Functional Diagram
Functional Diagrams
MAX14914 and MAX14914A
Current Limiter
CURRENT
LIMITER
Output Drive
OUTPUT
DRIVE
Switch Control Input. Drive IN high to close the HS switch; drive IN low to open the HS switch and close the LS switch (when PP = low).
IN
IN
Digital Input Mode Logic Enable Input. Set DI_EN high to enable digital input operation on the DOI pin, which enables the internal current sink and sets Type 1, Type 2, or Type 3 thresholds on DOI_LVL. Select between Type 1 and 3, and Type 2 DI characteristics through the PP input.
DI_EN
DI_EN
Push-Pull DO or DI Type Select Input. In DO mode, set PP high to enable push-pull mode operation of the DO driver. In DI mode, set PP low for IEC Type 1/3 input characteristics and set high for Type 2 input characteristics.
PP
PP
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
Supply Voltage, Nominally 24V. Bypass VDD to GND through a 1uF capacitor.
VDD
VDD
Power Ground
PGND
PGND
Analog Ground
GND
GND
5V Regulator
5V REGULATOR
5V Regulator Input. Connect REGIN to VDD when using the internal 5V regulator. Connect REGIN to V5 when powering V5 from an external regulator.
REGIN
REGIN
Analog Supply Voltage/LDO Output. The MAX14914 requires a 5V supply for normal operation, which can come from the internal linear regulator (REGIN connected to VDD) or from an external regulator (REGIN connected to V5). Bypass to GND through a 1μF ceramic capacitor.
V5
V5
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
VTH
VTH
Open-Drain Overvoltage Output for the MAX14914 and MAX14914A. The OV_VDD transistor turns off when: 1) a device configured for DI operation; 2) DOI level is higher than VDD. Connect a pullup to VDD.
OV_VDD
OV_VDD
Analog Ground
GND
GND
Analog Ground
GND
GND
Output Mode
OUTPUT
MODE
Control Logic
CONTROL LOGIC
Logic Supply Input. VL defines the levels on all I/O logic interface pins. Bypass VL to GND through a 100nF ceramic capacitor.
VL
VL
Interface Logic Supply
INTERFACE
LOGIC SUPPLY
Open-Drain Fault Output. The FAULT transistor turns on when a fault condition (driver thermal shutdown or loss of ground) occurs. Connect a pullup to VL or V5.
FAULT
FAULT
Open-Drain DOI Level Output. DOI_LVL is logic-low when DOI voltage is higher than the threshold voltage. DOI_LVL is logic-high (using a pullup resistor) when DOI voltage is lower than the threshold voltage. The threshold voltage depends on DI_EN. Connect a pullup to VL or V5.
DOI_LVL
DOI_LVL
DI Sink Current
DI SINK
CURRENT
Analog Ground
GND
GND
Analog Ground
GND
GND
CLIM
CLIM
Digital Input Mode Logic Enable Input. Set DI_EN high to enable digital input operation on the DOI pin, which enables the internal current sink and sets Type 1, Type 2, or Type 3 thresholds on DOI_LVL. Select between Type 1 and 3, and Type 2 DI characteristics through the PP input.
DI_EN
DI_EN
Thermal Shutdown Protection
THERMAL
SHUTDOWN
PROTECTION
5V Supply to Analog Section
5V SUPPLY TO
ANALOG SECTION
MAX14914B
Current Limiter
CURRENT
LIMITER
Output Drive
OUTPUT
DRIVE
Switch Control Input. Drive IN high to close the HS switch; drive IN low to open the HS switch and close the LS switch (when PP = low).
IN
IN
Digital Input Mode Logic Enable Input. Set DI_EN high to enable digital input operation on the DOI pin, which enables the internal current sink and sets Type 1, Type 2, or Type 3 thresholds on DOI_LVL. Select between Type 1 and 3, and Type 2 DI characteristics through the PP input.
DI_EN
DI_EN
Push-Pull DO or DI Type Select Input. In DO mode, set PP high to enable push-pull mode operation of the DO driver. In DI mode, set PP low for IEC Type 1/3 input characteristics and set high for Type 2 input characteristics.
PP
PP
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
Supply Voltage, Nominally 24V. Bypass VDD to GND through a 1uF capacitor.
VDD
VDD
Power Ground
PGND
PGND
Analog Ground
GND
GND
5V Regulator
5V REGULATOR
5V Regulator Input. Connect REGIN to VDD when using the internal 5V regulator. Connect REGIN to V5 when powering V5 from an external regulator.
REGIN
REGIN
Analog Supply Voltage/LDO Output. The MAX14914 requires a 5V supply for normal operation, which can come from the internal linear regulator (REGIN connected to VDD) or from an external regulator (REGIN connected to V5). Bypass to GND through a 1μF ceramic capacitor.
V5
V5
High-Side / Push-Pull Output (DI_EN = low) or Digital Input (DI_EN = high). Connect both DOI pins together externally.
DOI
DOI
VTH
VTH
Open-Drain Overcurrent Output for the MAX14914B. OV_CURR turns active low when the load current exceeds the high-side current limit. Connect a pullup resistor between OV_CURR and VL.
OV_CURR
OV_CURR
Analog Ground
GND
GND
Analog Ground
GND
GND
Output Mode
OUTPUT
MODE
Control Logic
CONTROL LOGIC
Logic Supply Input. VL defines the levels on all I/O logic interface pins. Bypass VL to GND through a 100nF ceramic capacitor.
VL
VL
Interface Logic Supply
INTERFACE
LOGIC SUPPLY
Open-Drain Fault Output. The FAULT transistor turns on when a fault condition (driver thermal shutdown or loss of ground) occurs. Connect a pullup to VL or V5.
FAULT
FAULT
Open-Drain DOI Level Output. DOI_LVL is logic-low when DOI voltage is higher than the threshold voltage. DOI_LVL is logic-high (using a pullup resistor) when DOI voltage is lower than the threshold voltage. The threshold voltage depends on DI_EN. Connect a pullup to VL or V5.
DOI_LVL
DOI_LVL
DI Sink Current
DI SINK
CURRENT
Analog Ground
GND
GND
Analog Ground
GND
GND
CLIM
CLIM
Thermal Shutdown Protection
THERMAL
SHUTDOWN
PROTECTION
5V Supply to Analog Section
5V SUPPLY TO
ANALOG SECTION
