Application Circuits
Typical Application Circuits
Application Circuit (WHRM + WSPO2)
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Hardware Power Reset (Active-Low) Input. The device remains in reset while this pin is in its active state. When the pin transitions to its inactive state, the device performs a POR reset (resetting all logic on all supplies except for real-time clock circuitry) and begins execution. This pin is internally connected with an internal pullup to the VDD supply as indicated in the Electrical Characteristics table. This pin should be left unconnected if the system design does not provide a reset signal to the device.
RSTN
RSTN
LED Output Driver 1. Connect the LED cathode to LED1_DRV and its anode to the VLED supply.
LED1_DRV
LED1_DRV
LED Output Driver 2. Connect the LED cathode to LED2_DRV and its anode to the VLED supply.
LED2_DRV
LED2_DRV
LED Output Driver 3. Connect the LED cathode to LED3_DRV and its anode to the VLED supply.
LED3_DRV
LED3_DRV
PO8 (SCL)
(SCL) P0.8
PO9 (SDA)
(SDA) P0.9
Photodiode Cathode Input (CH2)
PD_IN2
PD2_IN
Cathode of Photodiode2 (PD2)
PD_CAT
PD2_CAT
PO12
HOST
PROCESSOR
GPIO1
SCL
GPIO1
SDA
GPIO1
RESET
PO12
ACCELEROMETER
(
KIONIX
KX
122
)
SCLK
SCLK
SDI
SDI
SDO
SDO
CSB
CS
CSB
INT
AFE Power Supply Return. Connect to GND.
SDO
GND
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
SDO
V
DD
GPIO1
+1.8V
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
GPIO1
V
DD
GPIO1
INT
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
SDO
V
DD
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
GPIO1
V
DD
AFE Power Supply Return. Connect to GND.
SDO
GND
GPIO1
+1.8V
Photodiode Cathode Input (CH1)
PD_IN1
PD1_IN
PO.4 (MISO)
(MISO) P0.4
PO.5 (MOSI)
(MOSI) P0.5
PO.6 (SCLK)
(SCK) P0.6
PO.3
(PPG_INT) P0.3
PO.2 (INTB)
(ACCEL_INT) P0.2
PO.1(SWDCLK)
(MFIO) P0.1
PO.0(SWDIO)
(ACCEL_CS) P0.0
32.768kHz Crystal Oscillator Input. Connect a 6pF 32.768kHz watch crystal, CL = 6pF, ESR < 90kΩ, C0 < 2pF crystal between 32KIN and 32KOUT for normal operation. Optionally, an external clock source can be driven on 32KIN if the 32KOUT pin is left unconnected.
32KIN
32KIN
32.768kHz Crystal Oscillator Output. Connect a 6pF 32.768kHz watch crystal, CL = 6pF, ESR < 90kΩ, C0 < 2pF crystal between 32KIN and 32KOUT for normal operation. Optionally, an external clock source can be driven on 32KIN if the 32KOUT pin is left unconnected.
32KOUT
32KOUT
PO8 (SCL)
32.768KHz
(
6pF)
Not Connected. Connect to unconnected PCB pad for mechanical stability. N.C. pins should not be connected to any signal, power, or ground pins.
N.C.
N.C.
PD_CAT
MAX14689
RSTN
GREEN1
RSTN
IR
RSTN
GREEN2
RSTN
RED
RSTN
COM1
RSTN
COM2
RSTN
NO2
RSTN
NC2
RSTN
NO1
RSTN
NC1
General Purpose I/O. Open-drain when programmed as output (active low). Drives Select pin on (optional) External LED MUX. If external LED MUX is not used, set as N.C.
GPIO1
AFE_GPIO1
RSTN
CB
PD_GND
100kΩ
PD_GND
SHORT
LED Power Return. Connect to PGND.
PD_CAT
PGND
AFE Power Supply Return. Connect to GND.
