ISL6522_06 Datasheet, PDF (5/15 Pages) Intersil Corporation – Buck and Synchronous Rectifier Pulse-Width Modulator (PWM) Controller

ISL6522
Electrical Specifications Recommended Operating Conditions, Unless Otherwise Noted (Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
Upper Gate Sink
Lower Gate Source
Lower Gate Sink
PROTECTION
R_UGATE
I_LGATE
R_LGATE
ISL6522C, I_LGATE = 0.3A
ISL6522I, I_LGATE = 0.3A
V_CC = 12V, V_LGATE = 6V
ISL6522C, I_LGATE = 0.3A
ISL6522I, I_LGATE = 0.3A
-
5.5
-
5.5
300
450
-
3.5
-
3.5
OCSET Current Source
Soft-Start Current
I_OCSET
I_SS
V_OCSET = 4.5VDC
170
200
-
10
MAX
10
7.2
-
6.5
4.5
230
-
UNITS
Ω
Ω
mA
Ω
Ω
µA
µA
Typical Performance Curves
1000
100
10
R_T PULLUP
TO +12V
R_T PULLDOWN
TO V_SS
10
100
SWITCHING FREQUENCY (kHz)
FIGURE 1. R_T RESISTANCE vs FREQUENCY
1000
80
70
60
C_GATE = 3300pF
50
40
30
C_GATE = 1000pF
20
10
C_GATE = 10pF
0
100 200 300 400 500 600 700 800 900 1000
SWITCHING FREQUENCY (kHz)
FIGURE 2. BIAS SUPPLY CURRENT vs FREQUENCY
Functional Pin Descriptions
SOIC
and
TSSOP
RT 1
OCSET 2
SS 3
COMP 4
FB 5
EN 6
GND 7
14 _VCC
13 PVCC
12 LGATE
11 PGND
10 BOOT
9 UGATE
8 PHASE
QFN
16 15 14 13
SS 1
COMP 2
FB 3
EN 4
GND
12 PVCC
11 LGATE
10 PGND
9 BOOT
5678
RT
This pin provides oscillator switching frequency adjustment.
By placing a resistor (R_T) from this pin to GND, the nominal
200kHz switching frequency is increased according to the
following equation:
Fs ≈ 200kHz + ⁵-----^•-----¹---⁰----⁶-
R_T
(R_T to GND)
Conversely, connecting a pull-up resistor (R_T) from this pin
to V_CC reduces the switching frequency according to the
following equation:
Fs ≈ 200kHz – ⁴-----^•-----¹---⁰----⁷-
R_T
(R_T to 12V)
5
FN9030.8
March 10, 2006