Data Sheet
MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
3901090614 Page 18 of 52 Data Sheet
Rev 008 February 28, 2013
8.4.7 Timing specification
The MLX90614 meets all the timing specifications of the SMBus [1]. The maximum frequency of the
MLX90614 SMBus is 100 KHz and the minimum is 10 KHz.
The specific timings in MLX90614’s SMBus are:
SMBus Request (
) is the time that the SCL should be forced low in order to switch MLX90614 from
PWM mode to SMBus mode – at least 1.44ms;
Timeout L is the maximum allowed time for SCL to be low during communication. After this time the
MLX90614 will reset its communication block and will be ready for new communication – not more than 27ms;
Timeout H is the maximum allowed time for SCL to be high during communication.
After this time
MLX90614 will reset its communication block assuming that the bus is idle (according to the SMBus
specification) – not more than 45s.
Tsuac(SD)
is the time after the eighth falling edge of SCL that MLX90614 will force PWM / SDA low to
acknowledge the last received byte – not more than 2,5s.
Thdac(SD)
is the time after the ninth falling edge of SCL that MLX90614 will release the PWM / SDA
(so the MD can continue with the communication) – not more than 1,5s.
Tsuac(MD) is the time after the eighth falling edge of SCL that MLX90614 will release PWM / SDA (so
that the MD can acknowledge the last received byte) – not more than 1,5s.
Thdac(MD)
is the time after the ninth falling edge of SCL that MLX90614 will take control of the PWM /
SDA (so it can continue with the next byte to transmit) – not more than 1,5s.
The indexes MD and SD for the latest timings are used – MD when the master device is making
acknowledge; SD when the slave device is making acknowledge. For other timings see [1].
SCL
SDA
Timeout_L
> 27ms
Timeout_H
> 45µs
1 2 3 4 5 6 7 8 9
1 0 1 0 1 0 1 1 ACK
Tsuac Thdac
MD < 1.5µs
SD < 2.5µs
MD < 1.5µs
SD < 1.5µs
Figure 10: SMBus timing specification and definition