PD_CAT
GND
RSTN
FIREFLY
EE
2218
RSTN
GREEN1
PD_GND
22µF
PD_GND
+5.0V
PD_GND
22µF
AFE Power Supply Return. Connect to GND.
GND_DIG
GND
Photodiodes Anode. Connect to GND.
PD_IN1
PD_GND
LED Power Return. Connect to PGND.
PGND
PGND
MCU Digital Ground. Connect to GND.
VSS
V
SS
Internal reference decoupling point. Bypass with a 1.0μF capacitor to GND.
REF
VREF
PD_GND
1µF
PD_CAT
SFH7015
RSTN
IR
RSTN
RED
PD_GND
22µF
PD_GND
22µF
PD_GND
+5.0V
LED Power Supply Input. Connect to an external voltage supply. Bypass with a 10μF and 0.1μF capacitor to PGND.
VLED
V
LED
PD_GND
22µF
PD_GND
+5.0V
MCU Core Supply Voltage. This pin provides dual supply operation to support PMIC-based systems and should be left open-circuit for single supply operation. This pin must always be bypassed to VSS with a 1.0μF capacitor as close as possible to the package regardless of the supply mode of operation.
VCORE
V
CORE
PD_GND
1µF
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
VDD
V
DD
PD_GND
1µF
PD_GND
+1.8V
PD_GND
0.1µF
PD_GND
10µF
PD_GND
+1.8V
AFE Power Supply Input. Connect to an externally-regulated supply. Bypass with a 0.1μF capacitor as close as possible to pad and a 10μF capacitor to GND.
VDD_ANA
V
DD
_
AFE
SCLK CKPOL/CKPHA 0/0 OR 1/1
MAXM86146
RSTN
GREEN2
RSTN
FIREFLY
EE
2218
PD_GND
22µF
PD_GND
22µF
PD_GND
+5.0V
PD_GND
100nF
PD_GND
10
W
RSTN
NOISE
SNUBBER
PD_GND
4.7kΩ
PD_GND
4.7kΩ
PD_GND
4.7kΩ
Application Circuit 2 (WHRM)
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Hardware Power Reset (Active-Low) Input. The device remains in reset while this pin is in its active state. When the pin transitions to its inactive state, the device performs a POR reset (resetting all logic on all supplies except for real-time clock circuitry) and begins execution. This pin is internally connected with an internal pullup to the VDD supply as indicated in the Electrical Characteristics table. This pin should be left unconnected if the system design does not provide a reset signal to the device.
RSTN
RSTN
LED Output Driver 1. Connect the LED cathode to LED1_DRV and its anode to the VLED supply.
LED1_DRV
LED1_DRV
LED Output Driver 2. Connect the LED cathode to LED2_DRV and its anode to the VLED supply.
LED2_DRV
LED2_DRV
LED Output Driver 3. Connect the LED cathode to LED3_DRV and its anode to the VLED supply.
LED3_DRV
LED3_DRV
PO8 (SCL)
(SCL) P0.8
PO9 (SDA)
(SDA) P0.9
Photodiode Cathode Input (CH2)
PD_IN2
PD2_IN
Cathode of Photodiode2 (PD2)
PD_CAT
PD2_CAT
PO12
HOST
PROCESSOR
GPIO1
SCL
GPIO1
SDA
GPIO1
RESET
PO12
ACCELEROMETER
(
KIONIX
KX
122
)
SCLK
SCLK
SDI
SDI
SDO
SDO
CSB
CS
CSB
INT
AFE Power Supply Return. Connect to GND.
SDO
GND
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
SDO
V
DD
GPIO1
+1.8V
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
GPIO1
V
DD
GPIO1
INT
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
SDO
V
DD
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
GPIO1
V
DD
AFE Power Supply Return. Connect to GND.
