- 您现在的位置：买卖IC网 > Sheet目录17352 > AS1322 EB (ams)BOARD EVAL AS1322
AS1322
Datasheet - D e t a i l e d D e s c r i p t i o n
8.2 Low-Noise Fixed-Frequency Operation
8.2.1
Oscillator
The AS1322 switching frequency is internally fixed at 1.2MHz allowing the use of very small external components.
8.2.2
Error Amplifier
The integrated error amplifier is an internally compensated trans-conductance (g m ) type (current output). The internal 1.23V reference voltage is
compared to the voltage at pin FB to generate an error signal at the output of the error amplifier. A voltage divider from V OUT to GND programs
the output voltage from 2.5 to 5V via pin FB as:
V OUT = 1.23V(1 + (R 1 /R 2 ))
(EQ 1)
8.2.3
Current Sensing
A signal representing the internal NMOS-switch current is summed with the slope compensator. The summed signal is compared to the error
amplifier output to provide a peak current control command for the PWM. Peak switch current is limited to approximately 850mA independent of
V IN or V OUT .
8.2.4
Zero Current Comparator
The zero current comparator monitors the inductor current to the output and shuts off the PMOS synchronous rectifier once this current drops to
20mA (approx.). This prevents the inductor current from reversing polarity and results in improved converter efficiency at light loads.
8.2.5
Anti-Ringing Control
Anti-ringing control circuitry prevents high-frequency ringing on pin SW as the inductor current approaches zero. This is accomplished by
damping the resonant circuit formed by the inductor and the capacitance on pin SW (C SW ).
8.3 Powersave Operation (AS1322A)
In light load conditions, the integrated powersave feature removes power from all circuitry not required to monitor V OUT . When V OUT has
dropped approximately 1% from nominal, the AS1322A powers up and begins normal PWM operation.
C OUT (see Figure 15 on page 7) recharges, causing the AS1322A to re-enter powersave mode as long as the output load remains below the
powersave threshold. The frequency of this intermittent PWM is proportional to load current; i.e., as the load current drops further below the
powersave threshold, the AS1322A turns on less frequently. When the load current increases above the powersave threshold, the AS1322A will
resume continuous, seamless PWM operation.
Notes:
1. An optional capacitor (C FF ) between pins V OUT and FB in some applications can reduce V OUTp-p ripple and input quiescent current
during powersave mode. Typical values for C FF range from 15 to 220pF.
2. In powersave mode the AS1322A draws only 30μA from the output capacitor(s), greatly improving converter efficiency.
8.4 Shutdown
When pin SHDNN is low the AS1322 is switched off and <1μA current is drawn from battery; when pin SHDNN is high the device is switched on.
If SHDNN is driven from a logic-level output, the logic high-level (on) should be referenced to V OUT to avoid intermittently switching the device
on.
Note: If pin SHDNN is not used, it should be connected directly to pin OUT. V OUT is held at approximately V IN - 0.6V during shutdown.
In shutdown the battery input is connected to the output through the inductor and the internal synchronous rectifier P-FET. Due to the body diode
of the internal synchronous rectifier PFET, V OUT is held at approximately V IN - 0.6V during shutdown. This allows the input battery to provide
backup power for devices such as an idle microcontroller, memory, or real-time-clock, without the usual diode forward drop. In this way a
separate backup battery is not needed.
www.ams.com/DC-DC_Step-Up/AS1322
Revision 1.10
8 - 18
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
A9CAA-0404F
FLEX CABLE - AFG04A/AF04/AFE04T
ISL60002DIH330Z-TK
IC VREF SERIES PREC 3V SOT-23-3
LQW2UASR75J00L
IND 750NH 360MA SRF 360MHZ 1008
AS1326 EB
BOARD EVAL AS1326
EGM06DRMH
CONN EDGECARD 12POS .156 WW
IRDC3710-QFN
BOARD EVAL SYNC BUCK CONTROLLER
LQW2UASR68J00L
IND 680NH 400MA SRF 375MHZ 1008
MAX6160ESA+
IC VREF SERIES ADJ 8-SOIC
相关代理商/技术参数
AS1322_1
制造商:AMSCO 制造商全称:austriamicrosystems AG 功能描述:Low Voltage, Micropower, DC-DC Step-Up Converters
AS1322A
制造商:AMSCO 制造商全称:austriamicrosystems AG 功能描述:Low Voltage, Micropower, DC-DC Step-Up Converters
AS1322ABTTT
制造商:AMS 功能描述:IC STEP-UP DC/DC CONVERTER 6-SOT-23
AS1322A-BTTT
功能描述:IC REG BOOST SYNC ADJ TSOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:50 系列:- 类型:升压（升压） 输出类型:两者兼有 输出数:1 输出电压:5V，2 V ~ 16.5 V 输入电压:2 V ~ 16.5 V PWM 型:- 频率 - 开关:45kHz 电流 - 输出:50mA 同步整流器:无 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 供应商设备封装:8-PDIP
AS1322A-TT_EK_ST
功能描述:AS1322 - DC/DC, Step Up 1, Non-Isolated Outputs Evaluation Board 制造商:ams 系列:- 零件状态:有效 主要用途:DC/DC，步升 输出和类型:1，非隔离 功率 - 输出:- 电压 - 输出:2.5 V ~ 5 V 电流 - 输出:570mA 电压 - 输入:1 V ~ 5 V 稳压器拓扑:升压 频率 - 开关:1.2MHz 板类型:完全填充 所含物品:板 使用的 IC/零件:AS1322 标准包装:1
AS1322B
制造商:AMSCO 制造商全称:austriamicrosystems AG 功能描述:Low Voltage, Micropower, DC-DC Step-Up Converters
AS1322BBTTT
制造商:AMS 功能描述:IC STEP-UP DC/DC CONVERTER 6-SOT-23
AS1322B-BTTT
功能描述:IC REG BOOST SYNC ADJ TSOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2