参数资料
| 型号： | ISL8121IRZ |
| 厂商： | Intersil |
| 文件页数： | 14/26页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QFN |
| 标准包装： | 75 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 2MHz |
| 占空比： | 66% |
| 电源电压： | 4.9 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 24-VFQFN 裸露焊盘 |
| 包装： | 管件 |
ISL8121
magnitude, it is important to understand that the PGD
and OVP thresholds will move in proportion to the
moving reference (externally soft-started reference).
ISL8121 POWER-GOOD OPERATION
The open-collector PGD output reports on the quality of
the regulated output voltage. Once the ISL8121 is
enabled and the VMON pin is above its threshold, PGD
goes open circuit when the output enters the power-good
window (see “Electrical Specifications” table on page 6),
and stays open for as long as the output remains within
the specified window. The PGD is immediately pulled low
if the ISL8121 is disabled by removal of bias, toggling of
the EN pin, or upon encountering of an overcurrent
event; PGD is allowed to report the status of the output
as soon as operation is resumed following any of these
events.
V TARGET
When operating in internal-reference mode, the value of
the reference is known to the ISL8121, so the VMON pin
function can be bypassed by tying it to VCC potential.
VOLTAGE TRACKING AND SEQUENCING
By making creative use of the reference clamps at the SS
and REFTRK pins, and/or the available external reference
input, as well as the functionality of the EN pin, the
ISL8121 can accommodate the full spectrum of tracking
and sequencing options. Figures 13 and 14 offer some
implementation suggestions for a few typical situations.
V TARGET
V OUT
ISL8121
EXT CIRCUIT
V OUT
+
REFTRK
V REF
To V TARGET R S
R P
E/A
+
FB
-
ISL8121
EXT CIRCUIT
+
REFTRK
V REF
VDIFF
R 1
TO V TARGET R S
R P
E/A
+
FB
VSEN+
-
V REF R P
---------------- = ----------------------
+
V OUT R P + R S
-
+
VDIFF
VSEN+
R 1
+
X1 R P
VSEN-
R S
-
TO V OUT
FIGURE 13. COINCIDENTAL VOLTAGE TRACKING
X1
-
V OUT R P
--------------------------- = ----------------------
+
V TARGET R P + R S
VSEN-
-
TO V OUT
FIGURE 12. RATIOMETRIC VOLTAGE TRACKING
The VMON pin is used in external-reference
configurations, where the reference is controlled by a
circuit external to the ISL8121. As such, the ISL8121 has
no way of ‘knowing’ when the external reference has
stabilized to its full value, or is within a certain
percentage of its final value. Thus, the VMON pin’s
functionality can be used to indicate when a desired
threshold has been reached (either by monitoring the
reference itself, or the output voltage controlled by the
ISL8121). By default, when operating in external
reference mode and desiring PGD monitoring as shown in
this datasheet, it is recommended the VMON is set to trip
its threshold when the output voltage (or reference)
reaches 92% of the final set value, choosing the resistor
divider as to achieve a 2% hysteresis.
14
Simple ratiometric external voltage tracking, such as that
required by the termination voltage regulator for double
data rate (DDR) memory can be implemented by feeding
a reference voltage equal to 0.5 of the memory core
voltage (VDDQ) to the reference input of the ISL8121, as
shown in Figure 12. The resistor divider at the REFTRK
pin sets the V OUT level. Select a suitable SS capacitor,
such that the SS clamp does not interfere with the
desired ramp-up time or slope of V OUT .
Coincidental tracking using the internal reference results
in a behavior similar to that presented in Figure 13. The
resistor divider at the input of the differential amplifier
sets the output voltage, V OUT , to the desired regulation
level. The same resistor divider used at the REFTRK pin
divides down the voltage to be tracked, effectively
scaling it to the magnitude of the internal reference. As a
result, the output voltage ramps up at the same rate as
the target voltage, its ramp-up leveling off at the
programmed regulation level established by the R S /R P
resistor divider.
FN6352.2
October 27, 2009
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| ISL8121IRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL8121IRZ-TR5453 | 制造商:Intersil Corporation 功能描述:STD. ISL8121IRZ-T WITH GOLD BOND WIRE ONLY - Tape and Reel |
| ISL8126 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual/n-Phase Buck PWM Controller with Integrated Drivers |
| ISL8126CRZ | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL8126CRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
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