ISL98012IUZ Intersil, ISL98012IUZ Datasheet - Page 7

• Manufacturer Part Number: ISL98012IUZ
• Description: IC BOOST ADJ .6A 10MSOP
• Manufacturer: Intersil
• Type: Step-Up (Boost)r

Specifications of ISL98012IUZ

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 4.5 ~ 17 V
• Current - Output: 600mA
• Frequency - Switching: 670kHz
• Voltage - Input: 1.8 ~ 13.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

Typical Performance Curves
Applications Information
The ISL98012 is a fixed frequency step-up pulse-width
modulation (PWM) regulator. The input voltage range is 1.8V
to 13.2V and output voltage range is 4.5V to 17V. The
switching frequency (up to 750kHz) is decided by the
resistor connected to RT pin.
Start-Up
During start-up, as V
start-up oscillator generates a fixed duty-ratio of 0.5 to 0.7 at
a frequency of several hundred kHz. This will boost the
output voltage.
When V
over control. The duty ratio will be decided by the least of the
multiple-input direct summing comparator, the Max_Duty
signal (about 92% duty-ratio), or the Current Limit
Comparator.
FIGURE 15. OUTPUT RIPPLE, V
FIGURE 13. LOAD TRANSIENT RESPONSE 10mA TO 30mA,
10mV/DIV
DD
reaches about 3.7V, the PWM comparator takes
OUTPUT LOAD CURRENT
V
I
O
IN
= 10mA TO 30mA
= 1.8V, FREQ = 56.2k, V
DD
reaches a threshold of about 1.6V, a
7
IN
= 1.8V, V
O
= 15V,
O
(Continued)
= 15V, I
O
= 30mA
ISL98012
Soft-start is provided by ramping up the current limit
comparator. An internal 12µA current source charges the
external CSS capacitor. The peak MOSFET current is limited
by the voltage on this capacitor. This in turn controls the
rising rate of the output voltage.
The regulator goes through the same start-up sequence as
well after the EN signal is pulled to HI.
Steady-State Operation
When the output reaches the preset voltage, the regulator
operates in steady state. Depending on the input/output
conditions and component values, the inductor operates in
either continuous-conduction mode or discontinuous-conduction
mode.
In continuous-conduction mode, inductor current is a
triangular waveform and LX voltage a pulse waveform. In
discontinuous-conduction mode, inductor current has
FIGURE 16. OUTPUT RIPPLE, V
ΔV
FIGURE 14. LOAD TRANSIENT RESPONSE, V
I
O
O
10mV/DIV
V
O
= 12V, I
0.2ms/DIV
O
= 50mA TO 300mA
IN
= 3.3V, V
O
= 15V, I
IN
= 5V,
December 8, 2010
O
100mA/DIV
0.5V/DIV
= 30mA
FN6654.1