HCS370

Features:

Security
• Two programmable 32-bit serial numbers
• Two programmable 64-bit encoder keys
• Two programmable 60-bit seed values
• Each transmission is unique
• 67/69-bit transmission code length
• 32-bit hopping code
• Crypt keys are read protected
Operating
• 2.05-5.5V operation
• Six button inputs
• 15 functions available
• Four selectable baud rates
• Selectable minimum code word completion
• Battery low signal transmitted to receiver
• Nonvolatile synchronization data
• PWM, VPWM, PPM, and Manchester modulation
• Button queue information transmitted
• Dual Encoder functionality
Other
• On-chip EEPROM
• On-chip tuned oscillator (±10% over voltage and temperature)
• Button inputs have internal pull-down resistors
• LED output
• PLL control for ASK and FSK
• Low external component count
• Step-up voltage regulator




Application

The HCS370 is ideal for Remote Keyless Entry (RKE)
applications. These applications include:
• Automotive RKE systems
• Automotive alarm systems
• Automotive immobilizers
• Gate and garage door openers
• Identity tokens
• Burglar alarm systems




Pinout






Specifications

Parameter NameValueProtocols29Transmission Code Length Bits69Other FeaturesStep-up voltage regulation, Dual Encoder Operation, 6 inputs, Queue counterSeed Length 0Code Hoppings Bits32Operating Voltage (V)2.05 to 5.5Tunable OSCYesFunction Codes15CRCYes

Parameter Name	Value
Protocols	29
Transmission Code Length Bits	69
Other Features	Step-up voltage regulation, Dual Encoder Operation, 6 inputs, Queue counter
Seed Length	0
Code Hoppings Bits	32
Operating Voltage (V)	2.05 to 5.5
Tunable OSC	Yes
Function Codes	15
CRC	Yes

Ambient temperature under bias.....................................................-40°C to +125°C
Storage temperature ..................................................................... -65°C to +150°C
Voltage on V_DD w/respect to V_SS ........................................................... -0.3 to +7.5V
Voltage on L_ED w/respect to V_SS ..............................................................-0.3 to +11V
Voltage on all other pins w/respect to V_SS ....................................-0.3V to V_DD + 0.3V
Total power dissipation (Note 1) .....................................................................500 mW
Maximum current out of V_SS pin ........................................................................100 mA
Maximum current into V_DD pin ...........................................................................100 mA
Input clamp current, I_IK (V_I < 0 or V_I > V_DD) ...................................................± 20 mA
Output clamp current, IOK (Vo < 0 or Vo >V_DD)................................................± 20 mA
Maximum output current sunk by any Output pin.................................................25 mA
Maximum output current sourced by any Output pin ...........................................25 mA
*Notice: Stresses above those listed under "Maximum ratings" may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at those or any other conditions above those indicated in the
operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may
affect device reliability.
Note 1: Power dissipation is calculated as follows: Pdis=VDD x {IDD - Â IOH} + Â {(VDD-VOH) x IOH} + Â(VOl x IOL).




Description

The HCS370 is a code hopping encoder designed for secure Remote Keyless Entry (RKE) systems. It utilizes Microchip's patented KEELOQ? hopping technology, which incorporates high security, a small package outline, and low cost, to make this device a perfect solution for unidirectional remote keyless entry systems and access control systems. The HCS370 combines a 32-bit hopping code generated by a non-linear encryption algorithm, with a 28/32-bit serial number and 5/3 status bits to create a 69-bit transmission stream. The length of the transmission eliminates the threat of code scanning and the code hopping mechanism makes each transmission unique, thus rendering code capture and re-send (code grabbing) schemes useless. The encoder key, serial number, and configuration data are stored in EEPROM, which is not accessible via any external connection. This makes the HCS370 a very secure unit. The HCS370 provides an easy-to-use serial interface for programming the necessary security keys, system parameters, and configuration data. The HCS370 operates over a wide voltage range of 2.05V to 5.5V and has four button inputs in an 14-pin configuration. This allows the system designer the freedom to utilize up to 15 functions.