with two turned off (ALC mode). In T2 and T4 cycles, RED LED LEDs packaged together. The on-off of the LED and IR LED are turned on respectively (conversion REV KY.1.0.4 5 www.trusignal.com TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 mode). It should be noted that, however, when both the SPI interface and the registers store the input data signals at the pins of RED_CS and IR_CS are high at for RED and IR LED currents accordingly. Figure 2 the same time, there will be no current flowing through shows the timing of the SPI, where D7 is the first bit the two-terminal back-to-back packaged LEDs (see and D0 is the last bit (address bit). When CS is low, Table 2 and Table 3). the SPI interface is enabled, each bit is received at the rising edge of CLK. At the rising edge of CS, the data SPI interface and internal register is latched to one of the registers pointed by bit D0 and TS9517 integrates an 8-bit serial latch and two 8-bit the corresponding transmitter current is refreshed. registers. The latch takes the serial input data through The description of the registers is shown in Table 4. 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 Table 4. LEDCUR: LED Current Register and Latch D7 D6 D5 D4 D3 LEDCUR[7:1] D2 D1 D0 ADDR Figure 2. SPI timing diagram REV KY.1.0.4 6 www.trusignal.com TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 Application Examples Figure 3 and Figure 4 show typical applications of TS9517 as analog front-end for pulse oximeters. Please note that the pins of 11 and 12 and pins of 13 and 14 are interchanged between the two packages. VDD=2.5V~5.5V 2 C1 0.1uF 3 4 MCU 5 6 8 9 PVDD OUT CS U2 IN ANOD SDI IR CLK RED_CS RED IR_CS COE CAP PROG GND 1 VDD U1 13 14 PVDD=2.5V~5.5V 16 15 C3 C2 12 100uF 0.1uF 15 C3 C2 11 100uF 0.1uF 11 10 RPROG 7 C4 4Ω 0.1uF Figure 3. Typical Application of TS9517 in TSSOP16 Package VDD=2.5V~5.5V 2 C1 0.1uF 3 4 MCU 5 6 8 9 PVDD OUT CS U2 IN ANOD SDI IR CLK RED_CS IR_CS COE CAP RED GND 1 VDD U1 14 13 PVDD=2.5V~5.5V PROG 16 12 10 7 C4 RPROG 4Ω 0.1uF Figure 4. Typical Application of TS9517 in QFN16 Package REV KY.1.0.4 7 www.trusignal.com TS9517 Trusignal Microelectronics APRIL 2014 – REVISED AUGUST 2014 Mechanical Dimensions TSSOP-16 PACKAGE MECHANICAL DRAWING θ TSSOP-16 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 TS9517 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 TS9517 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 0512-65923982 Fax: +86 0512-65923995 REV KY.1.0.4 10 www.trusignal.com