MAX14890E Datasheet, PDF (1/30 Pages) Maxim Integrated Products – Overvoltage and Undervoltage Fault Detection

MAX14890E
Incremental Encoder Interface for RS-422,
HTL, and TTL with Digital Inputs
General Description
The MAX14890E incremental encoder receiver contains
four differential receivers and two single-ended receivers.
The differential receivers can be operated in RS-422 or
differential high-threshold logic (HTL) modes and are
optionally configurable for single-ended TTL/HTL operation.
The MAX14890E features a wide common mode input
range of -20V to +20V in RS-422 mode.
The auxiliary IEC 61131-2 Type-1/Type-3 digital inputs
are designed for operation with switches or proximity
sensors and can be individually configured for TTL operation.
All receiver input signals are fault protected to voltage shorts
in the ±40V range. Per channel fault detection provides
warning of irregular conditions such as small differential
signals, shorts, opens, overvoltages, and undervoltages.
The MAX14890E features a pin-selectable SPI or parallel-
logic interface. SPI control provides detailed diagnostics
and individual configurations for receivers.
The MAX14890E is available in a 32-pin TQFN-EP (5mm
x 5mm) and operates over the -40°C to +125°C tempera-
ture range.
Ordering Information appears at end of data sheet.
Typical Operating Circuit
ENCODER
RS-422 A
RS-422 B
RS-422 Z
TTL ALARM
PROXIMITY ^DO
SENSOR
PROXIMITY ^DO
SENSOR
120Ω
120Ω
120Ω
5V
VCC
A
RxA
A
B
RxB
B
Z
RxZ
Z
DIY
RxY
DI2 _RxD2
VL
AO
AFAULT
BO
BFAULT
ZO
ZFAULT
YO
YFAULT
LO2
3.3V to 5V
5V
5V
5V
5V
DI3 _RxD3
LO3
MAX14890
SNGL/CLK = 0
TTL/SDI = 1
DI/TTLY = 1
DI/TTL2 = 1
DI/TTL3 = 1
ASIC
COUNTER/
MOTOR
CONTROLLER
ENCODER CIRCUIT WITH RS-422 SIGNALS AND TTL ALARM SIGNAL
Benefits and Features
●● High Flexibility Supports All Encoder Types
• Selectable RS-422/HTL/TTL/DI Receivers
• RS-422/TTL Switching Rates Up to 35Mbps
• HTL Switching Rates Up to 400kHz
• SPI or Pin-Controlled Operation
• SPI Interface Allows Per-Receiver Configuration
• 1.62V to 5.5V Logic Interface
●● Integrated Fault Detection Reduces Down-Time
• Open-Wire and Short-Circuit Detection
• Overvoltage and Undervoltage Fault Detection
●● Integrated Protection Ensures Robust
Communication
• ±40V Fault Protection Range
• ±20V RS-422 Common Mode Range
• DI Glitch Filters
• ±25kV HBM ESD
• ±7kV Air-Gap per IEC 61000-4-2 ESD
• ±10kV Contact per IEC 61000-4-2 ESD
• -40°C to +125°C Operating Temperature Range
Applications
●● Encoder Interfaces
●● Motor Controllers
●● Pulse Counters
●● Servo Control Commutation
Input Receiver Modes
MODE RxA RxB RxZ RxY RxDI2 RxDI3
RS-422
√
√
√
√
D-HTL
√
√
√
SE-HTL
√
√
√
TTL
√
√
√
√
√
√
DI
√
√
√
√
19-7536; Rev 0; 3/15