SDO
GND
PD_GND
4.7kΩ
GPIO1
+1.8V
Photodiode Cathode Input (CH1)
PD_IN1
PD1_IN
PO.4 (MISO)
(MISO) P0.4
PO.5 (MOSI)
(MOSI) P0.5
PO.6 (SCLK)
(SCK) P0.6
PO.3
(PPG_INT) P0.3
PO.2 (INTB)
(ACCEL_INT) P0.2
PO.1(SWDCLK)
(MFIO) P0.1
PO.0(SWDIO)
(ACCEL_CS) P0.0
32.768kHz Crystal Oscillator Input. Connect a 6pF 32.768kHz watch crystal, CL = 6pF, ESR < 90kΩ, C0 < 2pF crystal between 32KIN and 32KOUT for normal operation. Optionally, an external clock source can be driven on 32KIN if the 32KOUT pin is left unconnected.
32KIN
32KIN
32.768kHz Crystal Oscillator Output. Connect a 6pF 32.768kHz watch crystal, CL = 6pF, ESR < 90kΩ, C0 < 2pF crystal between 32KIN and 32KOUT for normal operation. Optionally, an external clock source can be driven on 32KIN if the 32KOUT pin is left unconnected.
32KOUT
32KOUT
PO8 (SCL)
32.768KHz
(
6pF)
General Purpose I/O. Open-drain when programmed as output (active low). Drives Select pin on (optional) External LED MUX. If external LED MUX is not used, set as N.C.
GPIO1
AFE_GPIO1
LED Power Return. Connect to PGND.
PD_CAT
PGND
AFE Power Supply Return. Connect to GND.
PD_CAT
GND
AFE Power Supply Return. Connect to GND.
GND_DIG
GND
Photodiodes Anode. Connect to GND.
PD_IN1
PD_GND
LED Power Return. Connect to PGND.
PGND
PGND
MCU Digital Ground. Connect to GND.
VSS
V
SS
Internal reference decoupling point. Bypass with a 1.0μF capacitor to GND.
REF
VREF
PD_GND
1µF
LED Power Supply Input. Connect to an external voltage supply. Bypass with a 10μF and 0.1μF capacitor to PGND.
VLED
V
LED
PD_GND
22µF
PD_GND
+5.0V
MCU Core Supply Voltage. This pin provides dual supply operation to support PMIC-based systems and should be left open-circuit for single supply operation. This pin must always be bypassed to VSS with a 1.0μF capacitor as close as possible to the package regardless of the supply mode of operation.
VCORE
V
CORE
PD_GND
1µF
MCU Digital Supply Voltage. This pin must be bypassed to VSS with a 1.0μF capacitor as close as possible to the package. The device can operate solely from this one power supply pin without the need to connect VCORE by utilizing the internal VCORE regulator. The internal VCORE regulator automatically operates if the presence of a voltage on the VCORE pin is not detected. This provides single-supply-battery operation capability.
VDD
V
DD
PD_GND
1µF
PD_GND
+1.8V
PD_GND
0.1µF
PD_GND
10µF
PD_GND
+1.8V
AFE Power Supply Input. Connect to an externally-regulated supply. Bypass with a 0.1μF capacitor as close as possible to pad and a 10μF capacitor to GND.
VDD_ANA
V
DD
_
AFE
SCLK CKPOL/CKPHA 0/0 OR 1/1
MAXM86146
Not Connected. Connect to unconnected PCB pad for mechanical stability. N.C. pins should not be connected to any signal, power, or ground pins.
N.C.
N.C.
Not Connected. Connect to unconnected PCB pad for mechanical stability. N.C. pins should not be connected to any signal, power, or ground pins.
N.C.
N.C.
RSTN
GREEN1
PD_GND
22µF
PD_GND
+5.0V
PD_GND
22µF
RSTN
FIREFLY
EE
2218
PD_GND
SHORT
PD_GND
EXTERNAL
PHOTODIODE
VEMD
8080
PD_GND
100nF
PD_GND
10Ω
RSTN
NOISE
SNUBBER
Not Connected. Connect to unconnected PCB pad for mechanical stability. N.C. pins should not be connected to any signal, power, or ground pins.
N.C.
N.C.
PD_GND
4.7kΩ
PD_GND
4.7kΩ
