Datasheet

0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
5 10 15 20 25 30 35 40
Input Voltage (V)
Output Current (A)
V
O
= –3.3 V
V
O
= –5 V
V
O
= –12 V
V
O
= –15 V
G000
( )
OUT
SET
V
R 10 1 k
0.798
æ ö
= ´ - W
ç ÷
ç ÷
è ø
LMZ34002
SNVS989A –JULY 2013–REVISED SEPT 2013 www.ti.com
APPLICATION INFORMATION
Adjusting the Output Voltage
The LMZ34002 is designed to provide output voltages from –3 V to –17 V. The output voltage is determined by
the value of R
SET
, which must be connected between the VADJ pin (Pin 36) and GND. Table 2 gives the
standard external R
SET
resistor for a number of common bus voltages.
Table 2. Standard R
SET
Resistor Values for Common Output Voltages
OUTPUT VOLTAGE V
OUT
(V) –3.3 –5.0 –8.0 –12.0 –15.0
R
SET
(kΩ) 31.6 52.3 90.9 140 178
For other output voltages the value of R
SET
can be calculated using the following formula, or simply selected from
the range of values given in Table 3.
(1)
Table 3. Standard R
SET
Resistor Values
V
OUT
(V) R
SET
(kΩ) V
OUT
(V) R
SET
(kΩ) V
OUT
(V) R
SET
(kΩ)
–3.0 27.4 –7.5 84.5 –12.5 147
–3.3 31.6 –8.0 90.9 –13.0 154
–3.5 34.0 –8.5 97.6 –13.5 158
–4.0 40.2 –9.0 102 –14.0 165
–4.5 46.4 –9.5 110 –14.5 174
–5.0 52.3 –10.0 115 –15.0 178
–5.5 59.0 –10.5 121 –15.5 187
–6.0 64.9 –11.0 127 –16.0 191
–6.5 71.5 –11.5 133 –16.5 196
–7.0 78.7 –12.0 140 –17.0 205
Safe Operating Current
The amount of output current that can safely be delivered by the LMZ34002 depends on the input voltage and
the output voltage. Figure 33 shows the maximum output current for four standard output voltages over input
voltage.
Figure 33. Safe Operating Current
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