Part No. Internal Clock VDD System
Clock
Program Memory Data Memory I/O

Timer

Interrupt A/D PWM PFD OPA SPI/
I2C
Stack Package
8-bit 16-bit Ext. Int.
HT45R52 4MHz
8MHz
12MHz
2.2V~
5.5V
400kHz~
12MHz or
32768Hz
2Kx15 192x8 18 1 -- 2 5 12-bitx12 12-bitx2 v 1 1 4 16DIP/NSOP, 20DIP/SSOP

HT45R54

4MHz
8MHz
12MHz
2.2V~
5.5V
400kHz~
12MHz or
32768Hz
4Kx15 384x8 30 1 1 2 6 12-bitx24 12-bitx4 v 1 1 8 20DIP/SSOP, 24/28SKDIP, 24/28SSOP, 32QFN

Note: These devices are only available in OTP versions.