M02061 Datasheet, PDF (28/37 Pages) M/A-COM Technology Solutions, Inc. – 3.3 or 5 Volt Laser Driver

Functional Description
3.3.8
TX Disable and Disable Delay Control
The DIS pin is used to disable the transmit signal (both the modulation and bias current are disabled when DIS =
high).
The DIS input is compatible with TTL levels regardless of whether VCC = 5V or VCC = 3.3V. The external 4.7kΩ
and 10kΩ pull-up resistor required by most interface standards is not needed because this pin has an internal 7kΩ
resistor to V_CC.
The DISDLY pin is used in conjunction with the DIS pin to control bias current enable time. In normal operation the
DISDLY pin should be connected to ground. In this case, each time DIS transitions from high to low the bias current
will be enabled by the “slow-start” circuitry (enable time of less than 1 ms with a C_APC = 2.2 nF).
For burst mode operation a capacitor C is added to the DISDLY pin, the slow-start circuitry is disabled for
approximately T = 3 * 10⁶ (sec/F) * C (F) following the DIS high transition (see figure 8). If the part is enabled (DIS
transitions low) during this time the bias and modulation current will quickly return to within 90% of their final value
(in less than 500ns). If DIS transitions low after the DISDLY time the slow-start circuitry will engage and the bias
current will not return to its final value for approximately 1ms (depending on the C_APC capacitor value).
02061-DSH-001-G
Mindspeed Technologies^®
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