AD9660KR Analog Devices Inc, AD9660KR Datasheet - Page 5

• Manufacturer Part Number: AD9660KR
• Description: IC LASER DIODE DRIVER 28-SOIC
• Manufacturer: Analog Devices Inc
• Type: Laser Diode Driverr

Specifications of AD9660KR

• Number Of Channels: 1
• Rohs Status: RoHS non-compliant
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 110mA
• Current - Modulation: 60mA
• Current - Bias: 90mA
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Mounting Type: Surface Mount
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Mounting: Surface Mount
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Compliant

REV. 0
THEORY OF OPERATION
The AD9660 combines a very fast output current switch with
onboard analog light power control loops to provide the user
with a complete laser diode driver solution. The block diagram
illustrates the key internal functions. The control loops of the
AD9660, the bias loop and the write loop, adjust the output
current level, I
I
voltage at BIAS LEVEL or WRITE LEVEL. Since the monitor
MONITOR
C
Figure 1. Driving ML64116R Laser @ 30 mW
GAIN
–193.8mV
, out of SENSE IN is proportional to the analog input
AD9660
6.25mV
OUTPUT
OUT
WRITE LEVEL
OFFSET PULSE
MONITOR
R
POWER
BIAS LEVEL
WRITE PULSE
GAIN
WRITE HOLD
WRITE CAL
BIAS HOLD
, so that the photo diode feedback current,
BIAS CAL
DISABLE
ML64116R
20mV
GAIN
TTL
TTL
TTL
ANALOG
ANALOG
ANALOG
TTL
TTL
PHOTO DETECTOR
50
ANTEL
–120V
ARS1
50
DISABLE
2ns
CIRCUIT
DELAY
*
Figure 3. Functional Block Diagram
TEK 11802
O'SCOPE
50
5pF
Typical Performance Characteristics–AD9660
5pF
V
V
REF
REF
TZA
V:1
AD9660
–5–
V:1
V
2* I
REF
current is proportional to the laser diode light power, the loops
effectively control laser power to a level proportional to the ana-
log inputs. The control loops should be periodically calibrated
independently (see Choosing C
The offset current generator produces an open loop output cur-
rent, I
a current out DAC (see Figure 2). While I
brated as the currents from the bias and write loops are, it can
be very versatile (see Offset Current below).
MONITOR
OFFSET
1.85:1
1:10
1:10
1:10
35
30
25
20
15
10
5
0
0
I
. Its level is controlled by an external set resistor or
MODULATION
VOLT
REF
I
I
OFFSET
BIAS
Figure 2. I
5
1.4V
4.0V
V
OFFSET CURRENT
OUTPUT
SENSE IN
I
REF
MONITOR
I
OUT
OFFSET
10
R
OUT
OFFSET
BIAS HOLD
SET
vs. R
*
– k
10ns DELAY ON RISING
EDGE; 0ns ON FALLING
WRITE LOOP
15
PHOTO
DETECTOR
OFFSET
and C
BIAS LOOP
+V
OFFSET
S
LASER
DIODE
20
WRITE HOLD
is not cali-
25
).