Product Specification
IXD3235/36/37
6) The CE/MODE pin of the IXD3237A series functions also as an external switching pin between PWM and PWM/PFM control. Control
is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than VIN minus 0.3 V,
and to the PWM mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0V. However, it should be equal to or
greater than VCEH
7) Time from moment when VOUT is shorted to GND via 1 Ω resistor to the moment, when Current Limit generates pulse stopping LX
oscillations
8) When VIN is less than 2.4 V, current limit may not be reached because of voltage drop across ON resistance
9) When the difference between input and output voltage is small, some cycles may be skipped completely before current maximizes. If
load current increases in this state, output voltage will decrease because of the voltage drop across P-channel transistor
10) Current limit denotes the level of an inductor peak current
11) Voltage, when LX pin voltage is “L”=+0.1 V ~ -0.1 V
12) Not for IXD3235 series, because they have PWM mode only
13) The IXD3237 series only
14) Voltage at which LX pin state changes from “L” to “H” = VIN ~ VIN - 1.2 V”
15) Voltage at which LX pin state changes from “H” to “L” ”=+0.1 V ~ -0.1 V
TABLE A
PFM Switching Current (IPFM) vs. Oscillation Frequency and Setting Voltage
fOSC = 1.2 MHz
fOSC = 3.0 MHz
SETTING VOLTAGE
MIN
140
130
120
TYP
180
170
160
MAX
240
220
200
MIN
190
180
170
TYP
260
240
220
MAX
350
300
270
VOUT(E) ≤ 1.2 V
1.2 V < VOUT(E) ≤ 1.75V
VOUT(E) ≥ 1.8 V
TABLE B
Input Voltage (VIN) for Measuring P-channel ON time maximum tPON_MAX
fOSC
1,2 MHZ
3 MHZ
VIN
VOUT(E) + 0.5 V
VOUT(E) +1.0 V
NOTE:
Example:
When VOUT(E) = 1.2V and fOSC = 1.2 MHz, VIN should be 1.7 V, however, VIN should be at least 2.0 V if the minimum operating voltage is 2.0 V
TABLE C
Soft-Start Time vs. Setting Voltage and Oscillation Frequency (IXD3235/36/37 B and G Series only）
SOFT START TIME, µS
SERIES
fOSC
SETTING VOLTAGE, V
MIN
TYP
250
320
250
320
250
320
250
320
MAX
400
500
400
500
400
500
400
500
0.8 ≤ VOUT(E) < 1.75
1.5 ≤ VOUT(E) < 1.8
1.8 ≤ VOUT(E) < 2.5
2.5 ≤ VOUT(E) < 4.0
0.8 ≤ VOUT(E) < 2.5
2.5 ≤ VOUT(E) < 4.0
0.8 ≤ VOUT(E) < 1.8
1.8 ≤ VOUT(E) < 4.0
IXD3235B/G
IXD3237B/G
1.2 MHz
3.0 MHz
IXD3236B/G
IXD3235/36/37 B/G
PS034201-0515
PRELIMINARY
7
ZILOG [ ZILOG, INC. ]
